How to tell SharpMap to display polygons based on z-order?

Question

I have a series of polygons which overlap in spatialite. Each has a an attribute providing it's z-order as well as the output color for that polygon. What do I need to do, processing-wise, to allow SharpMap to display the polygons based on z-order, along with the proper color for each polygon, all in a SINGLE layer?

Answer 1

You would first need to tweak the SpatiaLite provider by either

• add a OrderBy property and apply that to the relevant queries (GetGeometriesInView, ...), or
• update the provider to handle spatial views correctly.

Then you need to apply a custom theme setting assigning the appropriate color in respect to ZOrder.

Why don't you want several layers?

Hth FObermaier