On simulation and GIS, coupling and hydrology
3 views
Formal Metadata
Title 
On simulation and GIS, coupling and hydrology

Title of Series  
Author 

License 
CC Attribution  NonCommercial  ShareAlike 3.0 Germany:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal and noncommercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license. 
DOI  
Publisher 
FOSS4G, Open Source Geospatial Foundation (OSGeo)

Release Date 
2015

Language 
English

Producer 

Production Year 
2015

Production Place 
Seoul, South Korea

Content Metadata
Subject Area  
Abstract 
This presentation shows how to better integrate simulation codes and Geographical Information Systems, and takes the example of Hydrological modelling integration into QGIS. Scientific modelling and simulations are present in a large number of areas. A significant proportion of simulation codes are applied spatially, at different levels, from a neighborhood scale up to worldwide areas. These simulation codes take spatial information as input data, and output results which are related to space too. But most of the time, they do not directly handle GIS data. Data types and data formats are different, and there is therefore a lot of effort to put into preprocessing and postprocessing of the data to get it from GIS to the simulation codes and back. For example, determining the diffusion of a pollutant leak into underground water necessitates to get a DEM, location of the leak, geological data and more from the GIS, and transform it to simulation code input format. Then launch a simulation (on finite volumes e.g.), and convert the output into GIS files so that to be able to visualize spatial repartition of the pollutant according to time. The topic of this presentation is therefore to show how to better interact between simulation and GIS. We present the prevalent types of data for simulation, how they differ from GIS, and how we usually transfer from one type to another. Then we show how we worked towards better integration. Polygonal meshes are the most common way of representing 2D geometries for simulation purposes. Integrating simulation to a GIS requires storing georeferenced meshes in a databases (or using standard GIS file formats), and being able to use simulation values interpolated over the elements as a map layer. We show how to modify simulation codes to read directly a mesh from a GIS and write the results into a GIS. We implemented a new type of layer for QGIS, a mesh layer, which enables to display simulation results with high performances. This takes into account the temporal dimension. We also demonstrate how to integrate a simulation code into QGIS Processing so that it can be managed directly from within the desktop application. We illustrate these concepts with a demonstration of a full integration of a Hydrological simulation tool inside QGIS, with simulation management, custom user interface and strong integration of data between the simulation code and GIS data. In this sense the FREEWAT project started mid2015, which aims at integrating multiple Hydrological codes into QGIS is also a good example of simulation and GIS integration. We end up with the perspectives for more global integration of simulation tools and GIS, and the work still to be done to bridge the gap between those two worlds.

