GMT (Generic Mapping Tools)

The GMT data processing and display software package is a collection of public-domain Unix tools that allows you to manipulate x,y and x,y,z data sets (filtering, trend fitting, gridding, projecting, etc.) and produce PostScript illustrations ranging from simple x-y plots, via contour maps, to artificially illuminated surfaces and 3-d perspective views in black/white or 24bit color.

Linear, log10, and power scaling is supported in additon to 20 common map projections. The processing and display routines within GMT are completely general and will handle any (x,y) or (x,y,z) data as input. The package also includes a database of coastlines, lakes and rivers, and political boundaries. Another useful feature is a Fortran or C-callable PostScript plotting library that can be used to access many of the output capabilities of GMT from within your own programs.

A typical GMT session will involve a series of commands, put together in a UNIX shell script. Each tool has a large number of command line options, which determine such things as what map projection is being used, the area of interest and the weight and colour of the pen used for drawing lines and annotation.

Using GMT on the IT AIX system

To get started with GMT on the IT AIX system, type:

  . use gmt

  man gmt

Full GMT documentation is available locally at http://www.acs.ucalgary.ca/~appinst/doc/gmt/gmt_services.html

Examples

Some locally-developed examples are shown below. Other examples are available at the GMT home page at http://imina.soest.hawaii.edu/gmt/ .

• Map of North America

  Click here to see the script that was used to produce the following map:

  

  Larger image (~12K,728x510 pixels )

• Annotated map illustrating use of GMT utilities psxy and pstext.

  Click here to see the script that was used to produce the following map:

  

  Larger image (~12K,728x510 pixels )

• Annotated map of earthquakes in Canada

  This map was prepared for Dr. Patrick Wu from Geology and Geophysics. It illustrates some more advanced features of psxy and pstext, such as dashed lines, multi-segment files, use of a map projection and absolute positioning of elements on the page. Click here to see the script that was used to produce the earthquakes map:

  

  Larger image (~24K,608x514 pixels )

• CT-scan image with coloured histogram legend

  This example illustrates output from calls to the PostScript-based plotting library, pslib, that is shipped with GMT. This library may be called from either Fortran or C programs.

  In the present example, the library calls were used to lay the images out on the page, to construct the histogram from a series of rectangles and to add annotate the image with PostScript text. The purpose was to obtain high-quality printed output. The bit-mapped represenation of the text shown here does not reflect the quality of the printed output.

  

  Larger image (~160K, 660x1273 pixels)

• Other mapping software and data

  There are several GIS, remote sensing and other software packages on the IT AIX system that can be used for producing maps from data.

  • GIS software
  • U of C Map and Airphoto Library

• 1996-09-13 - Added GMT description at beginning
• 1996-09-13 - Added references to AIX software library and Map library.
• 1997-02-03 - Added instructions for accessing GMT on UCS AIX.
• 1998-04-14 - Updated link to U of C map library and GMT home page.
• 2003-09-11 - Removed NCAR Graphics reference.