Re: r.stream.extract error

Micha Silver <[email protected]>
Newsgroups gmane.comp.gis.grass.user
Message-ID <[email protected]>
Hello

On 11/16/2017 11:51 PM, Giuseppe
Amatulli wrote:

Hi Markus M.

I was testing the r.stream.extract for 2 tiff

1) 80040 x 72870 = 5,832,514,800 i got the stream results -
no error

2) 80490 x 142690 = 11,485,118,100 i got the following
error

A* Search...

0..2../var/spool/slurmd/job6514787/slurm_script: line 80:
28925 Bus error r.stream.extract elevation=elv
accumulation=upa threshold=0.5 depression=dep direction=dir
stream_raster=stream memory=45000 --o --verbose

I think it was already mentioned in this thread: the threshold=0.5
is certainly wrong. The threshold value is *number of pixels* for
minimum basin size. Usually it would be in the thousands. With your
region size of 11 billion you probably want a threshold of tens of
thousands.

Do you think that is something with the slurm ram
limitation or is something with the r.extract.stream?

If the the stream output have a number of stream segments
larger than 2,147,483,647 what is happen?

Do I get an error or all the value larger than
2,147,483,647 are just rounded to 2,147,483,647 ?

Moreover, if use the stream obtain from option 1) and I use
the stream as input for the r.stream.basins

I got the following error

reading raster map <stream>...

0..3..6..9..12..15..18..21..24..27..30..33..36..39..42..45../var/spool/slurmd/job6514788/slurm_script:
line 82: 17687 Bus error
/gpfs/home/fas/sbsc/ga254/.grass7/addons/bin/r.stream.basins
-l stream_rast=stream direction=dir

is this something that need to be fixed in r.stream.basins,
or should i think that is due to other problems

Thank you

Giuseppe

On 10 November 2017 at 11:21, Markus
Neteler <[email protected] >
wrote:

On Wed, Nov 1, 2017 at 10:12 PM, Markus Metz

<[email protected] >
wrote:

> On Wed, Nov 1, 2017 at 7:15 PM, Giuseppe Amatulli

> <[email protected] >
wrote:

>>

>> Thanks Markus!!

>> I will test and I will let you know how it works.

>

> Your feedback is very helpful!

>>

>> I have few more questions

>> 1) now how much is the upper limit matrix cell
number that

>> r.stream.extract can handle?

>

> About 1.15e+18 cells.

>

> Another limitation is the number of detected stream
segments. This must not

> be larger than 2,147,483,647 streams,

...

(Added as a note to

https://grasswiki.osgeo.org/wiki/GRASS_GIS_Performance#Some_benchmarks

)

best,

markusN

--

Giuseppe Amatulli,
Ph.D.

Research scientist at

Yale School of
Forestry &
Environmental
Studies

Yale
Center for Research
Computing

Center for
Science and Social
Science Information

New Haven, 06511

Teaching: http://spatial-ecology.net

Work: https://environment.yale.edu/profile/giuseppe-amatulli/

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--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918

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