MapWinGIS 4.9 - When opening NED elevation data in GeoTiff format, the Grid class does not provide a projection using the Grid.Header property. GridHeader.Projection() returns an empty string (""). GdalInfo.exe confirms that the projection is contained within the image.
I know that changes were made to the Grid class as a result of issue number # 25742 :
Developer Comment : "However this one was valid (projection is copied correctly now):Only OGC WKT Projections supported for writing to GeoTIFF"
Was this previous issue fixed in response to no projection info being set? Is it fixed now? If I get the latest version of the OCX (4.9.3), will it require any special steps to integrate it into my existing C# application project without breaking it due to version differences?
Thanks!
Comments: Hi, I examined the current code and tested some tiffs. I wasn't able to reproduce it: header returns the same string as GdalInfo (built-in version in Utils class). However the thing that I don't like in current implementation is that WKT projection read both from GDAL dataset itself or from external .prj file is converted to Proj4 for temporary storage within GridRaster class. After that when GridHeader is requested, GeoProjection object is initialized from this string. From my point of view this WKT -> Proj4 conversion is totally needless. Also the reading of projection from external file on grid opening is a bit messy, some cleaning is needed. Regarding latest changes, GridHeader.GeoProjection property was introduced and GeoProjection class is now used to read projection from underlying GDAL dataset (the same technique is used for Image class). Could these changes introduce new bugs - who knows. I need a test data to find out. Can you provide a sample file, so I can reproduce the issue? Thanks, Sergei
I know that changes were made to the Grid class as a result of issue number # 25742 :
Developer Comment : "However this one was valid (projection is copied correctly now):Only OGC WKT Projections supported for writing to GeoTIFF"
Was this previous issue fixed in response to no projection info being set? Is it fixed now? If I get the latest version of the OCX (4.9.3), will it require any special steps to integrate it into my existing C# application project without breaking it due to version differences?
Thanks!
Comments: Hi, I examined the current code and tested some tiffs. I wasn't able to reproduce it: header returns the same string as GdalInfo (built-in version in Utils class). However the thing that I don't like in current implementation is that WKT projection read both from GDAL dataset itself or from external .prj file is converted to Proj4 for temporary storage within GridRaster class. After that when GridHeader is requested, GeoProjection object is initialized from this string. From my point of view this WKT -> Proj4 conversion is totally needless. Also the reading of projection from external file on grid opening is a bit messy, some cleaning is needed. Regarding latest changes, GridHeader.GeoProjection property was introduced and GeoProjection class is now used to read projection from underlying GDAL dataset (the same technique is used for Image class). Could these changes introduce new bugs - who knows. I need a test data to find out. Can you provide a sample file, so I can reproduce the issue? Thanks, Sergei
