Hi,
dealing with large amount of maps, some of them process to NULL on all pixels.
when accessing fp_range in cell_misc, the file is empty, thus returning such an error:
WARNING: Unable to read fp range file for NULL_map_test@PERMANENT
While I understand this is undefined because of all pixels being NULL,
would it be possible to have a more interesting output?
This could help in screening NULL maps too…
Thank you,
Yann
–
Yann Chemin
Researcher@IWMI
Skype/FB: yann.chemin
Yann Chemin wrote:
dealing with large amount of maps, some of them process to NULL on all
pixels.
when accessing fp_range in cell_misc, the file is empty, thus returning
such an error:WARNING: Unable to read fp range file for <NULL_map_test@PERMANENT>
While I understand this is undefined because of all pixels being NULL,
would it be possible to have a more interesting output?
lib/raster/range.c is inconsistent in this regard. When writing an FP
range, it writes an empty file if the range is null:
/* if range hasn't been updated, write empty file meaning Nulls */
When reading an empty f_range file, it generates the above warning
(the FPRange structure is initialised with min and max both null).
It would be a simple matter to change the warning (e.g. "range is
null") or remove it. A warning might be useful, as I can imagine
modules failing in interesting ways if an input map is all-null.
--
Glynn Clements <glynn@gclements.plus.com>
On 6 March 2013 23:35, Glynn Clements <glynn@gclements.plus.com> wrote:
Yann Chemin wrote:
> dealing with large amount of maps, some of them process to NULL on all
> pixels.
> when accessing fp_range in cell_misc, the file is empty, thus returning
> such an error:
>
> WARNING: Unable to read fp range file for <NULL_map_test@PERMANENT>
>
> While I understand this is undefined because of all pixels being NULL,
> would it be possible to have a more interesting output?lib/raster/range.c is inconsistent in this regard. When writing an FP
range, it writes an empty file if the range is null:/* if range hasn't been updated, write empty file meaning Nulls */
When reading an empty f_range file, it generates the above warning
(the FPRange structure is initialised with min and max both null).It would be a simple matter to change the warning (e.g. "range is
null") or remove it. A warning might be useful, as I can imagine
modules failing in interesting ways if an input map is all-null.
In the same way as there is a pixel based function to assess a NULL pixel
value,
it would be very interesting to have a function to test an all NULL raster
map status.
Time series analysis would be the first to benefit.
--
Glynn Clements <glynn@gclements.plus.com>
--
Yann Chemin
Researcher@IWMI
Skype/FB: yann.chemin