Lab 3 - Land Use / Land Cover Classification Mapping

This week we got to try our hand at classifying an aerial photograph.  Using a Land Use Land Cover classification system, which was developed in 1976 by Anderson et al. for the USGS, we classed a single aerial photo to the second level.  My minimum mapping unit (MMU) was at 1:4,000. 

Aerial map showing Level II Land Use and Land Cover Classification.

What does all this mean, exactly?  To start, land use is a bit different from land cover.  Land use shows human-based uses of the landscape (urban areas, agriculture), and land cover shows primarily natural settings (forests, water).  To classify a map one first needs to differentiate between farmland, urban areas, forested areas, etc.  That is a primary classification level.  To map something at the second classification level is to specify if, for example, the areas within an urban area are for residential use versus an industrial use.

The map above shows various classifications within a small section of Pascagoula, Mississippi.  For consistency I had digitized my classification polygons at the 1:4,000 level only.  While I may have zoomed in or out to double check on a classification type or my overall location on the aerial photo, when I digitized an area it was always at 1:4,000 (also known as my MMU).

Completing this map was a bit rough at times - occasionally I felt like I was adding to much detail, and other times like I wasn't adding enough.  Since a Level II classification is meant to be a bit coarse perhaps my biggest lesson was in learning to let go of the details!  For example, a high-tension wire crosses through the lower left of the aerial photo.  This was not mapped in mainly because to do so would have been very difficult given the level of detail that it would require... if my MMU was a bit larger then perhaps it would have been possible, however I would also probably still be working on this map!

Reference:
Anderson, J.R., and E. E. Hardy, J.T. Roach, R. E. Witmer
1976     A Land Use and Land Cover Classification System for Use with Remote Sensor Data.  Geological Survey Professional Paper 964.  United States Government Printing Office, Washington D. C.