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25:41 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

istSOS: latest developments and first steps into the OSGeo incubation process

istSOS (http://istsos.org) is an OGC SOS server implementation entirely written in Python. istSOS allows for managing and dispatching observations from monitoring sensors according to the Sensor Observation Service standard. istSOS is released under the GPL License, and should run on all major platforms (Windows, Linux, Mac OS X). The presentation will go through the details of all the new features that will be packed in the next release. In particular the presenters will introduce enhancements that include the Advanced Procedures Status Page and the istSOS Alerts & Web Notification Service. The istSOS Advanced Procedures Status Page is a new section of the Web graphical user Interface, offering at a glance a graphically representation of the Sensor Network health. Administrators can easily figure out common issues related with sensor data acquisition and transmission errors. The istSOS Alert & Web Notification Service are the result of the Google Summer of Code 2014 outputs. This service is a REST implementation that take inspiration from the OGC Web Notification Service (OGC, 2003; OGC, 2006a) and the Sensor Alert Service (OGC, 2006b) which currently are OpenGIS Best Practices. Alerts are triggered by customized conditions on sensor observations and can be dispatched through emails or social networks. This year istSOS is entering into the OSGeo incubation process, this new challenge will permit to enhance the software quality and consolidate the project management procedures. The presenters will present the incubation status and discuss about the next steps.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
20:49 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Semantic assessment and monitoring of crowdsourced geographic information

Whilst opensource software allows for the transparent collection of crowdsourced geographic information, in order for this material to be of value it is crucial that it be trusted. A semantic assessment of a feature’s attributes against ontologies representative of features likely to reside in this location provides an indication of how likely it is that the information submitted actually represents what is on the ground. This trust rating can then be incorporated into provenance information to provide users of the dataset an indication of each feature’s likely accuracy. Further to this, querying of provenance information can identify the features with the highest/lowest trust rating at a point in time. This presentation uses crowdsourced data detailing the location of fruit trees as a case study to demonstrate these concepts. Submissions of such crowdsourced information – by way of, say, an OpenLayers frontend – allow for the collection of both coordinate and attribute data. The location data indicates the relevant ontologies – able to be developed in Protégé – that describe the fruit trees likely to be encountered. If the fruit name associate with a submitted feature is not found in this area (e.g. a coconut tree in Alaska) then, by way of this model, the feature is determined to be inaccurate and given a low trust rating. Note that the model does not deem the information wrong or erase it, simply unlikely to be correct and deemed to be of questionable trust. The process continues by comparing submitted attribute data with the information describing the type of fruit tree – such as height – that is contained in the relevant ontologies. After this assessment of how well the submitted feature “fits” with its location the assigned trust rating is added to the feature’s provenance information via a semantic provenance model (akin to the W3C’s OPM). Use of such semantic web technologies then allows for querying to identify lower quality (less trustworthy) features and the reasons for their uncertainty (whether it be an issue with collection – such as not enough attribute data being recorded; time since collection – given degradation of data quality over time, i.e. older features are likely less accurate than newer ones; or because of a major event that could physically alter/remove the actual element, like a storm or earthquake). The tendency for crowdsourced datasets to be continually updated and amended means they are effectively dynamic when compared to more traditional datasets that are generally fixed to a set period/point in time. This requires them to be easily updated; however, it is important that efforts are directed at identifying and strengthening the features which represent the weakest links in the dataset. This is achievable through the use of opensource software and methods detailed in this presentation.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
26:00 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Image Geocoding as a Service

Driven by the ambition of a global geocoding solution, in this paper we present the architecture of an image geocoding service. It takes advantage of the ubiquity of cameras, that are present in almost all smartphones. It is an inexpensive sensor yet powerful, that can be used to provide precise location and orientation. This geocoding service provides an API similar to existing ones for place names and addresses, like Google Geocoding API. Instead of a text based query, images can be submitted to estimate the location and orientation of the user. Developers can use this new API, keeping almost all the existing code already used for other geocoding APIs. Behind the scenes, image features are extracted from the submitted photograph, and compared against a huge database of georeferenced models. These models were constructed using structure from motion (SFM) techniques, and heavily reduced to a representative set of all information using Synthetic Views. Our preliminary results shows that the pose estimation of the majority of the images submitted to our geocoding was successfully computed (more than 60%) with the mean positional error around 2 meters. With this service, an inexpensive outdoor/indoor location service can be provided, for example, for urban environments, where GPS fails.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
32:29 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Magical PostGIS in three brief movements

Everyone knows you can query a bounding box or even spatially join tables in PostGIS, but what about more advanced magic? This short symphony of PostGIS examples will look at using advanced features of PostGIS and PostgreSQL to accomplish surprising results: * Using full text search to build a spatially interactive web form. * Using raster functionality to look into the future. * Using standard PostgreSQL features to track and visualize versioning in data. PostGIS is a powerful tool on it's own, but combined with the features of PostgreSQL, it is almost magical.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
25:33 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Intelligent SDIs with MapMint 2.0

This conference aims at presenting the status of the MapMint open source project and its upcoming 2.0 version. The upgrade to newer versions of its core open source components will first be explained. The extensive use of OGC standards through ZOO-Project 1.5, GDAL 1.11 and MapServer 7 is indeed making MapMint an even more stable and efficient foundation to build an open source and standard-compliant spatial data infrastructure. The new metadata related functionalities being developed in interaction with PyCSW and CKAN will also be presented along with the assets of the CSW standard support. The new MapMint responsive user interfaces based on OpenLayers 3 and Bootstrap will also be presented. Both code and documentation improvements will also be detailed. The newly added functionalities in MapMint 2.0 will finally be explained from the developer and user point of views, based on case studies and live examples.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:45 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Building and integrating a Continuous-Integration system within your open source project

