[GRASSLIST:3629] more r.mapcalc troubles

[Maciek Sieczka]

Hello Everyone!

Thanks for the support so far! Here is one more strange thing in r.mapcalc I
encountered during my low-level computing :).

I'm using Grass 5.03 installed from the binaries from the Grass www.

I made a following raster for my vignetting correction purposes:

    r.mapcalc 'kor_lx = ( 1218.01 / ( sqrt(  (double(x()) - 941.0) ^2.0 +
    (double(y()) - 928.0)^2.0) ^2.0 + 1218.01^2.0) ) ^4.0'

the value range for 'kor_lx' file is (read from the color file in the 'colr'
folder):

    0.00000000000002026206628416476 - 0.000000000000454355718931865126

I checked if r.mapcalc hadles the 'kor_lx''s values properly by doing:

    r.mapcalc 'copy=kor_lx'

the data range in the 'colr' file for 'copy' was DIFFERENT (the min value is
higher than in 'kor_lx'):

    0.000000000000028123670807620238 - 0.000000000000454355718931865126

the difference is:

    0.000000000000028123670807620238 - 0.00000000000002026206628416476
    = 0.000000000000007861604523455478

how come?

The difference beetween 'kor_lx' and the 'copy' is very well visible on the
attached window dump. It's a  "copy" partly drawn over the "kor_lx" (caught
in the 1/4 of drawing on Grass monitor - see the upper 1/4 of the picture).

Maciek Sieczka
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