Can anyone tell me the best way to combine a surveyed topographical surface into a GIS surface so that I can then get a cut fill with a third grading surface. The problem is not enough surveyed topo, so in the areas that are lacking, I want to use the GIS surface. The survey surface is a maze of road row's that have areas cut out within it. These areas will need to be the aerial topo. When I paste the survey into the GIS, it did not work correctly. There were missing survey topo. Then I tried an outer boundary with hides on the aerial, and then pasted the survey. Better, but not correct, and when I made my cut fill tin volume surface, it did not seem to be correct. Can anyone advise?