Land Cover Analysis of Jackson Hole, Wyoming By David Zubenko
Introduction For my project I chose to focus on the continued development of Jackson Hole, Wyoming. The local economy is based heavily on tourism, and since the 1980s the town has expanded to accommodate an increasing number of visitors. To become acquainted with the town, please see the overview map and orthoimages below. Overview Map
Orthoimage
Imagery To better see and understand this change I acquired Landsat 4-‐5TM imagery from 1986 and 2011, the widest range available. Once I brought these images into ArcMap I clipped them down to Jackson Hole and the surrounding area. 1986
2011
I also acquired DEM elevation data and manipulated it into a hillshade. Screenshots of each, cut to the project boundary, are below. DEM
Hillshade
Analysis I began the analysis portion of the study by running a 5 class ENVI unsupervised land cover classification. Although there is obviously a difference between 1986 and 2011, it was difficult to assign labels to each class. In particular, the yellow class did not seem to correspond to anything. Using my knowledge of the area, I ultimately concluded that yellow corresponds to the nature preserves where elk and other animals eat the grass, making it shorter than the normal grass found in the dark blue areas. The fact that the yellow is often found next to light blue (bare earth) helps to confirm this hypothesis. 1986
2011
I also ran 10 and 15 class ENVI unsupervised classifications, but did not find these as useful. For the sake of completeness they are included below. 10 Class, 1986
10 Class, 2011
15 Class, 1986
15 Class, 2011
In addition, I ran the Iso Cluster tool in ArcMap to create 5, 10, and 15 class land cover classifications. Again, the 5 class version was the most useful and it matched up well with the corresponding ENVI classification. 5 Class, 1986
5 Class, 2011
10 Class, 1986
10 Class, 2011
15 Class, 1986
15 Class, 2011
After “filling” the DEM I continued my analysis by running the slope, aspect, flow direction and flow accumulation tools for the study area. Slope
Aspect
Flow Direction
Flow Accumulation
Final Conclusions In the end this project resulted in mixed conclusions. Although personal experience and visual interpretation of the data seem to suggest a growth in urban development, many of the tools in ArcGIS and ENVI suggest otherwise. Below are the ENVI change analysis and pixel classification for the 25 year period. ENVI Change Analysis
Pixel Classification Both the ENVI and Iso Cluster classifications show a decrease in Class 2 (Buildings/Pavement), an increase in Class 3 (Normal Grass), and a decrease in Class 4 (Shorter Grass). These results were somewhat unexpected and contradict general knowledge of the area. ENVI, 1986
ENVI, 2011
Iso Cluster, 1986
Iso Cluster, 2011
In regards to the visual interpretation of the data, most development seemed to occur south of town. This area is rather flat, as illustrated by the hillshade and slope analysis, making it conducive for growth. Visual interpretation also suggests some growth around the town itself. The ancillary data proved particularly useful in making these determinations. I was unable to determine why there was an increase in “normal grass” and decrease in “shorter grass”, and this is something I would focus on if I had more time. Although this project was challenging, it was also very rewarding and a great way to end the course.
Data Information Landsat images were acquired via Earth Explorer on 12/6/13. They have a GSD of 30 meters and radiometric resolution of 16 bits. Once in ArcMap they were converted from WGS 1984 to NAD 1983. The DEM was acquired via National Map Viewer on 12/4/13. It has a radiometric resolution of 32 bits. A GSD is not available. Once in ArcMap it was converted from GCS North American 1983 to NAD 1983. The orthoimage was acquired via National Map Viewer on 12/4/12. It has a GSD of 1 meter and radiometric resolution of 8 bits. It was already in the NAD 1983 coordinate system and did not need to be converted.