acrotron.com 

A .NET library for generating contour lines and polygons from scattered geospatial data using triangulation-based interpolation.

Contour line and polygon generation from raster grids using the Marching Squares algorithm. Subdivides raster cells into sub-triangles via bilinear interpolation and traces contours through the resulting mesh.... More information

A .NET library for reading and parsing Esri ASCII raster (.asc) files, with optional coordinate transformation support.

GRASS GIS v.surf.rst spline interpolation (Completely Regularized Spline with Tension). Reimplemented in C# from GRASS GIS source code.

A library for parsing AEDT (Aviation Environmental Design Tool) files, including bounding box and receptor data extraction with spatial geometry support.