Terrain Modeling at Waubonsie State Park, Iowa

Not every GIS analysis or design scenario occurs on flat land, y’know.  So I’m taking a break from head banging on CGA code analysis and delving into another topic, pulling DEM data into CityEngine and building models on terrain.

Here, I will introduce the subject area I frequently use in terrain experiments, Waubonsie State Park in Fremont County, Iowa at the far southwestern corner of the state. It is a favorite of mine because there's a lot going on in a space of only 1,990 acres and it is less than 90 minutes away when I need to ground truth; it's always nice to visit project locales.

The park is situated in the hills and rock bluffs that line either side of the Missouri River flood plain. This "envelope" around the flatlands is apparent when you drive Interstate 29 south from Omaha, Nebraska. Exit I-29 at Highway 2 just north of the Missouri state line and you'll see the hills about 5 miles to the east. The elevation at the foot of these bluffs is around 900 feet (275m) ASL. Once inside the park, the terrain rises and you are suddenly immersed within a crinkly relief of loess hill woodland.  The highest elevations are around 1282 feet, 391 meters ASL.  There are 15 miles of hiking and equestrian trails including the Sunset Ridge trail, that begins with a ~150-foot elevation drop across the first 1000 feet from the trail head. There are cabins, campgrounds, restrooms and other facilities that offer a great exercise in creating feature classes and mapping.

Waubonsie State Park was my laboratory when I did my first experiments with LiDAR, which involved downloading and rendering data from the Iowa LiDAR project, then visiting Waubonsie to see how the model compared with the real thing.  And so my CityEngine experiments will begin with the same data, a 10m DEM raster and a shapefile of roadway centerlines.

Distant hills: 40.645154, -95.697375

Drainage ditch: 40.651710, -95.696084

Dam and spillway: 40.661225, -95.687139

Dam and spillway: 40.661225, -95.687139

Behind the dam: 40.661753, -95.686684

Spillway: 40.661225, -95.687139

Park roadway: 40.664638, -95.686661

Split roadway: 40.675001, -95.689739

Road w/mound: 40.670364, -95.689043

Restroom Building: 40.670022, -95.689404

Restroom Building: 40.670022, -95.689404

Sunset Ridge trailhead: 40.667244, -95.695178

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