Raster GIS Lab: Map Algebra

Download lidar data for the North Carolina coast near Duck.  This will be a 160 MB download with a series of grids. 

Go to the NOAA Coastal Lidar site, and see if any newer Lidar data covers this area.  If so, download it using the graphical download option.  Find when it was collected in the metadata, and create a grid to match the other grids. Lidar point clouds can have high (say a bird that caused a return above the ground) or low values.  You can use percentiles when you display the grids to eliminate a few random points.

Get the TIGER  EDGES (under Features, all lines) file for Dare County, NC, which includes this area.

Deliverables, in a single Word document:


You will create a number of new grids.  You can save these to reopen later (name them carefully, and remember where you saved them), or just recreate them as needed.

New DEM and Open just the 2008_NOAA_IOCM data set.

New DEM.  Close everything, and open just the 2008 and 1997 DEMs.

Make a new grid with the data from the NOAA web site.

Open all the DEMs.  Insure that you only have the DEMs open, and not any of the derived grids.

You might want to look at this area in Google Earth, or try the WMS map overlays to help with your interpretations.  Export options on the Right click on the map popup menu, which can show the location in Google Earth, or USGS TNM viewer high resolution imagery.


We will not look at the Crab data this year, but you could look at it, and it is an interesting data set showing changes in the nearshore environment over time.

Download the beach survey data for the year assigned to you.  From the surveys in this file, take the closest one to the Lidar survey grid for your year.

Coastal survey time series


Last revision 4/29/2017