Adding building footprints to DEM

[BlairCampbell]

Hi,

I am a student learning Arcmap 10. For our project, I need to add a building footprint raster layer (with heights set to 10 m) to a DEM of the South Island of New Zealand. I have managed this with the raster calculator, except that on the combined raster dataset areas outside of the footprint locations have a no data value, while point locations (the buildings) show the DEM height + 10 m (which is good).

I am wanting the output DEM to also have values (from the native DEM) where there are no buildings. I have seen something about IsNull and Setnull etc but I don't understand this, and am not seeking help from my tutors 🙂 The goal is viewshed analysis. Any help with the syntax appreciated.

Cheers,
Blair

[BlairCampbell]

I found an answer here posted by Crystal Dorn
http://forums.esri.com/Thread.asp?c=93&f=995&t=216232

I needed to set my no data to zero, but could not classify my buildings layer because the high and low values were both 10 m. Setting one building to a value of 1 so I had some range in the data allowed me to reclassify!