LULC Analysis

This week's assignment in Remote Sensing focused on land use/land cover analysis of an aerial photo.  Our job was to analysis apparent land use and classify it according to a USGS two-level classification code.

The map seems to have two main “super-areas” – the bay and the urban land.  I began by creating a polygon for the whole bay (the shore and frame edges).  I then created a series of polygons for the wetland islands.  Later I would “erase” the bay with the islands to create a shapefile that was just the water areas of the bay (avoiding polygon overlap).

In the urban region, I began by identifying “natural” areas like the rivers, estuaries, lakes, and small forested areas. There didn’t seem to be any agricultural areas in this photo. These natural areas were pretty easy to identify, though I could see some difference of opinion on forest types and various classifications of wetland, estuary, and streams.  Similar to how the islands were handled in the bay, the deciduous forest was “unioned” and then the lakes “erased” so that the forest and lake polygons wouldn’t overlap.

Next, I started classifying the urban areas.  Several of these were quite easy to identify after the lecture and text descriptions – industrial areas, schools, and retail areas.  I was also quite happy to recognize the cemetery in the lower right.   The most difficult was the area I classified as “Commercial and Services” region that borders the highway.  There is quite a mix in there and some may even be residential.

Finally, everything that wasn’t otherwise classified in the Urban region, I deemed “Residential”. This is all the single residence housing that fills the urban region. To create this region I used the Urban Land polygon and “erased” a union of all the urban classified sub-regions out of it.