Nobody cares about your datum: or the Kleinstaaterei of spatial reference systems

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Formal Metadata

Title
Nobody cares about your datum: or the Kleinstaaterei of spatial reference systems
Title of Series
Part Number
24
Number of Parts
193
Author
Metcalf, Calvin (AppGeo)
License
CC Attribution 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 purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
DOI
Publisher
FOSS4G, Open Source Geospatial Foundation (OSGeo)
Release Date
2016
Language
English
Production Place
Bonn

Content Metadata

Subject Area
Abstract
What is the difference between people that make maps and GIS people: GIS people waste much of their time dealing with spatial reference systems while people making maps just avoid them like the plague and instead focus on the projections they need to use to represent their data with. Most discussions on the topics of projections and spatial reference systems is mainly on the large number of small spatial reference systems each used by a limited number of groups. Work for the state of Massachusetts, use EPSG 2805, work for the Boston police? then you use EPSG 2249. This talk will focus on the gap between how projections work in theory vs how people constantly waste their time dealing with projections. Most of the mental energy spent on projections and spatial reference systems is spent on incompatible local systems used for storage of data, which are also known as internal details nobody should care about with disproportionate time spent converting between datums whose differences are smaller then the precision of the data.
Keywords
AppGeo
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it it we can also the crystal so after the
Calvin that the that's going to talk about nobody cares about your data all
of the lines stuff that I all spatial reference so I'm very eager to hear you have to have a high of so by the square root donors my talk was going to be like I am going to do all these analogies between spatial reference systems in the state of the the state of at the end the state of
the Holy Roman Empire that today on
it turns out you cannot get a sheet piles of the Holy Roman Empire for less than like 800 euros
I I spent far too much time trying to find a historical medieval German Jewish files and a parent you know a lot of other countries you can get this data but apparently when there is an actual country somewhere they tend to not have a kind of data on we have about our
vertical that Jim on they're not really figure in this talk but they the Committee come out here so many of them a shadow on we have a later talk to Martin Jonas did you want to learn about writing w must services in the cloud all the the and today
we're going to talk about project for or jets finally you hang here people from the states but I will reveals Adele's completely my
company if you have a
person if you're a small local government partial that the you like when a man we
can have you go talk to Michael Turner whether you will be happy to so community has some fantastic software called map does also basin of tools but Proj for
j at so this is a library that I maintain I the we so on
it that individual work and I wrote this document
into the runners dog didn't for us to produce a fascinating
but it is a it's a big
library so we're just going to show in the back of some of the slides is a Cuban talking different projections we talk we we they're
supported in broad for just a signal from the over the scope of library all the other
projections have a short the Nazis other products strings that are that I post JS users and we have the aliases
there that Wellman text uses so you can have so
for instance hours will
areas also called always conic area note the creative use of underscores they're all systems that use other ways different
words and then you have just calling Albert because don't have as much
as so my involvement of private yes I started with
something about on Twitter I'm doing a lot of my open source stuff starts on either shape faster
because I'm masochist and I wanted I wanted to be able to just drag drop the shape file on the map is a jet on mapping this work but you should file so that the people that have their own production so you get is driving the obviously in Massachusetts State meters and have it work because goes after projecting will that and and property right wasn't really work turned out was not
actually being maintained by anybody these days so I don't want I started there was no really so in way to figure out the
API was in an ad hoc pipeline built system and it had little synchronous but every
time you used to new EPS decode it would actually go over and aquarium spatial reference and try to download the people in text files and if anybody is you spatial reference up or you will know that there's also a unmaintained thing that it's on frankly shocked and it still works because I don't believe anybody actually actively maintained in these days of like this the so is in several of the apocalypse that building so you may remember that 1 about a decade ago it was a early web mapping library that this built like
w cells I was in to pull out that something is it was very much Java or C + + this not translated JavaScript transliterated because the use of all of those jobs principles plus object-oriented idioms and it is did not look very much like John script and the a lot of
this sort of exhaustive it doesn't really it's it's it's having more in common with with evolution and you know intelligent design often like nobody can use to like this is like a crater like our segmentation by Blair interval whereas the 2 different people coming in so after a while I ate it was sort of like it made every time I did some code actinides maybe you want to license Haskell afterwards because because it was a sort of like everything that was wrong about object-oriented programming is sort of like everything's globally mutating the state and nothing returns anything in sort of just and can see that there is a public there is like a series of of rational choice that would lead up to their billing you just areas like I don't know what's happening anywhere like he
added there is no simple is there's a lot of these incidents like 70 and is trying to figure out like this what happens where and it is this transparent needed by I the I was looking through and all as references to great shifts but no way to actually give a breach of file so this is no rigid format works in browser so sort of like that we can get rid of life have the data and transform life because no way to get to about much to here's sentences so 1 this closest to get rich working abroad for just the of the iceberg very odd of all control flow of meeting in inside there will when I started and there's actually still a couple of bugs we've had recently where if you project if you if you do a projection several times in a row you'll get different results because of this stuff in getting we did it on the on the actual like projection yeah that was fun to find out of the I doing it again it doesn't give us anything
so it is also a the flags in terms this 1 has a term called check that it said causes the so flip by you can find it anywhere like there's no so I don't think at least the busy everything from the the woman everything to the definition of copied onto an object so it might be a need to find somewhere so I don't know that's important produced during like there any way to actually look that observe this like a legacy from the previous like Java C + + version that does supported so and jacket and
