New answers tagged qgis
0
votes
Using variable input in select by expression does not work in QGIS Modeler
The issue is actually simpler, when using a variable and ones that depend on previous processes, switch from "Value" to "Pre-calculated Value" in the expression dropdown then wrap ...
- 101
1
vote
Problem by rasterizing in QGIS 3.28.4
Your screenshot shows that your created a raster 1 pixel widht, 1 pixel height. Adapt resolution and units to get proper results.
- 55.5k
1
vote
Fill nodata holes in discrete integer raster with majority value of adjacent pixels QGIS
Past self, you can use the Grass algorithm r.neighbors in QGIS to do this.
First create a mask layer that is the inverse of the layer you want to fill.
This means that all the NoData cells you want to ...
- 2,119
2
votes
Set the background of a label such that it fits to a wrapped line in QGIS
If you know for sure that all your labels will have consistent length, you can make a custom background as an image file.
Use GIMP or another software to create your background
Choose Marker Symbol ...
- 12.3k
0
votes
Set the background of a label such that it fits to a wrapped line in QGIS
Coming close to what you want: draw large enough text buffers:
- 55.5k
0
votes
Use child's last values for new child feature
Use aggregate fuction array_agg() to collect all vitality-values, grouped by tree_id, ordered by date. Exclude the current feature (the one you want to update) with optional filter condition. This is ...
- 55.5k
0
votes
Set a relative path for PDF linking to shapefile
Using QGIS expression with function file_path() and variable @layer, you get the path of the current layer: file_path (@layer).
Concatenate this with the filename to get what you want, using function ...
- 55.5k
2
votes
Join attributes by location won't sum values in QGIS
You would have to use the tool Join attributes by location (summary).
Feel free to look at this tutorial
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0
votes
How do I use the GDAL raster calculator in QGIS to calculate P using conditional equations based on pixel values in another layer?
I've done a lot of raster processing (mostly biophysical data like yourself) and in my experience, map algebra more complicated than result = map1 + map2 is very cumbersome in both QGIS and Arc, and ...
- 411
1
vote
Which version of Python is installed in the OSGeo4W shell?
or other way from within the python console:
import sys
print('{}.{}'.format(sys.version_info.major,sys.version_info.minor))
- 8,583
1
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Which version of Python is installed in the OSGeo4W shell?
Open an OSGEO4W command shell and type python --version or you can check in the installer which will show you the version that is currently and about to be installed.
- 78.2k
0
votes
In Google Earth Engine, can I export a layer with visual parameters added to a GeoTIFF?
Define pixel size while exporting e.g.
Export.image.toDrive({
image: image.visualize(visParams),
scale: 30,
...
});
- 1
0
votes
Map tips showing only path instead of pictures in QGIS?
You can experiment with the maptips to see how the string you are using parses out before you put it in the image tag. You can also construct the paths from variables like [% @project_folder %] to ...
- 1,579
0
votes
Show images related to features in QGIS?
It works with "Forms" if you have an attribute for your image file. The pathname can be relative.
In QGIS 3.30.0-'s-Hertogenbosch, I have a points layer with a field for a local filename, ...
- 1,579
0
votes
Displaying images as part of multiattribute labels using QGIS
See here a tutorial by Totò Fiandaca: https://www.youtube.com/watch?v=Kckrr6M3t4A
1
vote
Use child's last values for new child feature
If your tree ID is alphanumerically sortable and always increasing, you can simply switch the date field to the tree ID field:
attribute(get_feature('observations', 'tree_id', maximum("tree_id&...
- 9,977
1
vote
Creating callout/balloon labels in QGIS
It is now (QGIS 3) possible using the Balloons label style Callout:
- 61.3k
8
votes
Accepted
Filtering data containing numeric values in QGIS
Use the following expression with function regexp_match(). The Regular Expression \\d finds any digit. Use double backslashes, because in QGIS,
Backslash characters must be double escaped
...
- 55.5k
5
votes
Accepted
Choose all the files of a folder as an input to run a process in the model designer in QGIS
You can execute the model as a batch process.
Press Run model and:
I select all files with 72 in the name in this folder:
The tricky part is to name the outputs.
This expression replaces the input ...
- 61.3k
1
vote
Using NTv2 gridfiles in QGIS >= 3.22.x LTR with proj 9.x
At least for Proj it seems to be possible to use a workaround and update the existing record
UPDATE grid_transformation
set grid_name='kanu_ntv2_mittelfranken.gsb'
WHERE code = 15948;
Now projinfo ...
- 59.2k
3
votes
5
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Converting multiple fields with abbreviations to one field with full names in QGIS
I would recommend using arrays to concatenate your data, especially as you will have some blank/null results which will make typical concatenate (||) not work well and you would need to wrap each ...
- 9,034
0
votes
Accepted
QGIS - Is there a way to filter contents of attribute table in report to features that have a matching attribute field value with report feature?
You can use @atlas_... functions in Report layouts too, as the Group layer apparently works identically to the atlas layer in regular map layouts.
In the 'Filter with' expression dialog, the active ...
- 9,034
1
vote
Could not commit changes to layer X
I was having the same issue of 'could not commit changes' after editing polygons in a shapefile. The only way I found around this was to copy the polygons into a new shape file, which seemed to ...
- 11
1
vote
Gradient colour for lines
As of QGIS 3.30 (released early 2023) and probably a few versions earlier, the interpolated line style seems to allow gradient lines.
The start and end values don't seem to matter for this use case. ...
- 183
1
vote
Using QGIS processing algorithms in C++
QgsApplication::processingRegistry()->addProvider( new QgsNativeAlgorithms( QgsApplication::processingRegistry() ) );
QgsProcessingContext context;
context.setProject(QgsProject::instance());
...
