[GRASS-dev] Error reading null row 8 for <MASK>

Paulo van Breugel p.vanbreugel at gmail.com
Wed May 6 00:20:58 PDT 2015



On 04-05-15 20:36, Markus Neteler wrote:
> On Mon, May 4, 2015 at 8:05 PM, Alba German <albagerman at gmail.com> wrote:
>> Hello!
>> I am running a loop with several r.mapcalc. I am using GRASS 7.1. The
>> function stops with an error:
>>
>> ERROR: Error reading null row 8 for <MASK>
>>
>> I've noticed that Paulo van Breugel, had the same error but I didn't see the
>> solution to it.

You are referring to this email: 
http://lists.osgeo.org/pipermail/grass-dev/2014-September/070584.html. 
Can't recall how / if I solved this, but I haven't encountered it 
recently. The difficult part of it was that it appeared to happen at 
random, i.e., the same function and same data would run without problem 
in one instance and end with the above-mentioned error in another instance.

>> Obviously it has something to do with the raster called
>> MASK, created with r.mask before running the loop of multiple r.mapcalc.
>> The code itself has no problem and is very simple and works just fine with
>> the same list of images, but without running r.mask first.
> Hi Alba,
>
> could you post that part of the code e.g. here
> http://pastebin.com/
>
> ? It sounds like a race condition...
>
> Markus
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