So you have an open source project or you want to create a new one. Maybe you have worked on a development project in the past that didn’t have quite the amount of rigor you would have liked. You know you want a build system for your project that is easy to administer, cheap, and powerful, but where do you start? Here is how we implemented our own process using free open source tools. We learned from experience that developers are more focused on solving problems than perceived “housekeeping” tasks. We needed tools that would automate the mundane, repeatable, mechanical, or human-difficult tasks so that developers could focus on what they are good at. We needed a single-sign on through Github to lower any barriers to tool usage that might exist. We needed a dead-simple way to determine if our commits broke functionality anywhere else in code. We needed to track how much of our code was covered by unit tests. Finally, we needed to be able to quickly and easily review each-other’s code and provide feedback. We decided on TravisCI to handle build duties in Maven with a nested project structure and also for its integration with Coveralls. For bug tracking, release scheduling, and task management, we chose WaffleIO for its tight integration with Github issues. One additional feature we desired was static analysis so that simple errors that lie outside of a linter could be caught and reported. This was handled by a combination of Coverity scans and a static analysis tool for Eclipse called Findbugs. Due to our platform support and third-party library (GDAL) requirement, the Github Wiki was the perfect place to keep all setup documents and other helpful articles for end-users and project new-comers. This system for software development worked quite well in most cases. Builds were automated, moderately tested (~40-60% coverage), and complaining to the team loudly via email when things broke. We had a new problem though: build breakages in the master branch and the inability to share code that was not yet fully functional. To alleviate this, we started using the branching and merging functionality that makes Git so valuable. Now, no direct commits occur to the master branch unless in very special circumstances. A developer will see the TravisCI build results before the merge ever occurs, allowing them to adjust code or test cases *before* they cause failures. As a side effect, the merge request workflow allows the team to perform code reviews quickly and easily. Finally, any CI system is not without challenges. Building a continuous integration system has upfront costs that should not be ignored. The payoff from those costs, however, is code/product quality and the avoidance of technical debt. Lastly, some of these CI tools lack support for private repositories.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
26:13 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Advanced Security with GeoServer and GeoFence

The presentation will provide an introduction to GeoServer own authentication and authorization subsystems. We’ll cover the supported authentication protocols, such as from basic/digest authentication and CAS support, check through the various identity providers, such as local config files, database tables and LDAP servers, and how it’s possible to combine the various bits in a single comprehensive authentication tool, as well as providing examples of custom authentication plugins for GeoServer, integrating it in a home grown security architecture. We’ll then move on to authorization, describing the GeoServer pluggable authorization mechanism and comparing it with proxy based solution, and check the built in service and data security system, reviewing its benefits and limitations. Finally we’ll explore the advanced authentication provider, GeoFence, explore the levels on integration with GeoSErver, from the simple and seamless direct integration to the more sophisticated external setup, and see how it can provide GeoServer with complex authorization rules over data and OGC services, taking into account the current user, OGC request and requested layers to enforce spatial filters and alphanumeric filters, attribute selection as well as cropping raster data to areas of interest.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
32:27 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Towards GeoExt 3 – Supporting both OpenLayers 3 and ExtJS 6

GeoExt (http://geoext.github.io/geoext2/) is Open Source and enables building desktop-like GIS applications through the web. It is a JavaScript framework that combines the GIS functionality of OpenLayers with the user interface savvy, rich data-package and architectural concepts of the ExtJS library provided by Sencha. Version 2.1 of GeoExt (currently in alpha-status) is the successor to the GeoExt 1.x-series and brought support for ExtJS 5 and is built atop the following installments of its base libraries: OpenLayers 2.13.1 and ExtJS 5.1.0 (or ExtJS 4.2.1 at your choice). The next version of GeoExt (v3.0.0?) will support OpenLayers 3 and the new and shiny ExtJS 6 (not finally released at the time of this writing). The talk will focus on the following aspects: * Introduction into GeoExt * New features in OpenLayers 3 and ExtJS 6 and how they can be used in GeoExt * The road towards GeoExt 3 * Results of the planned Code Sprint in June (see https://github.com/geoext/geoext3/wiki/GeoExt-3-Codesprint) * Remaining tasks and outlook The new features of OpenLayers (e.g. WebGL-support, rotated views, smaller build sizes, etc.) and Ext JS 6 (Unified code base for mobile and desktop while providing all functionality of ExtJS 5) and the description of the current state of this next major release will be highlighted in the talk. Online version of the presentation: http://marcjansen.github.io/foss4g-2015/Towards-GeoExt-3-Supporting-both-OpenLayers-3-and-ExtJS-6.html#/
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
31:05 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

OSGeo and LocationTech Comparison

We have two great organizations supporting our Free and Open Source Software for Geospatial: The Open Source Geospatial Foundation and LocationTech. Putting on events like FOSS4G is primary responsibility of these software foundations - supporting our great open source software is! This talk will introduce OSGeo and LocationTech, and balance the tricky topic of comparison for those interested in what each organisation offers. We will also look at areas where these organizations are collaboration and explore possibilities for future work. Each of these software foundations support for their existing projects, ranging from "release parties" such as OSGeo Live or the Eclipse Annual Release. We are also interested in the ��incubation�� process each provides to onboard new projects. Review of the incubation provides an insight into an organization's priorities. This talks draws the incubation experience of: * GeoServer (OSGeo), GeoTools (OSGeo), * GeoGig (LocationTech), uDig (LocationTech) If you are an open source developer interested in joining a foundation we will cover some of the resource, marking and infrastructure benefits that may be a factor for consideration. We will also looking into some of the long term benefits a software foundation provides both you and importantly users of your software. If you are a team members faced with the difficult choice of selecting open source technologies this talk can help. We can learn a lot about the risks associated with open source based on how each foundation seeks to protect you. The factors a software foundation considers for its projects provide useful criteria you can use to evaluate any projects.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:33 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

