Coyote Graphics Map Projection Routines

Date: Fri Nov 29 13:44:27 2013

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result = cgFindMapBoundary(filename [, boundary] [, /USE_LATLON] [, /UTM_SOUTH] [, XRANGE=float] [, YRANGE=float])

Utility routine to find the map projection grid boundary from a file, if it is possible to do so. Currently works with GeoTIFF files, CF 1.4 compliant netCDF files, and GPD files created with the GPD_Viewer software from the Catatlyst Library.

Return value

The return value is either a 1, indicating a boundary can be found, or a 0 indicating that the boundary could not be found.


filename in required type=string

The name of a filename to open to see if a projected map grid boundary can be found.

boundary out optional type=float

The boundary of the image in projected meter space, in the form [x0,y0,x1,y1].


USE_LATLON in optional type=boolean default=0

If the filename is a netCDF file, set this keyword to force the boundary to be determined by reading the include latitude/longitude arrays.

UTM_SOUTH in optional type=boolean default=0

Set this keyword to add 10e6 to each of the Y values. This is sometimes necessary with LandSat images in the Southern hemisphere, where the Y values are given in negative values to indicate southern UTM zones.

XRANGE out optional type=float

A two element vector: boundary[[0,2]]

YRANGE out optional type=float

A two element vector: boundary[[1,3]]

Author information



David W. Fanning 1645 Sheely Drive Fort Collins, CO 80526 USA Phone: 970-221-0438 E-mail: Coyote's Guide to IDL Programming:


Copyright (c) 2012, Fanning Software Consulting, Inc.


Written by: David W. Fanning, 23 February 2010.:

Added XRANGE and YRANGE keywords. 25 February 2010. DWF Added USE_LATLON keyword for finding boundary of netCDF files containing latitude and longitude arrays. 6 April 2010. DWF. Added UTM_SOUTH keyword to handle Landsat dat in UTM projections in GeoTiff files that have to have 10e6 added to Y values to make them work in IDL. 14 Aug 2012. DWF. Renamed cgFindMapBoundary from FindMapBoundary. 21 Aug 2012. DWF. Changed reference to NCDF_Coord to cgNCDFMap. 28 Oct 2012. DWF.

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Modification date: Sun Oct 28 07:15:48 2012
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