File Formats:Mapping Tables

Mapping tables are the heart of how parameters are set up in GSSHA. Mapping tables work in conjuction with index maps to create a spatially-defined parameter set. The mapping tables refer to an index map, that has an ID value for each active cell in the grid, and a set of paramters for each id for a particular process. The mapping tables have a defined format, but can have as many IDs as needed or desired. The mapping table is divided into two parts, the header and the tables.

Mapping Table Header

The mapping table file must always begin with the line

GSSHA_INDEX_MAP_TABLES

After that line comes a set of index map indentifiers of the following format:

INDEX_MAP "filename.idx" "index map name"
INDEX_MAP "filename.idx" "index map name"
INDEX_MAP "filename.idx" "index map name"
...

These lines associate a particular file with a name. This name is used in the tables that follow. .idx is the usual extension for the index maps, but it can be anything.

General Table Format

The basic format of a mapping table is as follows:

TABLE_NAME "index map name"
NUM_IDS [###]
ID Description ... Parameter descriptions... (text line)
[##] text goes here... [###.###] [###.###] [###.###] ...
[##] text goes here... [###.###] [###.###] [###.###] ...
[##] text goes here... [###.###] [###.###] [###.###] ...
...

TABLE_NAME must be one of the pre-defined tables. "index map name" must refer to an index map (see above.) NUM_IDS must be the count of the number of table entries. The line "ID Description..." must be present but is merely a text line to assist in manually reading and editing the file. The ID can be up to 6 characters, and the description must start at the 7th character. There are two description fields, each of 40 characters. After that begins the parameter value listing.