Edge Enhancement and
Vegetation Change of
the Tampa Bay Region
from 1995 to 2010
Joel Weber Introduction to Remote Sensing December 14, 2014
Introduction


Remote Sensing Analysis








Next, I ran a Normalized Difference
Vegetation Index (NDVI) on the Tampa Bay Region for 1995 and 2010 (Figure 6).
NDVI uses an equation to calculate how much vegetation is in each pixel. The
NDVI equation is
NDVI=(NIR-Red)/(NIR+Red)


Next, I ran a non-directional edge enhancement
technique on images from both years (Figure 7). This process shows where
dramatic changes in brightness values occur in a relatively short distance.
Edges are commonly found along river banks and along roadways. Comparing
non-directional edges from two different years can provide detail about where
new roads are being built and possibly where population is increasing. Figure 7
shows where new roads were 
built in the lower portion of Manatee County as urban sprawl
occurs.


Finally,
I ran a binary change detection between 1995 and 2010 to determine where vegetation
has changed (Figure 8). To determine where change has occurred we simply
subtract NIR brightness values of one image from NIR brightness values of
another image. Then we apply a change threshold to determine whether or not that
area has changed. After the 1995 image has been subtracted from the 2010 image
we use the histogram to determine the threshold. In this case we use 1.5 times
the Standard Deviation plus the mean brightness value. Any areas that have NIR
brightness values above the threshold have changed.
Conclusion
In conclusion, all remote sensing
projects begin with data acquisition, then images must be mosaicked together,
then a subset of the study area must be created. Finally, you are able to run
various analysis techniques. I found that the NDVI values were much lower in
2010 than in 1995 throughout the entire image. This could be caused by urban
sprawl in some areas and differences in crop production in more rural areas. I
also found a large increase in edges that occur in the lower 
portion of Manatee County and other
suburban areas between 1995 and 2010 while areas that are already densely
populated will have similar edges between the two years. This can definitely be
attributed to urban sprawl as populations increase. Finally, the binary change
detection between 1995 and 2010 shows us where vegetation has changed (Figure
9). Very little change has occurred in dense urban areas while significant
changes have occurred in rural farmland and suburban areas.




References
U.S. Census Bureau. (2014). State and county quickfacts: Florida. Retrieved December 12, 2014,
from http://quickfacts.census.gov/qfd/states/12000.html.
U.S. Geologic
Survey. (2014). Global visualization viewer. Retrieved December 10, 2014, from http://glovis.usgs.gov/.