Cad underlay, with Adobe photoshop for colors and Adobe illustrator for lettering / type
This looks like it could be an Adobe Illustrator drawing. Illustrator can import AutoCad .dwg and .dxf files. AutoCad (assuming it's the source of the original subdivision plan) can also export Postscript (.eps) files, which Illustrator and some other drawing programs can import.
Question regarding this graphic:I do these regularly. CAD base rendered in M-Color.