00:00
Area
Mainframe computer
Series (mathematics)
Simulation
Word
Computer simulation
Theory of relativity
Computer animation
Personal digital assistant
Concentric
Helix
Order (biology)
01:24
Domain name
Euler angles
Multiplication sign
Element (mathematics)
Physicalism
Food energy
Mathematical model
Order of magnitude
Particle system
Computer animation
Equation
Differential equation
Resultant
02:33
Point (geometry)
Series (mathematics)
Focus (optics)
Simulation
Matrix (mathematics)
Open source
Multiplication sign
Element (mathematics)
Polygon
Function (mathematics)
Line (geometry)
Table (information)
Computer simulation
Computer animation
Vector space
Forest
Triangle
Vertex (graph theory)
Subtraction
Data type
Metropolitan area network
Resultant
04:37
Point (geometry)
Open source
Real number
Multiplication sign
Client (computing)
Mereology
Attribute grammar
Natural number
Analogy
Internet forum
Lie group
Spacetime
Constraint (mathematics)
Polygon mesh
Demo (music)
File format
Element (mathematics)
Mathematical analysis
Quadrilateral
Generic programming
Bit
Measurement
Connected space
Estimator
Data model
Computer simulation
Computer animation
Software
Order (biology)
Triangle
Vertex (graph theory)
Matching (graph theory)
Sinc function
07:18
Computer animation
07:33
Computer animation
Basis (linear algebra)
Game theory
Data type
Window
Plugin (computing)
08:10
Area
Polygon mesh
Computer simulation
Computer animation
Vector space
Mapping
Multiplication sign
Triangle
Measurement
Arithmetic progression
08:43
Code
Multiplication sign
Source code
Parameter (computer programming)
Function (mathematics)
Web 2.0
Maxima and minima
Mathematics
Core dump
Homography
Software framework
Quantum computer
Social class
God
Physical system
Process (computing)
Electric generator
Spacetime
Wrapper (data mining)
File format
Bit
Measurement
Demoscene
Discounts and allowances
Computer simulation
Hausdorff dimension
Internet service provider
Linearization
Triangle
output
User interface
Escape character
Freeware
Digitizing
Resultant
Point (geometry)
Ocean current
Readonly memory
Game controller
Implementation
Graph (mathematics)
Login
Open set
Twitter
Number
2 (number)
Latent heat
Database
Representation (politics)
Computing platform
Form (programming)
User interface
Polygon mesh
Inheritance (objectoriented programming)
Cellular automaton
Forcing (mathematics)
Projective plane
Element (mathematics)
Physical law
Directory service
Set (mathematics)
Cartesian coordinate system
Table (information)
Word
Uniform resource locator
Computer animation
Visualization (computer graphics)
Vector field
Personal digital assistant
Vertex (graph theory)
Interpreter (computing)
Freezing
17:43
Point (geometry)
State observer
Multiplication
Polygon mesh
Presentation of a group
Code
INTEGRAL
Euler angles
Software developer
Arithmetic mean
Computer simulation
Computer animation
Commutator
Personal digital assistant
Vertex (graph theory)
Interpreter (computing)
Rewriting
Condition number
19:32
Lecture/Conference
00:00
but that's the case and so
00:07
something so if the concentration I was
00:09
saying uh so 1 solution would have some simulation people that we got can often problem historical problem which is usually people from simulation world NGA's word don't talk to each other and so sometimes relation scientists can be pretty hard to understand I don't know if those of the bonds theory uh movie series TV series that they can be kind of weird 84 I know to mean because I was commissioned die before being the DNA as guys so and so helices we get a technology gap to between simulation and yes commission people historically are more into mainframes spot try even a modern and fraud found and so we don't really use it areas so those that can also be difficult to to make both world corroborated of but what I'm going to talk about is trying to bridge the gap between adjacent simulation and the 1st step to bridge the gap is to be to uh talk to on something which is common through 2 balls for order and so actually I 1 as a way to do that is to remember to name 2 of those simulations VCs ation inside yes so what's simulation
01:27
globally commission was 1 you have some dynamic model of of physical attitude is usually modeled by differential equations of physical beauty jurors award and so it's it's usually depending on time which is important and you sort it on a particle domain uh so analytical solution can be used to me because they do not exist so to out through to find the for examples in the NavierStokes equations are pretty complicated non actually we don't know any energy consumers and that so we have that we have to find an approximate solution and we cut down the problem into smaller problems so I we tried to subdivides domain and resolve the problem of computationally on thing elements so what's finitude
02:13
that's an example we take them to global domain and we cut it into a sometimes triangle but so at this small elements and then we solve the question on it so that the magnitude of the problem and so we're going to reserve of we support of semantic entities on the right that's an example of nations and the results
02:33
and basically of the need to element can be introduced 3 D into do you have it's composed of nodes that elements can be a triangle but could be podium on and you get a value for for this element which is a function of X and Y the and there are lots of simulation models answer especially open source emission models are sorry uh lots of enzymes models and for models where we can name a few ones and mn phi useful ways of focus breakthroughs which contribute to to to actually long time ago is for air quality gets swim forest on what's a upon it for drinking but above all because there are lots of them and all of this for example can be g worth man so that your results from simulations can be linked to is linked to territory and you can't you actually during but simulation people not always do this as it just takes data out on to try to visualize atoms square and that's all but we want to do is use lies the reasoning of the series edition of this Eliza was simulation residents into a GIS so and we did the 1st try initially we say OK that's may sounds yet amounts can be a future actually if it's a triangle or polygon we can display that in India is and the value is just not attribute of the future that very simple so I would be the policies or specialized Gossage table but it didn't walk why is that because we got this by at molar problem which is that of the euro you triangles are not connected and you have to repeat the futures Ashraf him for data because you you you want to read out in as lines so it makes huge G. Williams and it's really not efficient are taught to see into ideas so actually does this thing it's elements which are is it's a really a different type of data
