SO503 Spring 2009

Lidar Mapping Lab

Open MICRODEM, which you can download from http://www.usna.edu/Users/oceano/pguth/website/microdemdown.htm .

• If you do not have version 2009.2.18.2 or more recent, go to  Files, Tools, Close Program and Update.
• If you had to update the program, also update the help file; go to Files, Tools, Update Help file.
• If there is not a directory c:\mapdata\duck_beach, go to Files, Tools, Download data sets,  and pick Duck LIDAR and profiles
• If there is not a directory c:\mapdata\montana_lidar, go to Files, Tools, Download data sets,  and pick Montana LIDAR

Data sets:

• Coastal lidar from NOAA.  There are 9 surveys of the coast from http://maps.csc.noaa.gov/dataviewer/viewer.html
• Montana lidar, both bare earth and first return.  This is from http://calm.geo.berkeley.edu/ncalm/index.html

For detailed directions, look in the MICRODEM help file, table of contents, Tutorials and labs, Lidar examples.

Duck, NC. 

• Draw multiple profiles to compare the 2004, 2005, and 2008 Lidar data sets from Duck.  How does the offshore/underwater region differ for these three data sets, and what does that say about the lidar sensor used for each survey?
• Do a difference map for two of the data sets.  Where are the largest differences, and do you think they are significant in terms of beach processes?  You may need to adjust the color scheme to clearly show what is going on.
• Include at least two figures to support your answers.

Montana

• Compute a grid with the vegetation heights, which is the difference between the first return and the bare earth.. 
  • If you do the difference in the wrong order, you can multiply the values by -1 on the edit menu. 
  • What is the distribution of tree heights, and do you think these values are reasonable?  The Analysze, histogram may help with this.  Consider both the signs and magnitudes of the
  • Where are the extreme values? (Calculate, Elevations, Extreme) can show you their spatial patterns.
  • Remove what you would consider to be excessive tree heights.  You could make them missing, or do single grid arithmetic, both on the edit menu.
• Get a stream profile, using the bare earth DEM, of the large stream in the center of the data set.
  • You could use the Calculate, Stream profile option.
  • You could alternatively create a line shape file, and then create a profile from the database associated with that

Turn in a discussion of the questions above to the course drop box by 0800 on Thur 26 Feb 2009.