Week 13 -GIS - Georeferencing and ArcScene

Georeferenced Aerial Imagery of UWF Campus

In this week's lesson, we learned how to georeference an image with no coordinate system to an existing vector file.  In order to do that, we matched points on the raster air photo to the same points on the vector file of UWF buildings.  By locating matching at least ten easily-identifiable points from the two files, such as the corners of buildings, the Georeferencing tools in ArcMap make it pretty straight-forward to stretch and adjust the raster image to fit over the vector polygon features.
The RMS Error is a measure of the accuracy: a number below about 15 is acceptable.  In this example, I managed to get the RMS errors down to between 3 and 5.  What's most important, of course, is that the features on the raster visibly line up with their counterparts in the vector shapefile.

In the second part of this exercise, we used ArcMap to digitize a building and a road that were not previously part of the polygon and linear vector shapefiles.

The upper unset map to the right shows the location of an eagle nest that is being protected by a buffer zone in which no new development can take place.  There is a .jpg photo of the nest located in the attribute table of the .mxd, for the point representing the eagles' nest (below).  This photo can be opened from within the ArcMap .mxd, using the Information button.

An Eagle Nest near the UWF campus

In the second part of this week's lab, we used the ArcScene prohgram to create an oblique, 3D image from the UWF campus map that we earlier georeferenced with the aerial imagery.

To do this, we "draped" the raster imagery and the vector files of buildings and roads over a Digital Elevation Model (DEM) of this area.  Because the height of each building is contained within the attributes of the Building vector dataset, we could instruct the ArcScene program to add the height of each building to the ground elevation (with 5x exaggeration to help visibility), and thus have a 3D picture of the buildings on the campus.