# Blockmean pre-processing data

**URL:** <https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489>\
**Category:** Q&A\
**Created:** [March 24, 2021, 10:49am UTC](https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489 "2021-03-24T10:49:18Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jrocha](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/jrocha/32/88_2.png) [@jrocha](https://forum.generic-mapping-tools.org/u/jrocha)\
**Post date:** [March 24, 2021, 10:49am UTC](https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489/1 "2021-03-24T10:49:18Z")

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Hello all,  
I’m trying to pre-process a data table with blockmean to use after with surface and grdview but it seems no points are found inside the specified region and so no output is produced.  
Any help on this?  
Thanks.  
João Rocha

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**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://forum.generic-mapping-tools.org/u/Andreas)\
**Post date:** [March 24, 2021, 11:35am UTC](https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489/2 "2021-03-24T11:35:33Z")

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Can you provide the command that you use? And data? It’s impossible to help without getting more information.

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<div class="post-metadata">

**Author:** ![jrocha](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/jrocha/32/88_2.png) [@jrocha](https://forum.generic-mapping-tools.org/u/jrocha)\
**Post date:** [March 24, 2021, 12:35pm UTC](https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489/3 "2021-03-24T12:35:59Z")

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Hi Andreas,  
Thanks for your reply. Meanwhile i’ve been able to resolve the problem. I was using coordinates but without -: and so GMT could not plot the points.  
Thanks a lot anyway.  
Cheers  
João Rocha

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**Author:** ![jrocha](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/jrocha/32/88_2.png) [@jrocha](https://forum.generic-mapping-tools.org/u/jrocha)\
**Post date:** [March 24, 2021, 12:41pm UTC](https://forum.generic-mapping-tools.org/t/blockmean-pre-processing-data/1489/4 "2021-03-24T12:41:58Z")

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…by the way, the output image is somehow filled with lines, is there a way i can clean this off?[surface2.pdf](https://forum.generic-mapping-tools.org/uploads/short-url/lZdB6RkYJAH3sG8VQZ8mQ9ehhue.pdf) (163.3 KB)  
Thanks once more.  
Cheers