Questions tagged [qgis-3]
for questions specific to the 3.x series of QGIS.
3,726
questions
0
votes
0answers
12 views
Make a Table with fields from different layer groups using PyQGIS [closed]
I have 3 groups, each group consists of 10 layers, layer names are the same in the 3 groups but with different attributes. and I want to make a table of 4 fields:
layer names,
layer lengths of group (...
1
vote
1answer
25 views
QGIS 3.22 Project transformation error
I have installed QGIS 3.22. I got this error when I was trying to open a project.
I downloaded the .tif file.
Then clicked on Install nzgd2kgrid2005.gsb
Then, I got this error.
Any help will be ...
0
votes
1answer
20 views
AttributeError: module 'processing' has no attribute 'runAndLoadResults'
I'm trying to run QGIS standalone app using processing.runAndLoadResults and keep getting this error:
AttributeError: module 'processing' has no attribute 'runAndLoadResults'
I'm working on MacOS i ...
1
vote
0answers
21 views
Correct format for slope and aspect in order to work in QGIS with "r.sun.insoltime" [closed]
I'm using QGIS 3.10 and I should create a raster that shows the hours of sunlight referring to a given day for my province. r.sun.insoltime (Fig. 1, sorry it's in Italian but I traslate) to work asks ...
1
vote
1answer
31 views
Adding new provider to QgsProviderRegistry.instance().providerList() using PyQGIS
I'm trying to get vector layer from arcgisfeatureserver in a standalone app, didn't work, so I checked what providers I got on PyCharm:
['gdal', 'memory', 'mesh_memory', 'ogr', 'vectortile']
While in ...
-1
votes
1answer
36 views
How to keep shared borders in the attributes table of multiple polylines
I have a shapefile of polygons for the countries in Africa. I want to turn them to polylines so I just have the country borders, and then when I look at the border for a given country, I want to have ...
7
votes
1answer
148 views
Labeling numerical data with thousands separator
I am running QGIS 3.18. I have successfully joined a .csv file to a shapefile and am now wanting to show some of the numerical data as labels on the map. Upon joining the .csv to the shapefile, the ...
4
votes
1answer
49 views
QGIS Grid not displaying correctly
I'm trying to create a map from a specific province in Argentina in QGIS 3.10. I am trying to create a map showing multiple coordinates showing hail fall data exported from a csv file and projected on ...
2
votes
2answers
60 views
ORDER BY with GROUP_CONCAT DISTINCT in QGIS3
There are two areas S1 and S2. Every area was visited two times to collect bumblebees. I want all species that has been found on each area as a comma separated string in alphabetical order.
area| ...
4
votes
1answer
54 views
QGIS: Style polygon outline as a dashed line with an inner gradient
Is it possible to create a polygon outline as a dashed line with an inner gradient (see image #1)? Currently I have a hack job that sort of works (shapeburst fill with a dashed line above in the ...
1
vote
1answer
35 views
For loop to buffer shapefile at multiple distances, add each to the layers window, style & save to geopackage; PyQGIS
Can someone help me straighten this code out. I want to create three buffers, at 100, 250 and 500m respectively and add these to the contents table. I've tried creating a for loop but not having ...
2
votes
1answer
15 views
QGIS - About Ignore Getmap/Gettile URI reported in capabilities
Some WMS are working after checking the 1st option below. Can you suggest a resource or someone with knowledge of what exactly this option changes and how it makes WMS work?
1
vote
1answer
31 views
"An error has occurred while executing python code" on QGIS startup (3.16.15)
I had installed QGIS 3.16.15 through OSGeo installation package and began receiving this error message when starting QGIS. I completely uninstalled using the OSGeo advanced installation package, and ...
4
votes
1answer
82 views
Unable to save my temporary layer
I am getting the following error while saving my temporary layer.
Traceback (most recent call last):
File "C:\PROGRA~1\QGIS31~1.14\apps\Python39\lib\code.py", line 90, in runcode
exec(...
2
votes
0answers
35 views
Can I build a QGIS query based on the boundaries of a clipping polygon?