GeoServer for Spatio-temporal Data Handling With Examples For MetOc And Remote Sensing

This presentation will provide detailed information on how to ingest and configure SpatioTemporal in GeoServer to be served using OGC services, with examples from WMS and WCS services. Topics covered are as follows: * Discussion over existing data formats and how to preprocess them for best serving with GeoServer * Configuring SpatioTemporal raster and vector data in GeoServer * Serving SpatioTemporal raster and vector data with OGC Services Tips and techniques to optimize performance and allow maximum exploitation of the available data The attendees will be provided with the basic knowledge needed to preprocess and ingest the most common spatiotemporal data from the MetOc and Remote Sensing field for serving via GeoServer.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:21 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

High-precision open lidar data enable new possibilities for spatial analysis in the canton of Zurich/Switzerland

The department of geoinformation of the canton of Zurich/Switzerland has carried out a high-resolution laser scanning (LIDAR) last year over the entire canton of Zurich. The extensive data (8 pts / m2) have now been evaluated, and a digital surface (DSM) and terrain model (DTM) created (dot grid of 50 cm and horizonal and vertical accuracies of 20 cm, resp. 10 cm. This is the first time high-resolution elevation data is widely available for the entire canton of Zurich. In the past, lidar data have been collected only for small-scale projects. As a novelty, the department has decided to provide the lidar data and its derived products, i.e. DTM and DSM, as open data to the public. With this decision new standards are set not only in terms of accuracy and scope, but also in the usage as open government data. The lidar data can provide valuable support for example in the areas of infrastructure, urban planning, regional planning, natural hazard assessment, forestry, environment, energy, line survey, solar potential analysis, surveying, archeology, agriculture, water or noise. Due to the planned repetition cycle of four years even time series and monitoring projects are possible. Therefore it is not surprising, that since the opening as open data, many interesting applications using this data have been created. The presentation will show the high-resolution data and its possible usage for terrain-visualizations. A selection of the most appealing visualizations will be demonstrated, e.g. an Oculus Rift version enabling the user to navigate through virtual reality. It will further give an insight in the challenge of opening up the LIDAR?data for the public, i.e. setting up an open-data strategy in the cantonal administration of Zurich.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
22:10 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Raster Data In GeoServer And GeoTools: Achievements, Issues And Future Developments

The purpose of this presentation is, on a side, to dissect the developments performed during last year as far as raster data support in GeoTools and GeoServer is concerned, while on the other side to introduce and discuss the future development directions. Advancements and improvements for the management of multidimensional raster data (NetCDF, GRIB, HDF) and mosaic thereof will be introduced, as well as the available ways to manage sliding windows of data via the REST API and importer. Extensive details will be provided on the latest updates for the management of multidimensional raster data used in the Remote Sensing and MetOc fields, including support for WCS EO and WMS EO, and some considerations on the WCS MetOc extensions. The presentation will also introduce and provide updates on jai-ext, imageio-ext, and JAITools. jai-ext provides extended JAI operators that correctly handle NODATA and regione of interests (masks), JAITools provides a number of new raster data analysis operators, including powerful and fast raster algebra support, while ImageIO-Ext bridges the gap across the Java world and native raster data access libraries providing high performance access to GDAL, Kakadu and other libraries. The presentation will wrap up providing an overview of unresolved issues and challenges that still need to be addressed, suggesting tips and workarounds allowing to leverage the full potential of the systems.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:15 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Using the latest ISO standard for geographic information (ISO19115-1:2014)

Release in April 2014, this talk will introduce the major changes of the new standard for metadata on geographic information and what are the benefits for the data managers. It will be illustrated by its implementation in the latest GeoNetwork 3 version and with examples on how the Wallonia Region in Belgium migrated to it.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
16:51 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Revolutionizing map use in Norwegian newspapers

Norway represents one of the countries with most newspapers and media outlets per person. One topic that has an everlasting interest is land registration data - or more commonly: Who bought which properties and what was the price. Land registration data has always been a public data set. Every citizen can request specific information on who has rights to which properties. Up until 1. January 2014 the digital version of this data set was monopolized by law to one vendor - obviously inhibiting innovation. Starting in 2014 - land registration data has been opened and is now accessible to everyone. Webatlas seized this opportunity and hired two summer interns. The task was fairly easy: "Revolutionize the way land registration data is used in local newspapers." After two hard-working months the resulting web application was used by a local newspaper with great results. The newspaper could finally showcase an interactive leaflet map displaying all real estate transactions in the area of interest. Behind the scenes the interns experienced a steep learning curve using PostGIS, GeoServer, Leaflet and a range of excellent plugins. Some of the more stable parts made it to the general use with an Open Source license on GitHub. Today. The solution is used in the majority of Norways newspapers - now showcasing more maps than ever! All made possible by two excellent interns, open data sets and well proven Open Source software components.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
22:46 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Use case of a dual open strategy in the canton of Zurich/Switzerland