3
votes
Accepted
Importing latitude and longitude data for UK
The coordinates from the archive of weather stations are in WGS 84 project system. Try choosing this for your project (EPSG:4326).
The CEDA web site tells you this if you look further, for example ...
- 100
4
votes
Making points appear on top of lines in QGIS
Simple solution
You can drag the point layer above the line layer in the Layers pane.
More advanced solution
Enable the Layer Order panel via View > Panels > Layer Order
In the Layer Order ...
- 12.3k
6
votes
WFS layer shows blank area, even though there is some information in attribute table
Unfortunately they have configured their service to contain all the geometries as GEOMETRYCOLLECTION datatype, that QGIS does not handle. Test with
https://e-kartta.ouka.fi/TeklaOGCWebOpen/WFS.ashx?...
- 59.2k
4
votes
WFS layer shows blank area, even though there is some information in attribute table
There appears to be an issue with the returned GML whether it be the default GML2, or the GML3 requested by QGIS; that is both of these requests give invalid responses:
https://e-kartta.ouka.fi/...
- 12.7k
0
votes
QuickOSM times out when running a query
Please upgrade to the latest version 2.2.1 of QuickOSM, the list of Overpass server has been updated.
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0
votes
QuickOSM timing out
Please upgrade to the latest version 2.2.1 of QuickOSM, the list of Overpass server has been updated.
- 6,721
6
votes
Accepted
Check Geometries Plugin - attribute value in results
I guess it is the value of the "thinnes" parameter
- 59.2k
0
votes
Why Travelling Salesman Problem plugin is not working in QGIS 3?
You can install it via zip file for QGIS 2 using the answer from:
How do I install a plugin when I have the .zip file for it
- 16.1k
1
vote
Why Travelling Salesman Problem plugin is not working in QGIS 3?
I'd recommend you to stick to ORS Tools plugin, as it supports, amongst other tools and functions, TravellingSalesmanProblem: https://github.com/GIScience/orstools-qgis-plugin
- 414
1
vote
Accepted
Run feature action from canvas for overlapping polygons
You can set the field used to display this value in the list of the identify tool for any layer.
Each feature is described by the name of a field along with its value. This field is the one set in ...
- 2,420
1
vote
Converting multiple fields with abbreviations to one field with full names in QGIS
You might want to use the Field Calculator and tick the option "Create a new field", as in the following picture:
One method could be simply using concat("FISH2","FISH3")...
- 414
0
votes
Using GRASS GIS/QGIS to georeference TIFFs in 3D space, vertically?
Has there been any updates to this issue? Trying to display cross sections from the QGIS Geoscience plug-in in QGIS2Threejs.
- 108
0
votes
How do I eliminate the black border on a georeferenced map layer?
The black borders occur if a NoData value is not assigned to the layer prior to georeferencing.
A NoData value can be added to the layer using Raster>Conversion>"Translate (Convert Format)&...
2
votes
View more than three pictures in the image viewer of QGIS
I have used a different technique to solve the problem (though the full image doesn't appear and I have to scroll to see more). I added a new Tab for each of the photo. It solved part of my problem, ...
2
votes
Accepted
Expression to filter array of features based on relationship to another layer
Instead of IS NULL (because an empty array - i.e. [] - is not NULL), you probably want to filter by length of array.
e.g.
array_length(
relation_aggregate(
relation:= 'Developers',
...
- 9,034
0
votes
PyQGIS - add ArcGIS Feature Service layer to QGIS including a query
While it does not exactly answer the question (because it is not adding the ArcGIS layer directly), the following approach may be useful for some people.
The code
builds up the ArcGIS Feature Server ...
- 643
0
votes
View KML Feed in QGIS
I got this to work by downloading the data rather than using the live view.
At the top left of your screenshot, it says "Found 333 sites" and then there are two buttons. The first downloads ...
- 183
2
votes
Calculate transformation parameters from known common points
Try ogr2ogr https://gdal.org/programs/ogr2ogr.html with -gcp option
-gcp <ungeoref_x> <ungeoref_y> <georef_x> <georef_y>
Add the indicated ground control point. This option ...
- 59.2k
5
votes
Convert Geopackage to Tab file in QGIS?
The issue is caused by the MapInfo TAB format itself and it is a documented behavior of the GDAL Tab driver https://gdal.org/drivers/vector/mitab.html#creation-issues
The TAB File format requires ...
- 59.2k
4
votes
Accepted
Adding parcel number to site when there are many sites in QGIS
I'm not sure I completely understand your question, but [add autoincremental field] in the qgis toolbox may be able to help you. It can take all fields with a specific value and assign numbers to each ...
- 108
6
votes
Adding parcel number to site when there are many sites in QGIS
You can use row_number and partition by site:
--Create a test table
drop table if exists public.test;
create table public.test (id serial, siteid varchar(10));
insert into public.test (siteid)
values ...
- 61.3k
0
votes
How to select features based on layer intersection on QGIS?
Yes we can, see the pic for more details
- 1
3
votes
Accepted
Shapefile saving in project home instead of last used folder in QGIS
Yes, I find this frustrating too. There is a code way to try and fix it which can be run at the python window or added as a macro - see instructions at this answer:
import os
from qgis.core import ...
- 1,677
5
votes
Accepted
Create dashed line with standard length and standard interval
You can create the dash geometry based on your line layer by:
Create points along geometries with a distance of 2.5 m
Buffer them by 0.75 m
Difference with your lines as input and buffers as overlay:
- 61.3k
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