Several times a year I download a very large shape file which contains details of the road network of my home state. That shapefile (I'll call it the master file) is regularly updated by the provider,...
1
vote
1answer
28 views
Extracting values from bands in raster where one band has two values using QGIS
I am working with QGIS and have a raster file with two bands. Band one contains two values, event types, and Band 2 contains a date where the amount of a Band one event occurring sums up.
An example ...
0
votes
0answers
25 views
ERROR 1: PROJ: tmerc: Invalid latitude
Im trying to warp(reproject) a raster layer to EPSG 4647 and keep getting the Error above. It works when I'm just right-clicking on the layer and set the CRS (it moves to the right position). But in a ...
1
vote
0answers
49 views
Geometry error present only when writing shapefile to disk in QGIS
I have a complex shapefile that I am trying to use for a Difference spatial operation in QGIS (Madiera 3.4). When doing that I received an invalid geometry error.
Using the QGIS Check Validity tool ...
1
vote
0answers
33 views
How to make pie charts out of categories based on rules
I am trying to make an animation with the temporal controller of the locations of animals on specific days and would like to display the proportion in each location. The data are in a text-delimited ...
3
votes
1answer
43 views
Prevent custom Processing Algorithm from returning output on error
In my script I make a copy of input layer and perform some actions on it. I can't figure out how to stop QGIS from returning the output layer on error. I've tried returning nothing, but if parameter ...
0
votes
1answer
33 views
Point geometry intersects line geometry not working in PyQGIS
I have two geometries, one is Line Other one is Point.
I tried find intersects between features
QgsGeometry(point).intersects(QgsGeometry(line))
I have two cases:
case1: if point placed on line ...
1
vote
3answers
57 views
Adding and filtering layer with map canvas extent using PyQGIS
I'm creating a small QGIS3.16 plugin with PyQGIS.
I'd want to add a vector (PostGIS) layer to QGIS, and immediately filter it with the QGIS canvas extent.
I found the QgsFeatureRequest(rectangle:...
2
votes
2answers
41 views
Connecting QgsCheckableComboBox Qt Signal
I tried to connect Qt signal of QgsCheckableComboBox when checkedItemsChanged.
I tried below:
def showEvent(self, event):
print("show event")
self.loadLayersToCombox()
self....
6
votes
1answer
99 views
Inconsistent behaviour of getFeature() and getFeatures() when accessing CSV table with no geometry using PyQGIS
I load the following CSV data into QGIS 3 (specs below) as a table with no geometry using default options.
"V1","time","V2"
-49,"2021-12-28T00:12:17.725753Z",13....
2
votes
1answer
61 views
Custom feature form with python logic unexpected behavior
I'm using QGIS 3.22 trying to go through a tutorial (3.16 training manual) and I followed the popular Nathan Woodrow's blog setting custom form with python logic where I changed the PyQt4 imports for ...
3
votes
1answer
50 views
Deformed shapes after using wedge_buffer as Symbol layer in QGIS
I'm trying to display "field of view" cones on the map, using Geometry Generator as Symbol layer:
wedge_buffer($geometry, dir, specs_angle, specs_distance/200000, 0)
"dir" : ...
4
votes
3answers
181 views
Skipping invalid geometries without fixing them in QGIS
In QGIS 3.16.14 I have a shapefile with multipolygons (flood risk map of the country) and another layer of points (buildings). I need to identify which of those points are inside those polygons and ...
1
vote
0answers
33 views
PyQGIS -"invalid data source" when trying to open several .shp files
I have a folder with almost 3000 subfolders, each containing several ESRI shapefiles. I tried to write a script to read each of these files, do some basic analysis on them and store new files in those ...
1
vote
0answers
46 views
PyQGIS - how to set processing to avoid bad geometry?
I am getting "feature(182) has invalid geometry" . Fixing it takes a lot of time. How do I set it to ignore bad features and keep running with Python?
processing.runAndLoadResults(
...
