Lab 7

The goal of this lab was to become familiar with stereoscopy and orthorectification tasks on satellite and aerial photographs. This included creating an anaglyph to observe elevation features in the Eau Claire, WI region and collecting GCPs to create tie points.

Stereoscopy:

Methods: To become more familiar with stereoscopy, I created an anaglyph image of the city of Eau Claire, WI. I did so by running a digital elevation model (DEM) of the region through the Anaglyph Generation tool in Erdas Imagine 2013. I then observed elevation features.

Results:

The anaglyph showed regions of high and low elevations such as valleys near the Chippewa River or Halfmoon Lake and areas of high elevation on the UWEC campus hill. All elevation shifts seemed to be more dramatic than in real life.





Anaglyph of Eau Claire, WI. 


Orthorectification:

Methods: I orthorectified SPOT satellite images by collecting GCPs (with the classic point measurement tool) on two reference images using the LPS tool. 9 GCPs were collected using the first horizontal reference image and 2 GCPs were collected from the second horizontal reference image. Vertical reference information was collected by using a digital elevation model image and updating the Z values on the collected GCPs. More GCPs were collected on another reference image according to the GCPs already collected after running the DEM and Z values. A triangulation was then run on the two satellite images being orthorectified.

Results:

 The resulting photograph was an accurate spatial boundary between the two images with very little skewing.







Orthorectified SPOT satellite images

Sources:
Wilson, Cyril. (2014). Geog 338: Remote Sensing of the Environment Lab 7 Photogrammetry. Personal collection of  Cyril Wilson, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin.