Visualizing Topography

Visualizing Topography

Having climbed and hiked in Yosemite Valley on numerous weekend trips during college I wanted to capture the iconic topography in a 3D model. With the end result in mind, I ventured into the rabbit hole of publicly accessible data and open source or free GIS and CAD software. USGS terrain data, Google Maps terrain, QGIS, SketchUp, Rhino Cam, and heavy Googling eventually combined and a CNC ready model was exported. Birch plywood was milled with a CNC router and model was sanded and finished with light stain.

USGS EarthExplorer Data was downloaded and viewed using QGIS, a free and open source geographic information system, and vertices were extracted with corresponding elevation values and exported to a .csv file. Importing the .csv file into CAD software was very problematic with the large number of data points and the GIS date projection made appropriately converting and scaling the latitude, longitude, and elevation data into x,y,z coordinates challenging.

A new approach was to use the terrain that can be imported from Google Earth Into SketchUp. Terrain snapshots were layered together to cover the entire Yosemite Valley and the resulting mesh was a relatively detailed model of the terrain. The SketchUp Mesh was exported to RhinoCam, available for free in a beta version on Mac, and was cleaned up and made into a solid suitable for export to CNC milling path software.

I found a custom CNC shop willing to take on the project and layers of Birch plywood were selected for surface appearance and for the lack of voids in the layup. A 1/8″ ballnose bit was the smallest bit available that was able to reach the depths needed to mill the model as a single piece. The resulting carving was sanded smooth and finished with a Danish oil to protect and enhance the appearance of the ply’s that mimics topographic lines.

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