With a dual 'open'-strategy the department of geoinformation at the canton of Zurich/Switzerland opts for a strategic orientation towards open source and open data: Open in the sense of an open web-mapping- infrastructure based on open source components: Mapfish Appserver was developed as a framework for building web map applications using OGC standards and the Mapfish REST protocol. It is freely available under the new BSD-license (http://mapfish-appserver.github.io/). The Ruby on Rails gem comes with the following out-of-the box features: - Organize maps by topics, categories, organisational units, keywords and more - Combine maps with background and overlay topics with adjustable opacity - Import UMN Mapserver mapfiles to publish new topics within seconds - Fully customizable legends and feature infos - Creation of complex custom searches - Rich digitizing and editing functionality - Role-based access control on topic, layer and attribute level - Access control for WMS and WFS - Rich library of ExtJS 4 based map components - Multiple customizable viewers from minimal mobile viewer to full featured portal - Multi-site support - Built-in administration backend - Self-organized user groups maps.zh.ch, the official geodata-viewer of the canton of Zurich, was developed using Mapfish Appserver. It contains more than 100 thematic maps and is considered an indispensable working tool for everyone working with spatial data in the canton of Z?rich/Switzerland. 'Open' in the sense of Open Government Data: Zurich is the first canton participating in the national open data portal opendata.admin.ch. The portal has the function of a central, national directory of open data from different backgrounds and themes. This makes it easier to find and use appropriate data for further projects. The department of geoinformatics aims to open as many geo-datasets as possible for the public by publishing them on the national OGD-portal. The open geodata is issued in form of web services ? Web Map Services (WMS), WebFeature Services (WFS) and Web Coverage Services (WCS) - and contains a wide range of geodata from the fields of nature conservation, forestry, engineering, infrastructure planning, statistics to high resolution LIDAR-data.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:57 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Route Planning in your Database with pgRouting

pgRouting extends the PostGIS / PostgreSQL geospatial database to provide shortest path search and other network analysis functionality. This presentation will show the inside and current state of the pgRouting development, from its wide range of shortest path search algorithms to driving distance calculation or Traveling Sales Person (TSP) optimization. Additionally we will give a brief outlook and introduction of upcoming new features like the Vehicle Routing Problem (VRP) solver, and what we have in mind for future releases. We will explain the shortest path search in real road networks and how the data structure is important to get better routing results. Furthermore we will show how you can improve the quality of the search with dynamic costs and make the result look closer to the reality. You will also learn about difficulties and limitations of the library, and when pgRouting might not be not the right tool to solve your routing problem.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
31:40 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Mapping in GeoServer with SLD and CSS

Various software can style maps and generate a proper SLD document for OGC compliant WMS like GeoServer to use. However, in most occasions, the styling allowed by the graphical tools is pretty limited and not good enough to achieve good looking, readable and efficient cartographic output. For those that like to write their own styles CSS also represents a nice alternatives thanks to its compact-ness and expressiveness. Several topics will be covered, providing examples in both SLD and CSS for each, including: mastering multi-scale styling, using GeoServer extensions to build common hatch patterns, line styling beyond the basics, such as cased lines, controlling symbols along a line and the way they repeat, leveraging TTF symbol fonts and SVGs to generate good looking point thematic maps, using the full power of GeoServer label lay-outing tools to build pleasant, informative maps on both point, polygon and line layers, including adding road plates around labels, leverage the labelling subsystem conflict resolution engine to avoid overlaps in stand alone point symbology, blending charts into a map, dynamically transform data during rendering to get more explicative maps without the need to pre-process a large amount of views. The presentation aims to provide the attendees with enough information to master SLD/CSS documents and most of GeoServer extensions to generate appealing, informative, readable maps that can be quickly rendered on screen.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
29:02 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Improving public health delivery in northern Nigeria using open source technologies

  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
24:20 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Case study: A full-fledged cutting-edge FOSS4G map production system

The development and the usage of National Land Survey of Finland's dynamic and high performance map production system is described in this presentation. The system is currently in use and serves map images both to customers and to NLSFI production systems. The data in the map production system are open data and being updated on a weekly basis. When the data get updated, a RSS-feed is generated. Based on the feed, the map products are updated. Data is stored, updated and replicated in PostGIS. Map pictures are rendered in GeoServer. The visualization of the maps is based on SLD-stylesheets. SLD-stylesheets enable the same data to be visualized in several different ways. GeoServer in conjunction with SLD-stylesheets offers a Web Map Service (WMS). Map images are delivered via a high performance MapCache Web Map Tile Service (WMTS) and as image files via NLSFI download service. The system is designed to be expandable and is currently being further developed to enable the pro-duction of on-demand printed maps.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
23:23 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Open Source and Open Standard based decision support system: the example of lake Verbano floods management.

The Locarno area (Switzerland, Canton Ticino) is exposed to lake floods with a return period of about 7-8 years. The risk is of particular concern because the area is located in a floodplain that registered in the last decades a great increase in settlement and values of the real estates. Moreover small differences in lake altitude may produce a significant increase in flooded area due to the very low average slope of the terrain. While fatalities are not generally registered, several important economic costs are associated, e.g.: damages to real estates, interruption of activities, evacuation and relocation and environmental damages. While important events were registered in 1978, 1993, 2000, 2002 and 2014 the local stakeholder invested time and money in the set-up of an up-to-date decision support system that allows for the reduction of risks. Thanks to impressive technological advances the visionary concept of the Digital Earth (Gore 1992, 1998) is being realizing: geospatial coverages and monitoring systems data are increasingly available on the Web, and more importantly, in a standard format. As a result, today is possible to develop innovative decision support systems which mesh-up several information sources and offers special features for risk scenarios evaluation. In agreement with the exposed view, the authors have recently developed a new Web system whose design is based on the Service Oriented Architecture pattern. Open source software (e.g.: Geoserver, PostGIS, OpenLayers) has been used throughout the whole system and geospatial Open Standards (e.g.: SOS, WMS, WFS) are the pillars it rely on. SITGAP 2.0, implemented in collaboration with the Civil protection of Locarno e Vallemaggia, combines a number of data sources such as the Federal Register of Buildings and Dwellings, the Cantonal Register of residents, the Cadastral Surveying, the Cantonal Hydro-meteorological monitoring observations, the Meteoswiss weather forecasts, and others. As a result of this orchestration of data, SITGAP 2.0 serves features that allows, for example, to be informed on active alarms, to visualize lake level forecasts and associated flooding areas, to evaluate and map exposed elements and people, to plan and manage evacuation by searching for people living in particular areas or buildings, by registering evacuation actions and by searching for evacuated people. System architecture and functionalities, and consideration on the integration and accessibility of the beneath information together with the lesson learnt during the usage of the system during the last floods of November 2014, provides interesting discussion points for the identification of current and future needs.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
25:21 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

