[GRASS-user] v.out.ascii output is different than the original ascii raster

[Maciek Sieczka]

Hi,

I've got double floating point Grass ASCII raster (dem.asc, attached).

I do:

	r.in.ascii -d input=dem.asc output=dem

	r.out.ascii input=dem output=dem2.asc

and compare dem.asc vs dem2.asc, to notice that all values in dem2.asc
(attached) are slightly different (sometimes lower, sometimes higher).

Eg. the first floating point value in dem.asc is:

	104.999999999197

while in dem2.asc it's:

	104.9999999991970014

The 2nd one in dem.asc:

	104.999999999756

and the 2nd in dem2.asc:

	104.9999999997559996

And so on, all of them. Why aren't they equal?

I'm using r.out.ascii and r.in.ascii in a script to interface with
external program and I would expect Grass to preserve exact values.

A bug?

Maciek


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