Sortshp makes invalid shapefile from 3D-polygon source file

[jratike80]

It looks like sortshp utility creates a somehow invalid sorted shapefile as an output if the input file is a 3D Polygon shapefile. I can repeat the error in my environment which is Windows 2003 Server and sortshp from GDAL 1.7.0dev (FWTools 2.4.2).

How to test:

• Take a 3D Polygon shapefile

• do sortshp

• try to convert the sorted shapefile with ogr2ogr

[warmerdam]

I have made the following changes in trunk (r10592,r10953):

• sortshp.c now sets error reporting to stderr (for msSetError())
• sortshp.c now checks msSHPCreate and msDBFCreate return values.
• mapshape.c's msSHPCreate() now issues an error if an attempt is made to create z/m type shapefiles with USE_POINT_Z_M is not enabled.
• mapshape.c's msSHPWrite now correctly writes Z/M shapes if requested and enabled - they were being written corrupted.

I should note that error checking in mapshape.c seems ... lacking, and that support for z/m shapefiles in mapserver has clearly not been tested much.