[GRASS5] Severe internal bugs in raster format

[Bruce_Byars at baylor.edu]

I heard a rumor yesterday that esri will be changing their
e00 format slightly in the near future.  As soon as I have
info I'll pass it along.

Bruce

Markus Neteler wrote:

> Dear developers,
>
> sorry for bad news: but it seems there is a lot
> of confusion in raster format read/write in several
> modules:
>
> Example:
>  d.rast a_raster_map
>  d.rast.zoom # we want to look at some pixels only
>  d.rast.num  # show cell values
>  d.what.rast # query with mouse: result is different
>  r.out.ascii # result is different as well
>
> (from A. Lobo:)
> r.stats: some inconsistent results comparing to r.average
>  *First, I compute the per-class averages:
>      r.average base=medv cover=test out=borra.me
>  *Second, I check the result for, i.e., class 23:
>      d.what.rast map=medv,borra.me
>      2676500(E) 4409500(N)
>            medv in user1  (23)S_SUPRAMEDITERRANEAN_ZONE
>            borra.me in user1, quant   (111)
>            borra.me in user1, actual  (110.794075)
>  *Third, I compute the statistics for each class, but the results are not
>   the same as given by d.what.rast. For example, for class 23:
>      r.stats -c in=medv,borra.me
>      r.stats:  100%
>        ...
>        23 110.299171-110.744906 6082
>        ...
>  *While d.what.rast was giving 110.794075.
>
> We should check this quickly, otherwise we cannot trust any result.
> I guess the problem is due to ".5" (half raster cell) addition
> for query any some potential mixture of
>   - save values at cell center
>   - save values at cell corner (which is wrong as far as I know but correct
>                                 for ESRI).
>
> Another bug: r.in.arc reads in ARC/INFO grid files reversed.
> ESRI saves from lower left to upper right, GRASS from
> upper left to lower right. The module does not (yet) take
> care of this. I would be able to fix in GRASS 4.x but in GRASS 5
> the row number cannot be specified any more (G_put_raster_c_row()).
> So we have to flip the input file or something else... How to do this?
>
> Your help is appreciated!
> Hope to have better news soon,
>
>  Markus
>
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