I once wrote a Lisp routine for AutoCad that read the numbers in such text entities and drew a vertical line to the corresponding height at the location of the texts. That could then be imported into SketchUp and a terrain mesh added with the Sandbox from Contours tool. I remember posting it but couldn’t locate it so it could have been at the older Google-based forum. I don’t have it in my laptop but I can re-post it when I go home tomorrow or on Sunday.
Edit: found it. Here it is, zipped, as .lsp is not a supported file type TXT23D2.zip (633 Bytes)
Anssi