then in Bradford as said the jet finding from for yeah but for the analyze it things I don't know if it's is a legacy from that orbits the star of the units this version but in a course like all good algorithmic stuff all of the single all of the actual production code is full of seeing whether variables there are usually similar but sometimes it's slowly idioms like some them have like x and y someone you know X and some will be Latin long solely you know and and land it's just a little aliases variants the D 3 production actually uses unit of land the characters on that is but sometimes but again it's not space and everything is on this 1 object it's very hard to tell like what's actually important and was copied over so many times when breaks and there's like needles but some of the stuff on here and see if that works maybe I actually to call this parameter something else and mental work of latitude of origin is of latitude 0 it's a good yes I is also
dangerous which are very intimately intertwined with the projection stuff that's why there is a lot along direction which simply returns we you gave it because there's no it actually due date and shipped without doing a projection so that some function of their
a so that students the issue is I alluded to earlier you know the way projections are communicated around it is quite a bit of a problem yeah this is a good match so it is my opinion the 1 result representation of corn reference systems is empirically objectively the worst form like I just loaded his own bespoke susurration format but it's not expressions it's not XML it's not anything that anybody else uses it is its own way quality it's like the rest of all attacks it's that you have like property square brackets 1 or more things which include other properties with square brackets is sort like why I the my my possible writing is just simply flipped the 1st during and the 1st term in the bracket around so becomes an expression like list and that's why super easy to parse because that's just the end of the visible light on so it hasn't been
don't like a lot of light status of have will use in the update step to you know to take that into account this is not the case with that the following that the good every single old projection I've ever seen uses the word keyword projection to define what the projections and the red is that it turns out that this a list of the method name so technically exposed using method projections an alias and I'm pretty sure that would fail the most every single why don't worry if you read it actually the method in is nobody does that because that's just the so yeah there's no actual be backed up by like August everybody uses and do this back in that they're not that to have a perfect sure steps that like really just captures the epistemology believe perfect projection information when it's like the heat up with reality of so it has a lot of times than an axis on which apparently planning actors orders orders like fighting words because I mentioned that earlier and somebody and you also know that we need that like that's really important and it doesn't matter mind because is actually wise of so they they don't have an automated but it stands a lot of time document axis order the BN it from a different production and axis direction than talks about what the actual projections are but somehow it in these small Taylor discusses that it manages to define multiple projections have seen elites so that several remember land that god comic involved in making it's just them all as LCC because why would you want to have you one-to-one mapping between now and that is and so there is
some multiple conflicting actually implementing on potentially the get as a result there are just like was again from literature was except everything is indeed unusual and this but I and this and this does anybody I don't know why we have a deal like I'm really asking like some of you might know like that that's something that's like about like this but why that media owners were you know there is let alone just is and so this or
that ring when I was working for the Boston Massachusetts and your tax dollars hard at work because my boss is to go indication for months on end and forget to give me the thing to as the union so as the problem because alike between the so we have a lot of Andre talk about from now on the receiving end of getting like a working version that will given a project will likely correctly projector stuff like most of them will probably
like it's not necessarily test projections because we're not done yet like this is the beginning the essence of so this
projection and I think that's actually this bird all life when you go to the PSG that I it it gives you a a well in Texas with only withholding only work health and but it gives you a so marked for the to for for the product code but on the dock conditional French and that 1 of so for what the documentation link did file is all old in French and the common but so I'm not have a job but we have just choose people is a very a very excited work when like I have a demo at the system might ask questions about but so the
next step that I would you want do to travel like improve it would be to pull out that well text parser but this just had that directly immediately delight test against the the light OK this as we will in Texas actually doing the same thing as this kid is 1 is positive and so that actually test that's done in the meantime and not have and not have the so such as weirdness there on the right in
theory that would be great have something standardized like it's like it's seen new duties on a production stuff but but then the person that you like that 5th thinking said that there was sort of the purpose of images images
but in the end again on that's that's and protecting to so the
or like you the user obscure projection could get on to help us out to being shocked shocked us said that you know check so that doesn't work all and all the directions but we collect does work like began issuing of mixing 1 but yes there a lot issues of combatants being a what encoding into it by that's that's a that's a character encodings you that's a time for different time but they're not safe word God you're going but the but the tricky the
but I the thing that you really lacking in to production information is of test vectors bayesian I think it would be like a map projection is correctly because currently like sometimes there's a kind of poverty elaborate and
at so you're to what is you know we got is reliable brought for J is is 1 but since year's agrees with us so I think Europe voted on probably not so that's the general idea here to what is you know what I mean is that 3 India Jesus like test vectors of each sign as it the the the GML files is like the are thousands of things in but and it's pretty hard so to have some data like that that is you're going to here converges in the box you know using this of Caribbean projection that uses lenses submitted you know enough quite do that right because it usually addresses is mine but the
and they think you you have a question if I want to have examples of some of the projects and that is you could use a this physicist this cases where the open up a if you have in the light of place and the date of format and then this light posting on get how business you are like I just sort of like how that we don't have well that that's the question and the the the performance of the we have days we value laden with body deduce on but we are going to like test vectors of reduce the hand to the cells of like OK there will Viterbi-like approach for a while and he this you know production we get this terms and that 1 so all this but as the test probably right you know politically informed that so yeah Jason Bourne by the best of but these are getting a lot of them we might try to like streamlined to make it easier the main obligations and work on the other FIL than the more questions 1st to tell them but OK so thank you we conclude
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