OGC GeoPackage in practice: Implementing a new OGC specification with open-source tools

GeoPackage is a new encoding standard created by the Open Geospatial Consortium as a modern alternative to formats like SDTS and Shapefile. Using SQLite, the single-file relational database can hold raster imagery, vector features and metadata. GeoPackage is an ideal data container for mobile devices such as smartphones, IoT devices, wearables, and even automobiles. We have created a few open-source tools to manipulate this exciting technology in a way that is useful to the geospatial community. Our goal with the GeoPackage specification implementations is simple: Create GeoPackages quickly and reliably while maintaining standard conformance. The single biggest issue we have faced is the speed in which large amounts of imagery can be disseminated to the end user. Data standards reliability was also a concern because we found many vendors interpreted the specification differently or to suite their own needs. Finally, the main problem GeoPackage was created was to solve was interoperability. We set out to create an implementation that would guide other parties towards making a data product that would function as well on one platform as it would on a completely different platform. Our initial implementation of the GeoPackage specification was created using Python 2.7.x. The software design was intended for command line use only in a script-friendly environment where tiling speed was paramount. The Gdal2tiles.py script was improved upon by harnessing the Python multiprocessing library so that multiple tile jobs could run simultaneously. The other piece of the workflow, creating GeoPackages, would be a separate development effort from scratch called tiles2gpkg parallel.py. In tiles2gpkg parallel.py, we implemented multiprocessing by writing to separate SQLite databases in parallel and then merging the tiled data sets into one compact database. This implementation worked well and increased the performance of producing these data sets; however, the command line design means that all but the most technically adept users would struggle to use the tools. With the initial Python implementation getting early-adopters a preview of GeoPackage in the short term, our team set out to make a production-quality GeoPackage API that could satisfy all user needs. Named Software to Aggregate Geospatial Data or SWAGD, we created a robust library for tiling raster data, packaging raster data stores into GeoPackages, and viewing either the raw tiles OR the finished GeoPackage products within a map viewer. Additionally, a Geopackage verification tool was created to foster community adoption. For more information, see our Github site here: https://github.com/GitHubRGI/swagd. Many open-source tools are being leveraged on the SWAGD project, including many common build and continuous integration tools including Github, TravisCI, WaffleIO, and Coverity. Using proven software development mechanisms like unit testing and code reviews we now have a consistent, reproducible, and inclusive GeoPackage implementation. We have an aggressive list of future capability that we would like to develop including ad-hoc routing on a mobile device, vector tile data sets, and even 3D support.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
22:59 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

ZOO-Project 1.5.0: News about the Open WPS Platform

ZOO-Project is an Open Source Implementation of the OGC Web Processing Service (WPS) available under a MIT/X-11 style license and currently in incubation at OSGeo. ZOO-Project provides a WPS compliant developer-friendly framework to easily create and chain WPS Web services.This talk give a brief overview of the platform and summarize new capabilities and enhancement available in the 1.5.0 release. A brief introduction to WPS and a summary of the Open Source project history with its direct link with FOSS4G will be presented. An overview of the ZOO-Project will then serve to introduce new functionalities and concepts available in the 1.5.0 release and highlight their interests for applications developers and users. Evolutions and enhancements of the ZOO-Project WPS server (ZOO-Kernel) will first be detailed especially regarding compliancy (WPS 1.0.0 and 2.0), performance and scalability. The ZOO-Project optional support for Orfeo Toolbox and SAGA GIS will then be introduced, with details on the numerous new WPS Services (ZOO-Services) they provide. Use and connexion with other reliable open source libraries such as GDAL, GEOS, MapServer, GRASS GIS, CGAL will also be reviewed. Examples of concrete applications will finally be shown in order to illustrate how ZOO-Project components (ZOO-Kernel, ZOO-Services, ZOO-API and ZOO-Client) can be used together as a platform to build standard compliant advanced geospatial applications. Along with the new 1.5 release, this talk will also present how ZOO-Project is being developed, extended and maintained in the context of the EU funded PublicaMundi research project.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
24:29 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Leaflet vs. OpenLayers: which is best for our indoor maps?

Leaflet and OpenLayers are two well-known javascript libraries for embedding interactive maps in a web page, and each of them comes with pros and cons which are not obvious. Having worked with both libraries for indoor applications, we will in this presentation offer insight on which of them is more suited to a variety of situations and requirements, and which challenges they should overcome in the future.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
22:27 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Earning Your Support Instead of Buying it: A How-to Guide to Open Source Assistance

More organisations are moving to use FOSS4G software to cover shrinking budgets. It is very appealing to an organization’s leaders to ditch their current proprietary software solution with the attendant saving on per user licences and ongoing maintenance costs. Obviously, if you switched to FOSS4G to get better features and scalability you should consider buying a support contract from one of the many vendors that offer them, these companies support many of the core developers directly. This way you get all the advantages of open source, prompt support and often the chance to ask for new features. However, if you (or your boss) are looking to save money then you are moving from a cash economy to a gift economy. In a gift culture you need to build up your “capital” before attempting to take too much out. For example, you’ve downloaded the software and installed it, and all looks good. Then disaster hits, you have a demo for the CIO and nothing's working; Time to hit the user list, the developer list, stack exchange. Why can’t you get an answer? Remember just because your issue is urgent to you the developers might be in the middle of a new release or adding a new feature and have more important (or fun) things to do with their time. They will notice they have never seen your name before on the list, or on Stack Exchange that you have a reputation in the single digits – thus you are a newbie. There’s no harm in that but wouldn’t it be better to have got that out of the way before your emergency. You could have built up your reputation by asking some questions earlier especially questions like “what can I do to help?” or “I found an unclear paragraph in the install instructions, how do I fix it for you?” on a mailing list. On StackExchange you can build reputation by asking good questions and by answering other people’s questions. Once you’ve banked some capital there are still good and bad ways of asking a question. Developers are busy people (the GeoTools users list has 20-30 messages a day for example) no one has time to read all of them closely. If you use a poor subject (e.g. "Help!!!!") or don’t provide a clear description of the problem (e.g. “it crashes”) then the odds of being ignored are huge. It can be tempting once you have found a helpful developer to keep emailing them directly, but this is likely to lead a polite(ish) reminder to keep to the list so that everyone can benefit or silence. This talk will show how to be a better open source citizen and get a better answer than RTFM when your project is stuck and the demo is the next day. The author will share his experience with helping users and developers on the GeoTools and GeoServer mailing lists and as a moderator on gis.stackexchange.com.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
21:12 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

