Week 13 - Georeferencing, Editing, and ArcScene

Unfortunately, the end to this semester is near -- so for this week's lesson we began to wrap things up by discussing 3 major GIS topics: georeferencing, editing, and ArcScene.

Georeferencing is the process of finding and linking common points in a scanned document to real-world coordinates. A lot of major GIS data is created by looking at imagery that has already been georeferenced. We were able to explore this by the activities presented in our lab assignment. First off, we were given 2 imagery photographs (uwf_n.jpg and uwf_s1.jpg) of the University of West Florida's campus, to georefence in ArcGIS since they were missing a spatial reference. Using the Control Points, Transformation option, Fit to Display option, and the View Link Table in the Georeferencing Toolbar, we successfully rectified the imagery to earth's surface, as shown below in my final map product. Through the process, we learned that using about 10 or more control points is a good standard for georeferencing, as well as maintaining a total Root Mean Square Error (RMSE) below 15. Additionally, we practiced polynomial transformation orders. For my map, I was able to achieve Total RMS Errors below 5 for both imagery photos, and used a 1st order polynomial on my north image, and a 2nd order polynomial in my south image.

As aforementioned, we created important GIS data from the imagery we georeferenced by "Editing" (our second major topic). We were provided a file geodatabase, and created/digitized 2 new features in existing feature classes, respectively: a new gymnasium building (depicted as orange in my map), and a new road (called Campus Lane in my map). To create these features we initiated an edit session in each of these feature classes, and used various Editing Tools, such as the Create Features window, Construction tool, Line, Arc, and Snapping.

Also, we learned how to use the Multiple Ring Buffers Tool found under Geoprocessing Tools > Analysis > Proximity, to create 330 ft and 660 ft buffers around an eagle nesting site near UWF's campus. We also learned how to create hyperlinks in feature classes to data stored in a personal drive. In this scenario, we hyperlinked an image of the eagle nest to the eagle nesting site (point feature class); the photo is stored in our personal student drive profile.

Lastly, using the data we created above, we got a little taste of ArcScene by creating a 3-dimensional map of UWF's campus. ArcScene allows us to overlay layers, and configure height information from feature geometry to create a 3D environment. To make this happen, we configured a lot of settings under the Properties > Base Heights window. Additionally, we used a digital elevation model (DEM) file that was originally downloaded from Labins.org which uses meters as its elevation units.