[GRASS-user] i.segment.stats memory usage error

[Moritz Lennert]

On 04/11/16 14:29, Markus Metz wrote:
> On Wed, Nov 2, 2016 at 5:15 PM, Markus Metz
> <markus.metz.giswork at gmail.com> wrote:
>> On Wed, Nov 2, 2016 at 3:47 PM, Moritz Lennert
>> <mlennert at club.worldonline.be> wrote:
>>> On 02/11/16 11:05, James Duffy wrote:
>>>>
>>>> I can't register with osgeo to submit a bug as no-one has replied with a
>>>> 'mantra' for me to do so... what a convoluted bug reporting system!
>>>>
>>>> And in your opinion Moritz, does it look like my workflow will not be
>>>> possible unless I find a 64bit machine with a decent amount of RAM?
>>>
>>>
>>> I'm not sure about the necessity of 64bit, but more RAM probably.
>>>
>>> IIUC, all the stats of all the zones are put into memory during the run of
>>> the module. Maybe a file-based store of the information might be possible
>>> which would avoid this memory usage, but I'm not sure.
>>>
>>> @MarkusM: could you have a look at this ? See
>>> https://lists.osgeo.org/pipermail/grass-user/2016-October/075493.html for
>>> the beginning of the thread. In short: James seems to be hitting memory
>>> limits of r.univar and I'm wondering out loud whether there is something
>>> that could be done about this...
>>
>> As Anna wrote, the -e flag increases memory consumption of r.univar
>> considerably. A file based approach for extended stats of r.univar is
>> difficult because the number of values per segment is initially
>> unknown to r.univar, thus the amount of disk space needed for extended
>> stats for each segment is unknown.
>>
>> I would rather use r.univar for standard stats and r.stats.quantile
>> for extended stats.
>
> There were some bugs in r.stats.quantile, fixed in r69770-2 in all G7 branches.

Great, thanks !

>
> About the limit to MAX_CATS categories in the base map (ticket #3198),
> there is not really a reason for it. I guess it is meant to protect
> against out-of-memory errors.

Does this mean we can just take out the lines referencing it ?

Moritz