MapCache: Fast and Featureful tile serving from the MapServer project

MapCache is a tiling server component designed to be efficient while still comprising all the features expected from a modern tiling solution. This presentation will give a brief presentation of the MapCache tiling solution, along with the recent developments that were added to reply to the needs of large scale installations (cache replication, load balancing, failsafe/fallback operations, large cache management, etc...)
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
19:50 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

WPS Benchmarking Session

The yearly Web Processing Service (WPS) benchmark. Variuos WPS implementations will be tested regarding their capabilities, compliancy to the standard and performance. Traditionally, each participating project designates individuals from their community to participate in this talk to introduce their project and summarize its key features. The focus this year will be on compliancy and interoperability. We will present the test set-up, participating WPS projects and the results of the benchmark.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
24:22 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Jsonix: Talking to OGC Web Services in JSON

Can you talk to OGC Web Services in JSON instead of XML? You can - with Jsonix, a powerful JavaScript tool for XML - JSON conversion. JSON has probably already replaced XML as a "lingua franca". JSON is much lighter and easier to use than XML, especially in JavaScript-based web apps. In the context of GIS, web mapping is dominated by JavaScript libraries like OpenLayers and Leaflet, which speak JSON natively. But what about the standards? Open Geospatial Consortium defines more than 50 specifications with more than 100 individual versions. Technically almost all of them are XML-based and defined by XML schemas. These are de jure and de facto standards, widely used and well supported. So you still need XML processing in JS web mapping apps. Processing XML is no rocket science, but it's seldom a pleasure to implement. The OL3 KML parser is about 2.5KLoc of dense XML parsing. Even a very simple WMS GetCapabilities format is almost 1 KLOC. From this code around 90% is pure XML parsing and only 10% is the processing of the payload. Would not it be nice if we could talk to the OGC Web Services directly in JSON? So that the developers could focus on the 10%, the payload processing, and cut off the 90% (XML handling) of the effort. Jsonix is an open source library for XML - JS conversion which makes it just possible. With Jsonix you can take an XML Schema and generate XML - JS mappings. These mappings allow you to parse XML in the original schema and get your data in pretty JSON. It also works in the opposite direction: you can serialize JSON in XML, which would correspond to the original XML Schema. What makes Jsonix unique is that it is type and structure-safe. On the JSON side, you will get types and structures exactly as they are defined in the original XML Schema. For instance, xs:decimal is converted into a number in number in JSON, repeatable elements are represented by arrays etc. You just need the corresponding mapping. You can generate Jsonix mappings on your own or use one of the pre-generated mappings. The (unofficial) OGC Schemas Project compiles and provides mappings for many of the popular OGC schemas (OWS, WMS, WFS, CSW, SLD and many more). This presentation gives an overview of Jsonix demonstrates its usage by a number of examples.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
23:48 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

New QGIS functions for power users

QGIS has seen a large amount of new functions and improvements during the last few years. And there is still more to come. This presentation shows the most recent changes and new functionalities in the codebase after version 2.8, both from a users and from a technical point of view: Curved geometries have long been a missed feature in FOSSGIS Desktop solutions, with such geometries usually ending up being segmented on import. A rewrite of the QGIS Geometry core now allows for native support of a number of curved geometry types, such as CircularString, CompoundCurve, CurvePolygon, etc., in addition to the traditionally supported Point, Line and Polygon geometries. As part of the redesign, proper support for M and Z coordinate values was also implemented for all supported types. Geometry errors can easily sneak into large datasets, either because of inexact data acquistion, but also due to gradual loss of precision when importing, exporting and converting the datasets to different formats. Manually detecting and fixing such issues can be very time consuming. To assist users confronted with such problems, the 'Geometry checker' has been developed. It provides the functionality to test a dataset for geometry and topology issues (such as duplicate nodes, overlaps, gaps, etc), presenting a list of detected faults. For each error type, the plugin offers one more more methods to automatically fix the issue. A third new function in the geometry domain is the snapper plugin. It allows to automatically align the boundaries of a layer to a background layer (e.g. align the parcel boundaries with a road background layer).
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
23:26 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Big data analysis with Tile Reduce and Turf.js

Tile Reduce is a new open source map reduce frame work for analyzing massive geo data. Tile reduce is a tile analysis framework built on the javascript GIS library Turf.js. It runs on your local computer or in the AWS cloud and scales to run thousands of processors in parallel. At Mapbox we use Tile Reduce to detect issues in global street vector data like OpenStreetMap, data comparison and data conflation. This talk will walk through the architecture of Tile Reduce, highlight advantages, limitations and future developments.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
24:31 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Dynamic dashboards with D3.js and CartoDB

