If the user specifies the input file name and (optionally) the zone number or spheroid to be used on the command line, the program will run non-interactively; if no zone number or spheroid name is given, the default(s) will be used (see below). Alternately, the user may simply type m.tiger.region on the command line; in this case, the program will prompt the user for parameter values using the standard GRASS parser interface described in the manual entry for parser.
Available spheroids are:
australian bessel clark66 clark80 everest international wgs72 wgs84
It is recommended that the user choose the clark66 (default) spheroid when dealing with TIGER data as it is the most consistent with the original data.
program output would look similar to this:
Number of calculated zones is: 2
INFO FOR ZONE 1: zone number: 13 percentage of data points in this zone: 0.799489 regional spread of points within this zone: north: 5092049.155918 south: 5049238.983803 east: 734139.517650 west: 732514.747908 INFO FOR ZONE 2: zone number: 14 percentage of data points in this zone: 99.200508 regional spread of points within this zone: north: 5092041.463966 south: 5036134.342322 east: 398030.217441 west: 265527.656108
If the user does not input the UTM zone number, it is calculated for them. Then the zone number and region information are output, and if the program finds that the input data contains information in more than one UTM zone, then the output is given for all applicable zones.
If instead the user supplies the UTM zone number, the output would look like that shown below:
REGION FOR THIS DATA FILE:; north border: 5092049.155918 south border: 5036134.342322 east border: 398030.217441 west border: 265527.656108 (zone number: 14)
TIGER data are presented in latitude/longitude format, and are converted to UTM coordinates using coordinate conversion routines contained in the GRASS library. If no UTM zone number is supplied by the user, the program calculates the appropriate zone(s) based on the input data provided. The output then provides the UTM zone numbers found (if more than one), the geographic region covered within each zone, and the percentage of data points found in each zone. The user must then decide which of these UTM zones contains the major or most important portion of data values, so that the zone number can be supplied in creating the GRASS location to hold the imported data and can be provided to the importing program (v.in.tiger). Zone edges will be extended (reasonably) to include data values lying outside the chosen zone. If desired, m.tiger.region can be re-run, supplying the chosen zone number, in order to evaluate the region edges of the input data set (with the extended zone).
The RIM Users manual.
The RIM reference manual.
Source code for v.db.rim is located under $GISBASE/../src.garden/grass.rim/ v.db.rim
Source code for v.in.tiger is located under $GISBASE/../src.garden/grass.tiger/v.in.tiger
Source code for m.tiger.region is located under $GISBASE/../src.garden/grass.tiger/m.tiger.region
Gen.Maps,
Gen.tractmap,
g.region
v.db.rim
v.in.tiger
r.info
.sh