04:33
and medicine you find for vector point guard and rest up so I could be for
04:38
example match so at the end of the you know find the and to a very nice
04:44
triangles and Britain's to and
04:47
so it's all about betting that measure into GIS so what we did but what we wanted to do is getting measures which jury France's and getting that representation suitable for the mission and for JS so trying to find something that generic enough to be used for both for the answers that we can the lies in g itself uh suspects are we we need to arbitrary values of knowledge so we need 1 DQG also we didn't uh we want to ask the paretic at constraints we want a nodes to be connected and so the elements to be connected to uh that's not the putting so part of the natural disparity forum uh we want interpolation functions to have to be able to these utilize the values in order to space inside the Phoenix elements uh we want a simple and efficient format 2 we don't want any complicated format and it needs to be seen as a GIS layer layer a when we need that for spatial analysis but we need to see that this mission mesh when we need to compute the nation itself at most is a space it so we comic who came up with a very simple data model with the which is very generic i'd to off nodes which is a point always arbitrary attributes you can have many other attributes you want a lot of the analogies this is OK with S we have a layer of connectivity so it's a 3 or 4 columns depending on forget triangles quads and so that's not ID that's all the nodes are connected to each other and then we have a layer of quizzes for each node so we have the node ID is the time which is you to eat the duration of this nation and the value for us as the submission that's a very simple the as way of a dealing with measures and so uh so another show you a bit of a demo initially wanted to show you some geohydrological g more for nuclear pretend dissemination there which is what we do for a client but it does say no pleased to note a lot and so and as so we get an example with wind that estimation uh where we have a very simple 5 from what that from that's real data from an open source software which is constituted which is wins simulation and the temporal data so I want to show you is that OK these we integrated that into a pretty layer find q swiss account for a guy to so you can see that on a very
07:20
often and 5 tried to find you here on this side of the
07:39
frame the but you can already see that here and so this is yeah but it so we get a
07:58
plugin for like you just return actually to play games we have a plugin which is mostly clear which is a basis to display any may issue you want in in Q so that's a new different type of freer it's not
08:10
last not vector uh it's uh it's may show a tag and so
08:16
here we are open all data and so you see that we have new mesh layer
08:22
and it displays just inside a map for us so unusally here and so we can have 2 measures 1 which is auditory on triangles we use and you that temporal animation was agree where you can see as a progression of the value of the time so this is a win simulations is wind power and over time for a specific area so this
08:45
is a very short general budget so as
08:48
you know uh we did integrates the mesh data into duties and that substitute totally transparent uh we have this implementation which is no already I you have accustomed on the girl's case approach can choose you girls and you have min max and log scarce approach you can change the escape I'd supposed well on the fiery projections so you can get your mates out use mission and put it on top of an openly smart you don't have anything to do with we project of automatically the scene and you get my problem politicians supports as well and the most important thing is it's very performance so that we can run the 70 thousand triangles in under 8 ms whereas Rezo of Denver approach freeze triangle J is fond of you would take on on all 10 or 20 seconds to do that so that's really fast and uh even so fast that that the gene can be a bottleneck getting the data out of the out of the 5 or alter the database and is the bottleneck so that we can the data and mom in memory into provide us with so that's a basic implementation leads not need introduced master of so at what we did was that creating new cutest um mesh layers that's at you just plug in a class which is a new class of scenarios and UGC and see it as a measure your class this class of linear as a mesh that the provider which is in charge of getting the data out of the 5 or can be a database or can be whatever uh from what you want so as this is a the base class and you can write you almost at the provided and by some if you have a simulation from for example here we use a simple ASCII some as simple us defined so that's on the uh and I. D. Nolden value and that's all but we have also developed a special advice provider you could use of a person's space provided that you could use years provided you want to write it but we have also developed some uh custom classes custom tools for current mesh rendering you can see that we do not only wonders nodes as values of this nation adds nodes but also um inside the nodes inside the cell so uh we use open falls out actually and yet is not useful visualizations about for the computation of the the results of the of the of the nation and of the interpretation of corals inside but uh it's not always a pendulum is very easy to do is open OpenGeo and it is to a very great performances the so this is a 1 way we wanted to bridge the gap between simulation and J. being given to these devices mission was on the bigger picture we want to have to just as a simulation platform as well as the idea