How to Extract Data from U.S. National Landcover Dataset (NLCD) dataset?

Question

I am working with U.S. National Landcover Dataset (NLCD) to classify habitat type at more than 150 sites across the northeast U.S. The dataset is very large (15GB) so I cannot upload it here, but it comes in .img format at 30m resolution. I have GPS coordinates in decimal degrees (WGS1984) for the center point of all the sites. I would like to be able to extract the proportion of landcover classes in a 1 square kilometer around the point. My questions are:

1. How do I upload .img files into ArcGIS?
2. How do I extract the information from around the GPS coordinates as proportions of the different habitat classes?
3. How do I project my sites onto the NLCD map?
4. Should I change the projection of my coordinates?

Answer 1

I would try something like the following as a loose workflow:

• a) buffer around the points (arcmap has a flat option to get 1km^2).
• b) merge those into a single feature class to overlay on the whole map.
• c) use the results from a) to clip tiles from the NLDS to find the data present.
• d) compile the results from c).
• e) compare results from d) to the whole map.

This assumes that you would be okay with a bit programming.