Jennifer Carrell of the Illinois State Geological Survey has written a handy tool for creating geologic cross sections in ArcMap 9.3. This program called Create Geologic Cross Sections–eXacto Section v. 2.0.

The objective of this program is to use GIS to draw important parts of the cross section precisely: the surface profile (using a DEM), the geologic units and their contact points on the surface, the location of wells/boreholes, and the geologic materials found at the well location, projected as a line into the subsurface. The output is a combination of polyline and point shapefiles. One of the advantages of this program is that the output features have a spatial reference, meaning that, when set to the desired map scale, the cross section measurements will always be correct. The geologist can use these as a guide to “connect the dots” when drawing the subsurface contacts. He or she can choose to finish the cross section digitally in ArcMap or export it to a graphics program.

Visual Basic for Applications (VBA) was used to develop the program. Code is stored in the .mxd. The user provides input data: lines of cross section, an elevation raster, geology polygons, well points, and a table with subsurface data. The user defines a sampling interval and vertical exaggeration. The program will convert between feet and meters, depending on the units of the input data. A button control launches a form that obtains the required inputs. The user can choose which outputs he or she wants. The output layers are automatically symbolized and labeled in a new data frame.

The downloadable zip file contains an .mxd, user guide, tutorial instructions, and tutorial data. The user guide and tutorial were created for an older version of the tool and have not been updated.

New version requires only an ArcView License! 3D Analyst extension is still required.

12/23-09: Fixed a few more bugs. New version was tested successfully in 9.3 and 9.3.1.