NextGIS has been busy working on a new stack of geospatial software for the past few years and we're finally ready to present what we've accomplished. Our stack consists of 4 major components: web (NextGIS Web), mobile (NextGIS Mobile), desktop (NextGIS QGIS) and data management (NextGIS Manager). Three of those components are brand new, developed by NextGIS alone and were released just recently. For the fourth component, we participate in QGIS development since 2008 and use its codebase for our desktop component. The main focus of the stack is tight integration, ease of use and modularity. New stack features unique features, to name just the few: plugable renderers for NextGIS Web, multi-layer support for NextGIS Mobile, super-fast rendering and great formats support for NextGIS Manager and all-around integration with NextGIS QGIS. The presentation will provide an overview and will look at general architecture, use cases and plans for future development.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
1:03:54 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

FOSS4G Seoul 2015 - panel discussion

  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
25:41 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Don't Copy Data! Instead, Share it at Web-Scale

Since its start in 2006, Amazon Web Services has grown to over 40 different services. Amazon Simple Storage Service (S3), our object store, and one of our first services, is now home to trillions of objects and core to many enterprise applications. S3 is used to store many kinds of data, including geo, genomic, and video data and facilitates parallel access to big data. Netflix considers S3 the source of truth for all its data warehousing.The goal of this presentation is to illustrate best practice for open or shared geo-data in the cloud. To do so, it showcases a simple map tiling architecture, running on top of data stored in S3 and uses CloudFront (CDN), Elastic Beanstalk (Application Management), and EC2 (Compute) in combination with FOSS4G tools. The demo uses the USDA��s NAIP dataset (48TB), plus other higher resolution city data, to show how you can build global mapping services without pre-rendering tiles. Because the GeoTIFFs are stored in a requester-pays S3 bucket, anyone with an AWS account has immediate access to the source GeoTIFFs at the infrastructure level, allowing for parallel access by other systems and if necessary, bulk export. However, I will show that the cloud, because it supports both highly available and flexible compute, makes it unnecessary to move data, pointing to a new paradigm, made possible by cloud computing, where one set of GeoTIFFs can act as an authoritative source for any number of users.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
19:41 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

DigitalGlobe and Open Source

Adding some important and pertinent information to this abstract with respect to the recent tragic events in Nepal. DigitalGlobe, in responding to the devastating earthquake in Nepal, has openly licensed both pre-event and post-event imagery, as well as openly licensed the results of our Tomnod campaign, which has crowdsourced information from nearly 50,000 volunteer contributors to assess damage and displaced people in Nepal. DigitalGlobe is working with first responders, aid relief and NGOs including Kathmandu Living Labs, Humanitarian OpenStreetMap Team, the UN, IFRC and American Red Cross. We are providing important information to disperse relief to the growing number of displaced people. The work we have done has been featured by CNN, CCTV, Mashable, the Atlantic and many more. Please reference links below. This is a poignant example of how Geospatial data, provided in the open can benefit millions of people who need help. http://www.cnn.com/videos/business/2015/05/01/wbt-intv-lake-bullock-nepal-digitalglobe.cnn http://www.theatlantic.com/technology/archive/2015/05/the-mapmakers-helping-nepal/392228/ http://www.citylab.com/tech/2015/04/how-amateur-mappers-are-helping-recovery-efforts-in-nepal/391703/ http://mashable.com/2015/05/06/landslide-nepal-photos-before-after/#:eyJzIjoidCIsImkiOiJfdTVjdzgyb2M5aGRnMnZ1bCJ9 Original abstract: DigitalGlobe operates a constellation of high resolution, high accuracy satellites. Imagery from DigitalGlobe can be seen in Mapbox Satellite, CartoDB, Google Maps, HERE Maps, Bing Maps, Apple Maps and is often used for the purposes of contributing, editing and validating for OpenStreetMap. Over the years, DigitalGlobe has provided both imagery and software processing tools with an Open Source license. This includes post-event imagery for Typhoon Haiyan in the Philippines and the Japanese Tsunami. Recently, we open sourced a software toolkit called "Mr Geo" http://defensesystems.com/articles/2015/01/14/nga-open-sources-geospatial-analysis-tool.aspx This presentation will give an overview of DigitalGlobe, our geospatial technology and our services we are providing to the Open Source community.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
23:46 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Modifications to Web Processing Service Standard For Client-Side Geoprocessing

Nowadays we see the rapid growth of solutions number for spatial data processing in the Web (i.e. geoprocessing). One of the main trends of Web geotechnologies evolution is the transition from Web map applications to the Web GIS applications, which are supplement the maps delivery with the analytic tools providing to the end user through Web interface. The only general open standard describes implementation rules for Web geoprocessing services. This is the Open Geospatial Consortium Web Processing Service standard (OGC WPS), which is server-oriented standard [Schut at al., 2007]. Moreover, the vast majority of currently used solutions (both open source and proprietary) are server-oriented, i.e. assume the using for computations the server resources only. However, some researchers underline that it is possible way to transmit the executable code to the client for client-side computations and geoprocessing [Keens at al., 2007]. Also, some general Web architecture concepts assumes the effectiveness of client-side computations, e.g. Fog Computing concept [Hong at al., 2013]. Our practical experience also shows that in some cases it is useful to have ability of client-side geoprocessing, which is not opposite but complement technology to the server-side processing technologies. In addition, we believe that it is more useful to have the ability to run the same processing tool by choice on server or client side. We name such double-sided services as Hybrid Geoprocessing Web Services (HGWS) [Panidi, 2014]. We study and discuss the approaches to fill the gap of client-side geoprocessing general schema. For this purpose, we implemented previously the getProcess request as addition to the WPS protocol [Panidi, 2014]. Additionally at the previous steps of our study, we proposed a possible structure of getProcess request and draft XML schema for its response, which describes the list of executable resources and their dependencies [Kazakov at al., 2015]. Currently we working on detailed methodology of processing tools implementation, and prototypes testing in use cases of geospatial data processing for small-scale research projects. We use the Python programming language as primary development tool, because of its applicability to build both server- and client-side processing tools using single core program code. We use Python also for implementation of needed infrastructure components, such as HGWS server that supports the getProcess request/response performing, and client-side runtime environment that provides executable code orchestration on the client. Achieved results need to be discussed widely and carefully. However, main conclusion of our current work is that client-side geoprocessing schema in general could be relatively simple and compatible backward with current standards. The HGWS concept is applicable when implementing client-side geoprocessing Web services in small-scale projects and could be the entering point for study of distributed geoprocessing systems implementation.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
26:21 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

