Bug report #20966

algorithm create grid: reference point problem for calculating Y coordinates

Added by Alain FERRATON over 5 years ago. Updated over 5 years ago.

Status:Closed
Priority:Normal
Assignee:-
Category:Processing/QGIS
Affected QGIS version:3.4.3 Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:28785

Description

The reference point for calculating the other points seems to be the top left point of the grid.
It is expected that the bottom left point will be the reference point.

This is a problem if the maximum Y coordinate is not of the form Ymin + n*deltaY with n integer.

The MMQGIS create grid function gives the expected results, even in this case.

see attached illustration

grille__param_nok.png (22.1 KB) Alain FERRATON, 2019-01-10 11:36 AM

résultat.png (30.2 KB) Alain FERRATON, 2019-01-10 11:36 AM

grille__param_ok.png (18.7 KB) Alain FERRATON, 2019-01-10 11:36 AM

Associated revisions

Revision e3516ab1
Added by Victor Olaya over 5 years ago

[processing] fixed qgis algorithms help file

fixes #20966

History

#1 Updated by Giovanni Manghi over 5 years ago

  • Status changed from Open to Feedback
  • Category changed from Processing/GUI to Processing/QGIS

Does it works as expected on 2.18?

#2 Updated by Alain FERRATON over 5 years ago

  • Status changed from Feedback to Open

Same problem under QGIS 2.18 and QGIS 2.16

#3 Updated by Victor Olaya over 5 years ago

  • % Done changed from 0 to 100
  • Status changed from Open to Closed

#4 Updated by Victor Olaya over 5 years ago

This doesnt seem to be a bug. The code clearly uses that reference point, and the corresponding tests do so. I have updated the documentation to make it clear that the top left point is the reference point for this algorithm

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