setenv GRIDDESC   <path name>     # if grids are referenced by name

    <and respond to the prompts>
Supersedes utmtool, which has been removed for I/O API-3.2 and later.


The PROJTOOL program provides coordinate conversion back and forth among LAT-LON, Lambert Conformal, UTM, Polar Stereographic, General Transverse Mercator, Equatorial Mercator, and Albers Conic Equal Area coordinate systems. Longitudes are specified in signed degrees (so that for the US, longitudes are negative); coordinate system "UAM/EPS" means the thing with the kilometer units instead of the UTM standard units, which are meters.

Inputs are 8-byte REAL (double precision), matching the double precision used internally by GCTP. For high precision calculations, uses the I/O API SETSPHERE and SPHEREDAT package to allow the user to customize the geodetic spheroid to be used for such high precision computations.

PROJTOOL also provides grid-corner calculations, assuming either a UTM-based or a Lambert-based grid, as appropriate (to get UTM or Lambert corners of a LAT-LON based grid, work one corner at a time using the coordinate conversion facilities).

NOTE: according to the standard, UTM coordinates should be specified in meters instead of the UAM/EPS bastardized system which claims to be UTM but in fact uses kilometers; the latter is a distinct (partially-supported) system, also.


The program is a character-based application (runs in, e.g., an xterm) rather than being a GUI X application. It will repeatedly prompt you for operation to be performed, from a menu that offers the following choices, for specification of (input or output) coordinate transformation, coordinate-to-coordinate conversion, and grid-corner determination. Note that for Lambert, Polar Stereographic, Transverse Mercator, and Equatorial Mercator projections, you must specify it before using it as an input or output coordinate system.

The menu is given below. Note that it will show only choices currently available — one must define the input and output projections before doing coordinate transforms between them.

  1. Quit the program
  2. Set up input map projection by name
  3. Set up output map projection by name
  4. Set up input grid & projection by name
  5. Set up output grid & projection by name
  6. Set up input map projection by angles (etc.)
  7. Set up output map projection by angles (etc.)
  8. Define an input grid w.r.t. the input map projection
  9. Convert from input X-Y to output X-Y
  10. Get output-projection grid corners for input grid, e.g., for Lat-Lon corners, set the output projection to Lat-Lon and choose this action.
  11. Get output-projection grid corner-cell centers for the input grid,
  12. Define an output grid w.r.t. the output map projection
  13. Get output-grid <C,R> for input-coord <X,Y>

See Also

M3TOOLS program LATLON to construct one-layer GRIDDED and BOUNDARY files with variables LAT and LON

Earlier (obsolete) M3TOOLS coordinate-transform program UTMTOOL

EDSS/Models-3 I/O API horizontal coordinate and grid conventions

EDSS/Models-3 I/O API grid and coordinate manipulation routines

US Geological Survey General Coordinate Transformation Package (GCTP)

I/O API 3.2 MODULE MODGCTP for GCTP related routines and INTERFACEs

I/O API single precision coordinate manipulation routines LAMBERT, POLSTE, TRMERC, EQMERC, ALBERS,, etc.

I/O API Geodetic spheroid manipulation routine SETSPHERE

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