Terrain Modeling and Visualization


The CCC has several geologic projects underway including one to study the relationship of surface karst in the Carroll Cave area to the cave itself.   There are several different tools and data sets available for analysis.  Terrain modeling and visualization techniques help us understand and “see” the surface topography.  One goal is to map and characterize the sinks and enlarged joint systems thereby better understanding the relationship of surface drainage to subsurface drainage (Carroll Cave).



Static Displays


The following are static (stationary) displays, which show the topography around Carroll.


The following is a color topo map from the Montreal 7.5 minute quad that has been color-coded:  “hot” colors indicate higher topography while “cool” colors indicate lower elevation.


As a first pass of the detailed surface geology, I have color coded the elevation contours to reflect potential geologic contacts:


(1)    Alluvium- Lower Color Range Green and Blue

(2)    Lower Gasconade- Lower Color Range Yellow ,Orange, and Red

(3)    Upper Gasconade- Upper Color Range Green and White

(4)    Lower Roubidoux-  Brown

(5)    Upper Roubidoux- Upper Color Range Yellow, Orange, and Red




The static displays are powerful to help delineate sinkholes and fracture patterns.


Old Sinkhole Dig




The old sinkhole dig doesn’t show up well on the digital topo, conventional topo maps, or on the aerial photo because it had been filled with trash at the times the maps were made.




                                                                        Old Sinkhole Dig       







If you can get some old red-blue “3-d” glasses (like the kind you used to watch the old monster movies) this display will “pop” out of the screen: a true 3-d image.

Different colors, vantage points, and rotations will highlight different map details.





Dynamic Displays


Model One  (download Model 1 – AVI)


Static terrain models can be animated and then “filmed” to create a dynamic, moving display of the terrain.  The following video is an animation of a terrain model created of the Carroll Cave area.  The “flight path” is marked in red: we “fly” across the cave entrance on the east side of Mill Creek northwest to T-Junction and then west to the Old Sinkhole Dig.





The first frame looks to the northwest across Mill Creek across from the natural cave entrance.  Note the color scale change.  The Alluvium of Mill Creek  is purple-blue, the Lower Gasconade is brown, the Upper Gasconade is yellow, and the Roubidoux is green and red.




About a 1/3 through the video, you can see several sinkholes that standout on the  

dynamic model, that aren’t apparent on the regular topo map.  The T- Junction is where the “flight plan” bends to go west towards the old sinkhole dig.



    Possible Fault


The video terminates just east of the old sinkhole dig.  It wasn’t until looking at the dynamic display that I noted what looks like a major joint or a fault that would be running north-south close to the west end of the cave near the collapse termination of Upper Thunder River (about 1500’ east of old dig).






Model 2    (download Model 2 AVI)



This “flight” is from the mouth of Traw Hollow to the Old Dig to a sinkhole “swarm” south of Montreal.  You can see several large sinkholes along the path and at the end of the run.



If you have any questions about the geology sections, or would like to see some additional geology on the web, please contact Rick Hines, Marty Griffin, Bill Copeland or Morris Hall at