NAME

m.tiger.region - Finds geographic region information for U.S. Census Bureau TIGER input data.
(GRASS Data Import/Processing Program)

SYNOPSIS

m.tiger.region
m.tiger.region help
m.tiger.region infile=name [zone=value] [spheroid=name]

DESCRIPTION

m.tiger.region is a program designed to evaluate a file of raw type 1 Census (TIGER) data and determine the geographic region covered by that input file. Output is sent to standard out, and gives the east, west, north, and south boundaries for the given input data file.

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.

OPTIONS

Parameters:

infile=name
Input file name in which raw TIGER data (type 1) are stored.
zone=value
Universal Transverse Mercator (UTM) zone for this county.
Options: -60 - 60
Default: 0
spheroid=name
Name of spheroid to be used.
Default: clark66

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.

EXAMPLES

If the user typed simply:

m.tiger.region infile=inputfilename

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)

NOTES

This command must be compiled separately. It will not automatically be included in the compile of the main GRASS code. Although m.tiger.region does not need a FORTRAN compiler, it is used to support other TIGER data functions (like v.db.rim , v.in.tiger, and rim) which do require access to a FORTRAN compiler.

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).

FILES

Source code for RIM is located under $GISBASE/../src.related/rim

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

SEE ALSO

Gen.Maps, Gen.tractmap,
g.region
v.db.rim
v.in.tiger
r.info .sh

AUTHOR

Marjorie Larson, U.S. Army Construction Engineering Research Laboratory

Last changed: $Date$