CNMI and Guam rugosity maps are all symbolized with the same stretched color ramp (1.5 standard deviations) in order to provide a standard for qualitative comparisons between islands. Each island has a unique maximum value for rugosity causing the distribution of values across the color ramp to vary slightly. It is recommended that the actual data set be used for integrated analysis in order to make quantitative observations. The values for this data set range from 1.000 to 4.251 with a mean of 1.118 and a standard deviation of 0.133.
The terrestrial elevation data shown in the map for this data set are SRTM Finished 3 arc sec Shaded Relief. They were collected during NASA's Shuttle Radar Topograph Mission (SRTM). For more information on the mission, go to: <http://www2.jpl.nasa.gov/srtm/faq.html#data>. The data are available from the United States Geological Survey (USGS) as reformatted elevation data that are consistent with other Digital Elevation Models.