[OSGeo-Discuss] Detect and define the coordinate system of gis data with no projection information automatically

[Even Rouault]

Foks,

I read through the emails of this thread and I'm still not sure to understand 
what the exact focus would be. It seems it might go beyond the title of this 
email thread.

Is it about documentation about projections ? If so, I guess improving proj.4 
documentation could be appreciated. There has been a new commit just last 
night ( http://lists.maptools.org/pipermail/proj/2016-September/007480.html ) 
to add the chart of each projection :
http://proj4.org/projections/index.html . There are only images extracted from 
ftp://ftp.remotesensing.org/proj/OF90-284.pdf for now but that would be great 
to extend them with formulas, etc...

Is it about having a catalog of spatial reference systems (and all related 
information: projections, projection parameters, ellipsoids, datums, prime 
meridians, area of use, transformations, etc...) ? Then there are different 
projects already tackling that. For example GDAL starts with the EPSG catalog 
+ some algorithms to detect one of the many datum shifts to WGS84 (this part 
is controversial and could/should be improved), and that is the source from 
which the proj.4 'espg' catalog (the whole process is documented at 
https://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/README). This process 
is a bit cumbersome and we had some discussions last year about perhaps 
adopting a SQLite3 database instead (see thread starting at 
https://lists.osgeo.org/pipermail/metacrs/2015-August/000846.html) : this 
hasn't made progress yet.
GDAL has also a few extra catalogs from (somewhat old) ESRI definitions, and 
other vendors. There are also catalogs for SRS of other planets : 
https://trac.osgeo.org/gdal/ticket/6623 (interestingly Peter Baumann 
mentionned that the EPSG service might host this catalog in the future)
A tricky part about all this catalogs is the intellectual property behind as 
there are often not completely "free" in the meaning we generally give to that 
term for software (redistribution is OK, but most often modifying definitions 
is not allowed). But beyond that, as raised by Carl Reed, adding new spatial 
reference system definitions, or editing existing ones, is something that needs 
some form of validation at some point (unless you decide that anyone can 
modify anything, but that opens the door to voluntary or unvoluntary mess). It 
is similar to when someone submits a patch/pull request for code: someone 
needs to make a decision if it is appropriate or not.

You've also identified spatialreference.org (now somewhat abandonned due to 
lack of volunteer) or epsg.io as online catalogs. I see also 
https://github.com/ebrelsford/projestions#api that has been mentionned. 
Perhaps one or several of them of those could be used as the base to build 
something new above ?

Probably that the MetaCRS list could be a more appropriate and focused place 
to hold such further discussions ? 
https://lists.osgeo.org/mailman/listinfo/metacrs

Unrelated: I read a few confusions in this thread with "OSGeo members" vs 
"OSGeo charter members". Quickly summarizing http://www.osgeo.org/membership: 
anyone can declare himself as a OSGeo member by registering himself on 
https://wiki.osgeo.org/wiki/Special:RequestAccount . OSGeo charter members are 
members who are elected, for the only additional purpose of electing the OSGeo 
boards. There are also OSGeo participants who are anyone that takes part to 
OSGeo related activities. Projects are generally open to contributions from 
anyone, with some kernel/PSC (not necessarily made of charter members) taking 
the main decisions.

Best regards,

Even

> Hello,
> 
> At FOSS4G 2016 in Bonn i talked with Venkatesh Raghavan about my poster
> presentation "SHAPEFILE PROJECTIONFINDER". URL to poster:
> http://www.egger-gis.at/app/download/13175253496/POSTER_EGGER_FOSS4G.pdf?t
> =1469787116
> 
> He recommended to start a discussion in this mailing list about the topic
> mentioned in the mail subject.
> 
> I also talked in Bonn with Petr Pridal about http://epsg.io. Some days
> before Bonn i wrote emails to Aaaron Racicot and the mailing list of
> http://spatialrefrence.org.
> 
> Please read first carefully on my website, what i plan to do:
> 
> http://www.egger-gis.at/shapefile-projectionfinder/
> 
> There are two problems to solve before tools like SHAPEFILE
> PROJECTIONFINDER can be developed as a sustainable solution:
> 
> 1. Until today there is no stable free service running like
> www.projfinder.com by Aaron Racicot, which can be used by all developers.
> 
> 2. Until today there is no open source database which includes all
> coordinate system with epsg-code and additionally user and esri definded
> grids.
> 
> There are open source solutions like:
> 
> - spatialrefrence.org
> - epsg.io
> 
> But in the detail both solutions have problems to update their database
> with low costs.
> 
> Maybe OSGeo can promote a stable service with load balancing on the base of
> an existing solution like epsg.io including Aarons idea?
> 
> Maybe organisation like UN, a university or EU (INTERREG) are possible
> project partners/sponsors for such a solution?
> 
> The goal is: Tools like SHAPEFILE PROJECTIONFINDER, a Q-GIS-Plugin or a
> mobile application can use a stable free gis-service updated daily and
> help gis users to solve projection troubles faster. I think gis users
> working not everyday with gis will be happy about this solutions?
> 
> What do you think about my idea?
> 
> Best regards,
> 
> Manfred Egger
> 
> Alois-Schrott-Str. 34
> 6020 Innsbruck
> Austria
> 
> Web: http://egger-gis.at
> 
> _______________________________________________
> Discuss mailing list
> Discuss at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/discuss

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com