Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
10,519
questions with no upvoted or accepted answers
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answers
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views
Processing post-execution script hook to clear scratch layers?
I've been cobbling together some Processing scripts for QGIS 2.18 (I'm not a fan of QGIS 3 scripts), and I keep running into one particular problem: my script creates a lot of scratch layers and they ...
- 575
11
votes
2
answers
2k
views
QGIS GRASS Processing Not Working on MacOS?
Recently upgraded to QGIS3 (3.0.2) for MacOS (High Sierra) and encountered GRASS (7.2.2) issues. Tried adding a custom variable and now when running GRASS algorithms (e.g. r.reclass) I get the ...
- 111
10
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answers
703
views
How to use a Spilhaus/ESRI:54099 projection in QGIS
I am trying to make a map using a Spilhaus projection, similar to the one implemented by Esri here. QGIS has ESRI:54099 WGS_1984_Spilhaus_Ocean_Map_in_Square in its list of available projections, ...
- 405
10
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359
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Performance-limits of QGIS expressions
I use quite often QGIS expressions and I am wondering how performant they are compared with other possibilities. In many cases, the same problem can be resolved using different approaches like using ...
- 73k
10
votes
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answers
1k
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Grouped "labels" for QGIS 3.0 Point Cluster styling?
I'm trying to make a cluster visualization of a vector point layer about trees with a few requirements:
The clusters need to change depending on zoom level (solved)
The clusters need to indicate how ...
- 133
9
votes
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answers
123
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Does QGIS use data source-specific operations?
This may be a very basic question, but I couldn't find an appropriate answer.
Does QGIS use data source specific operations where available and appropriate? For example, when using the Join attributes ...
- 376
9
votes
1
answer
1k
views
GRASS v.clean tool in QGIS gives empty output
I am trying to run v.clean in QGIS 3.10.7. I have a 2D LineString dataset saved in GPKG format and I want to run v.clean to clean up some messy topology.
But whenever I run it, I get the same result - ...
- 3,598
9
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answers
1k
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Nearest neighbour joins for two geodataframes using KDtree from scipy/sklearn
I have a number of large geodataframes and I want to automate the implementation of a Nearest Neighbour function using a KDtree for more efficient processing. The process I want to achieve here is to ...
- 91
9
votes
0
answers
869
views
Change from LineString to MultiLineString when saving layer edits in QGIS
In QGIS, when a user creates a new single part line in an open editing session for a “Multi-Line” SpatiaLite dataset, the QGIS data type is initially a “LineString”. But, when the user commits the ...
- 997
8
votes
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answers
149
views
Exporting Geopackage converts milliseconds of QDateTime to zero
I use this solution to display actual QDateTime value with milliseconds in a temporary memory layer. And I use another solution to export as CSV the value including the millisecond value.
But then, I ...
- 77.3k
8
votes
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answers
461
views
QGIS contextual menu overriding
I would like to override the default contextual menu in QGIS 3 in the ToC.
I've created a class that inherit from QgsLayerTreeViewMenuProvider.
from qgis.gui import QgsLayerTreeViewMenuProvider
from ...
- 523
8
votes
0
answers
1k
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Add private plugin repository to QGIS 3.4
I want to add a repository to my QGIS 3.4 which is on a private server. The repository contains all files needed (plugin.xml and metadata.txt for example) and has the structure as described here:
Is ...
- 555
8
votes
0
answers
2k
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Question marks ("?") in QGIS layer panel when using SVG markers defined with "Data defined override"
When using SVG marker symbols and set the path to SVG file via Data defined override the SVGs display well in the map canvas, but not in the layers panel (applies for QGIS 2.x and 3.x).
SVG marker ...
- 14.6k
8
votes
0
answers
13k
views
Creating in-line variable in field calculator of QGIS
I create new field based on other fields. For example; if "Field_A" is smaller than "Field_B", the value of the new field is 'A', otherwise it is 'B'. So I want to create a new ...
- 77.3k
8
votes
0
answers
214
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Issues with atlas generator and labelling across maps/images
I have a lot of layers in my project and I am trying to use the atlas generator in the print composer to create a tiled map. Some of the layers have labels which have different configurations with ...
- 4,480