The geologic and geomorphic data contained within this data base were originally obtained for 1:2,000,000 digitized line segments. These line segments ranged in length from 93 m to 88.7 km and averaged 5.8 km in length. When plotted, these line segments are equivalent to those found in the line- based data groups within this NDP. When gridded, more than one line segment often occurred within a coastal grid cell. When this situation occurred, the geologic or geomorphic code with the greatest total shore length within the grid cell was assigned to the entire grid cell. For example, if grid cell number 396 contained two line segments, the first having geomorphic code 2255 and covering 36.86% of the shore length within the grid cell, and the other having geomorphic code 2450 and covering 63.14% of the total shore length within the grid cell, then geomorphic code 2450 was assigned to the grid cell, along with its corresponding risk value of 3.
To help the data user determine how this selection process may have affected the gridded data, the following tables were constructed. Table C-1 illustrates the geologic data. It contains the identification number of each coastal grid cell, the occurring geology codes, the shore length (in meters) in each occurring geologic code, the percent of shore line with the occurring geologic code, and the risk value of the geologic code. Table 1, in part 1 of this document, defines each geologic classification code while Table 4 illustrates the relative risk value assignment. Table C-2 illustrates the geomorphic data. It contains the identification number of each coastal grid cell, the occurring geomorphic codes, the shore length (in meters) of each occurring geomorphic code, the percent of shoreline with each code, and the risk value of the geomorphic code. Table 2 defines each geomorphic code and Table 5 shows the ranking system used for assigning the relative risk values.