An On-board Visual-based Attitude Estimation System For Unmanned Aerial Vehicle Mapping

A visual-based attitude estimation system aims to utilize an on-board camera to estimate the pose of the platform by using salient image features rather than additional hardware such as gyroscope. One of the notable achievements in this approach is on-camera self-calibration [1-4] which has been widely used in the modern digital cameras. Attitude/pose information is one of the crucial requirements for the transformation of 2-dimensional (2D) image coordinates to 3-dimensional (3D) real-world coordinates [3]. In photogrammetry and machine vision, the use of camera’s pose is essential for modeling tasks such as photo modeling [5-8] and 3D mapping [9]. Commercial software packages are now available for such tasks, however, they are only good for off-board image processing which does not have any computing or processing constraints. Unmanned Aerial Vehicles (UAVs) and any other airborne platforms impose several constraints to attitude estimation. Currently, Inertial Measurement Units (IMUs) are widely used in unmanned aircrafts. Although IMUs are very effective, this conventional attitude estimation approach adds up the aircraft’s payload significantly [10]. Hence, a visual-based attitude estimation system is more appropriate for UAV mapping. Different types of approaches to visual-based attitude estimation have been proposed in [10-14]. This study aims to integrate optical flow and a keypoints detector of overlapped images for on-board attitude estimation and camera-self calibration. This is to minimize the computation burden that can be caused by the optical flow, and to fit in on-board visual-based attitude estimation and camera calibration. A series of performance tests have been conducted on selected keypoints detectors, and the results are evaluated to identify the best detector for the proposed visual-based attitude estimation system. The proposed on-board visual-based attitude estimation system is designed to use visual information from overlapped images to measure the platform’s egomotion, and estimate the attitude from the visual motion. Optical flow computation could be expensive depending on the approach [15]. Our goal is to reduce the computation burden at the start of the processing by minimizing the aerial images to the regions of upmost important. This requires an integration of optical flow with salient feature detection and matching. Our proposed system strictly follows the UAV’s on-board processing requirements [16]. Thus, the suitability of salient feature detectors for the system needs to be investigated. Performances of various keypoints detectors have been evaluated in terms of detection, time to complete and matching capabilities. A set of 249 aerial images acquired from a fixed wing UAV have been tested. The test results show that the best keypoints detector to be integrated in our proposed system is the Speeded Up Robust Feature (SURF) detector, given that Sum of Absolute Differences (SAD) matching metric is used to identify the matching points. It was found that the time taken for SURF to complete the detection and matching process is, although not the fastest, relatively small. SURF is also able to provide sufficient numbers of salient feature points in each detection without sacrificing the computation time.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
22:10 FOSS4G, Open Source Geospatial Foundation (OSGeo) English 2015

Landmark Based Path Planning with a Linear Map Display For Mobile Map Applications

Landmarks are yet to be integrated with mainstream mobile phone based navigation aids. In geographical regions where land marks are commonly used by the community for navigation support, the lack of them in electronic navigation aids make them less useful for such communities. In this study a land marks based navigation model is derived considering the value of them for local community in Sri Lanka. The landmarks can be prominent or not, make sense only during certain time of the day or been important differently for people with different age groups. We assume that the attributes of landmarks can be used to give a strength value for them for navigation. In this study three parameters, the visibility of them at different time of the day, the horizontal spread of the landmark and the height of them are considered as attributes which gives strength to a landmark. First, to give more importance to landmarks, we have developed an algorithm where not only the distance of a route but the strength of landmarks is also considered when selecting the best route to navigate. The A* Algorithm is used as the base which output possible shortest paths considering only the distance. This algorithm was enhanced to output the optimum paths considering both the distance and the strength of landmarks along it. If the route is having more strength related to landmarks, it is prioritized. The route��s strength is defined based on number of landmarks visible along it and the strength of them. In order to calculate the number of landmarks along a route a landmark buffer is used. The day/night visibility and the height/spread are used to calculate the strength of the landmarks along the route. We have identified that after placing landmarks on a mobile screen which have limited size, the map become too congested and it becomes difficult to read the navigation path. This is more prominent when the path is having many turns. Therefore, secondly, to utilize the limited mobile screen in more effective manner, we reduce the selected path to a linear map which shows the path reducing curves but emphasising the turns by markers. The linear map shows landmarks around significant turns and provides guidance based on landmarks. The turn confirmations are calculated based on landmarks. Douglas-Peucker algorithm is used to derive the linear path and is enhanced to identify turns and show the landmarks around those turns. A prototype implementation is done using mobile web approach to reduce the platform dependency. In the simple mobile web application developed, jQuery mobile, and php are used for the user interface development and server side implementations respectively. PostgreSQL with postGIS capabilities and pgRouting is used as a spatial database. Web services and smart queries are used to implement the basic functionality communicating with the spatial database and the front end. The application is still being implemented and tested in Sri Lanka at the moment and the outcome would be reported in due course.
  • Published: 2015
  • Publisher: FOSS4G, Open Source Geospatial Foundation (OSGeo)
  • Language: English
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AV-Portal 3.7.0 (943df4b4639bec127ddc6b93adb0c7d8d995f77c)