is not only to movies realize you labels but also to be aboard through the use use Malaysian assimilation and signed as a backend and set up pilots the air the execution from troduce itself so uh not always a processing firm cure go to enter parameters and so specify all you want to run your and you undying will um take into as input your mother parameters you over Europe but inputs from database off off from fires and it will all puts of vector fields the mesh and then you can just this applies it with duties so chooses acts as a greedy as a user interface for use simulation and for preparing the data preparing the parameters and running this mission and send this analyzing so that's a generate simulation platform actually uh which is very interesting between because you can of any kind of solution to do want it we work with the same framework so once you into weighted once mission and I you can to wait another 1 that I want the that complicated and I was assigned for quantum computers and so what is the best aspect of it a set of forms of simulation side you have to separate dismission angry so that's that's very important uh but once you've done it's uh you can do very Creek regeneration for parameters we you is duties because Q discount and uh directly dual eaten interface for the table you have lottery convenience I hugest just processing as simulation robber you that your simulation process which is just something you can execute and then uh risk you just processing you're gonna have a wrapper around its and you can integrate you simulation into the cutest processing workflows you can design with the mouse to different workflows you as on 1 of the element of a workflow is your simulations and then from the From this mission code you can also modified selected in data and parameters from 2 that the base or you can use Q to read from the database whitesupremacist fires and 1 is nation's the that's pretty good although hydrology and so forces days was I do geology I cannot show you that so that's that's a bit about that just the walls on it uh we collected the simulation data and inputs to J is data origin and you it was very specific data formats we did all we said OK you can use suffice and you can use a classic data so that we can idiot we with Q just was very small changes to this mission God but no we get much better user interface and capabilities to do so it it is the use of system using God as outputs so we have 2 important issues which is the nominal could from some of from this mission colored answer now that we have these these rization to we can open directories emissions asked users dismiss mystery and also as output from this side or hydrogeology code we have that 1 D dissemination columns uh which are actually tables of numbers uh which are located at a specific location and we can display 18 with a specific might but he rejects uh which makes chips we make make skewed use see on and you can you have to use for a running and then and the managing your submission got so I don't have any other picture maybe later about us funnel itself is not yet ready and other application would be the free web project the what project is a european age 2020 project and answers the to uh to have tutors says I draw G. platform for prayer postprocessing simulation control and data visualizations so 1 is the uh uh simulation code which will be integrated is mudflows it's a US code for I drudgery and so if want to know more about this project I was about to present it but actually must me and always gonna talk about it up so that 240 another woman trends so you can go see stock and and present a project to be but just a word about the future and on down and so what what we do want to do more of that that's still pretty young but we want to do 3 d at some point because Commission to of the 2 D uh wizards but 2 dimensions but also sweetie may so I would like to others 3 D representation and that could be a an open GL uh window in the future black white it's not done for law but so that's some ideally we would like to actually for the hydrogeology core approach we have a 3 D digitization to it's not an erection of to be used for any kind of treaty measures but still and that's that's a good start to be data I would like to other custom composer we jets API uh because uh as I said uh we have not on the 2 due to the May she's ersity Matias's of that but we can of some other kind of digitization and we'd like to have for example matplotlib graphs inside a composer that we cannot the pdfs very easily uh we source emission data itself and for that we need a custom composer we just CPI to be able to create new compose item in Python so collapsed on the road currently developed will be of practices and of course we want to support you from articles mislabels uh we have currently on only a very specific as the format but so we could support some aged here from model of next year and and on on time to solve
17:46
them some leader and so thank you with this feature of integration thank you for being on time that few how we act as a friend of overtime retirements and opens q J is usually the rewrites and per cent of the called the core and at another point in other this lemma and and that's really huge is developer of regret or of the sun there we get to duties commuters and believe me as the eat steepest code for breakfast so I hand I don't I don't know I know what you're given the effort of your feeding them any questions for questions are would have 1 yes if I understand this correctly and so then the meshes I like you 2 points Hanover show for wired loosely and attitudes are much related to solicit centroids multiple mold themselves so usually when you do simulation you have this mesh and you values can be on the nodes or in the middle of the cell but and but you can go from 1 to another I mean you can interpret as the mean of the so far on its nodes it really depends on your use case and on the kind of condition you view of when an issue but all yourself to the interpretation or not but all model and is based on values on not and then we interpolate 2 observations editions but questions but it thank you thank you were going to have our last since last presenter is low is love here unlikely unless he didn't come will for