Maestro: Warn user when adding a raster layer to a map with a different coordinate system

[jbirch]

Currently, when adding a raster layer to a map that does not have a matching coordinate system, the layer rendering will fail with an exception logged on the server. In the future (post RFC 51) these layers will work, but with a performance penalty.

Given the impact of adding a raster with a mismatched coordinate system to a map, it would be useful if Maestro could test the coordinate system of the map against the coordinate system(s) / overrides of raster layers, and warn the user when they differ. I believe that this would have to be applied against the GDAL provider, the Autodesk Raster provider, and possibly the WMS provider.

[tomfukushima]

Good idea. And yes, those are the providers that we know aobut that will need to be checked. However, it should be possible to check if the feature class is a "raster" class (ie, Layer is a GridLayerDefinition) and then display the warning for that. This will allow us to catch things like Oracle rasters or raster providers that we don't currently know about which may be added in the future.

[ksgeograf]

Yes. Nice idea. It is indeed possible to detect if the layer is a raster. There will be a small overhead when adding the layer, due to a call to "DescribeSchema" for getting the coordinate system.

I will also add a check to see if the extent reported by the provider is the (-1000000,-1000000,1000000,1000000) extent, which is sometimes a masked error, and in any case, not likely to be a valid bound.

[ksgeograf]

I have added the resource validator which will inform the user of coordinate system issues, so I won't implement this.

Feel free to discuss if you disagree.