How to get the HAniS "coordinates" parameter values from McIDAS

Page updated: May, 2022

The HAniS "coordiantes" parameter defines map projection information. If you are using Polar Stereographic projections on images that were obtained from McIDAS (probably using the IMGREMAP command), then the projection data can be obtained from the values specified in the IMGREMAP command.

HAnis defines the "coordinates" parameter for a Polar Stereographic projection this way:

coordinates = PS, refLat, refLon, origLat, origLon, EquatorRadius, Spacing, eccentricity, northPoleFlag, xOrig, yOrig
This form specifies a Polar Stereographic Ellipsoid coordinate system.

refLat = reference latitude (degrees, often 60)
refLon = reference longitude (degrees, east positive)
origLat = latitude of the origin (degrees, see yOrig)
origLon = lontitude of the origin (degrees, see xOrig)
EquatorRadius = equatorial radius
Eccentricity = eccentricity
Spacing = distance between grid (image) points (same units as radius)
northPoleFlag = 1 (north pole) or 0 (south pole)
xOrig = x coordinate of origin (0 for upper left corner)
yOrig = y coordinate of origin (0 for upper left corner)

Here is an example, derived from McIDAS:

The an example McIDAS command to remap an image: IMGREMAP SOU/IMG.1 DES/IMG.1 LAT= 45.50 85.50 PRO=PS RES=3.5 SIZE=970 1100 Would then need this in HAniS: coordinates= PS, 60.00, -85.50, 45.50, -85.50, 6378137.0, 0.081819, 3500.0, 1, 550, 485 where: # refLat => standard latitude (60 unless otherwise specifed in IMGREMAP) # refLon => longitude * -1 (use image center longitude unless specified in IMGREMAP - east positive) # origLat => latitude (center longitude specified in IMGREMAP) # origLon => longitude * -1 (image center longitude specified in IMGREMAP - east positive) # EquatorRadius => radius of Earth (usually in meters, normally 6378137.0) # Eccentricity => as a floating point number...e.g., 0.081819 -- derived from McIDAS value of 81819) # Spacing => image resolution (floating point value with same units as radius, as specified in IMGREMAP...also found in word 68 of AREA directory - LWU LIST AREA0001 # northPoleFlag => pole flag == 1 for North Pole # xOrig => image element at center of image (.5 * number of elements, as specified with SIZE= in IMGREMAP) # yOrig => image line at center of image (.5 * number of lines, as specified with SIZE= in IMGREMAP)

Thanks to Rick Kohrs at SSEC for his help with this.

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