[GRASS-user] segment_format error with r.watershed

[Markus Neteler]

Wes,

IMHO your problem indicates that you are exceeding the 32bit
limits for file size (I may be wrong but Total Cells: -1831011296
may indicate that).

GRASS >= 6.0 includes experimental support for reading and writing large files
(> 2GB) if it is possible in your operating system. If you compile with
  configure [...] --enable-largefile
you should be able to have raster maps which are larger than 2GB.

Note that the support currently only applies to the core raster I/O code.
Individual programs may or may not work with large files - please report.

Markus

On Jan 29, 2008 2:26 PM, Wes Kent <wkent at medinaco.org> wrote:
> Greetings all,
>
> I am trying to run r.watershed on a county-wide LIDAR data layer.
> However, r.watershed returned a segment_format error during Section 1 of
> the analysis.  Here is the error output:
>
> SECTION 1 beginning: Initiating Variables. 5 sections total.
>
> segment_format(fd,1,-1831011296,1,25,20): illegal value(s)
>
> seg_open(): illegal configuration parameter(s)
>
>
> Also, for reference, here is the information for the elevation input map
> being used:
>
>
> Type of Map:  raster               Number of Categories: 255
>  |   Data Type:
> FCELL
>  |   Rows:
> 44000
>  |   Columns:
> 55999
>  |   Total Cells:
> -1831011296
>  |        Projection: State
> Plane
>  |            N: 589970.67755842    S: 479971.19725012   Res:
> 2.49998819
>  |            E: 2226464.7485208    W: 2086468.7440966   Res:
> 2.49997329
>  |   Range of data:    min = 764.770020  max =
> 1324.199951
>  |
>
>  |   Data
> Description:
>  |    generated by r.patch
>
>
> The raster layer consists of about 530 separate grids that were patched
> together in stages using r.patch.  The resolution of the layer is 2.50 feet.
>
> I am not able to determine what would have caused the error.  Are there
> too many rows/columns, or is the negative value for the "Total Cells"
> causing a problem?  Perhaps I used the wrong approach in patching the
> individual grids together?
>
> If any additional information is needed, let me know, and I will do my
> best to provide it.  Many thanks for any and all assistance.
>
>
> ~Wes