Extract informations from a latitude/longitude value

[cgendreau]

This would be done using PostGIS and one or more shape file.
Possible shape files:

• http://www.naturalearthdata.com/
• http://www.diva-gis.org/gdata

We should get at least stateProvince, country and continent as result.
Still TBD for a waterbody.

We do not plan to use an external service due to the limit of request we can do.

[dshorthouse]

NaturalEarth shapefiles were too simplified for the kinds of coordinate validation routines I executed for a few Canadensys participants. DIVA-GIS was more useful for coordinates near shorelines, on small islands, etc. but still resulted in some false positives.

[peterdesmet]

For Canadian and US provinces, isn't there a good national provider for this kind of data?

[dshorthouse]

You would think so. We went fishing for one but cannot find anything. This looked promising, http://geocoder.ca/ but the API provides closest jurisdiction, which means on land/off land information is not produced.

[dshorthouse]

speciesLink, http://splink.cria.org.br/tools?criaLANG=en has a nice set of tools. They use GADM, which is equally useful for the above, http://www.gadm.org/country

[peterdesmet]

Didn't know about http://www.gadm.org/country: thanks for tip. There must be several open geodata portals (software like Tilemill, Mapbox and CartoDB link to a few), but I don't know how precise the datasets are. You would assume national providers have the best data, but it's appalling how few of these are open. GBIF is checking coordinates (for countries + territory waters): maybe worth to ask what they use?

Tip: I recently discovered QGIS, an open source tool to view and edit shapefiles (e.g. changing the datum).

[cgendreau]

They used http://www.naturalearthdata.com/ in the past. As for today, I will let them answer since I don't know.
cc @lfrancke

[lfrancke]

Yes we're still using Natural Earth data as well as EEZ data. Both of them are not perfect and we have some "holes" in the data which leads to misclassifications. We'd be happy for a better source too.

OpenStreetMap data could be a good source: http://openstreetmapdata.com/data