1
vote
1answer
38 views
How to change the default compression method in QGIS raster creation tools
Tools which create new rasters in QGIS let you set the compression method, using GDAL's -co COMPRESS= method.
The "High Compression" is set by default to "DEFLATE" (and PREDICTOR=2)...
4
votes
1answer
61 views
Absolute positions for Color Ramp gradient stops in heat map?
I'm using QGIS 3 and trying to create a heat map using GPS data acquired during various trips. I want the resulting heatmap to clearly show each location acquired at least once with some radius (...
4
votes
1answer
73 views
Vector layer with "GEOM_POSSIBLE_NAMES" not working when source as *file*
I have two CSV files having the below content.
pnt as WKT.csv:
sl,wkt
1, POINT(50.0 50.0)
pnt as PNT.csv:
sl,pnt
1, POINT(50.0 50.0)
The difference in both the file is column name in the ...
5
votes
1answer
47 views
QGIS 3.22 UI theme > layer panel > increase line spacing?
I'm using a tablet to enter some data outdoor, and QGIS was the most efficient way to do it (Roam was not compatible with the latest version of QGIS, QField not for Windows). To make it more user ...
3
votes
1answer
40 views
QGis Value Map attributes : display description instead of value as label?
Is it possible to label features with the Description of a Value Map type field, instead of its Value ?
I have a shape file layer with one of the fields defined as "Value Map" (Widget Type ...
3
votes
1answer
83 views
Applying QgsExpression to item of layout legend using PyQGIS
I am using a print composer from QGIS using python. Inside a QGIS project (.qgz, QGIS version 3.18.3), I created a print composer layout called "mylayout" and added a map and a legend. I ...
0
votes
0answers
17 views
QGIS Toolbox for Loop Routes?
I am looking for a function or toolbox which allows for generating loop routes subject to constraints. It would look something like:
Attribute
Description
Example
Network
Routing network
OSM extract
...
5
votes
3answers
98 views
Comparing two rasters, based on a complex set of rules
I am trying to compare two rasters, say A.tif and B.tif. Both correspond to river bed level changes under two different flow conditions. Now I want to produce a comparison raster having values based ...
1
vote
1answer
42 views
QGIS do not open my qgz~ file anymore. CRC-Error?
I have a couple of months' work on a project in QGIS 3.16.13 with Win 10. All my data is stored on a flashdrive.
Since yesterday when I try to open my project I receive this error message
Cannot read ...
1
vote
1answer
71 views
Assessing locations across England with at least four retail shops from four different retailers in GIS
1A: Problem
I have a dataset (point data) of 500 retail shops across England distributed in a seemingly un-random fashion (some retailers may only be found in cities or in specific regions). There are ...
0
votes
1answer
17 views
SPOT 6/7 conversion to BOA/Surface Reflectance
I am quite new to GIS and even newer to SPOT as an image source. In general, all of the other sources I have used for analysis (Landsat 7 & 8, Sentinel-2) have been corrected to BOA reflectance ...
0
votes
1answer
67 views
Return QGIS processing algorithm's results after edition
I want to create a simple qgis processing algorithm, where input layer is copied, there are some basic operations done on attributes and the resulting layer is returned. However, I encounter following ...
1
vote
1answer
59 views
How to speed up PyQGIS code for finding intersection of features in the same layer
I an deleting one of the intersecting polygons from a vector layer using PyQGIS code mentioned below. It is too slow as I have many features in the layer. Is there a way to speed it up?
index= ...
0
votes
1answer
38 views
AttributeError: 'NoneType' object has no attribute 'type' when importing file into Geopackage using DB Manager
Using QGIS 3.16
I have several Geopackages already, which I would like to import a file into and make a new layer.
I'm using the DB Manager > Table > Import Layer/File menu item. QGIS throws a ...
2
votes
1answer
84 views
Clip geometry in PyQGIS by not using a layer as an input
I have two vector geometries, geom1 and geom2. They do not exist as individual layers, but rather are derived out of additional scripting in PyQGIS.
I would like to clip geom1 with geom2.
From what I ...
1
vote
0answers
48 views
How to perform intersect or overlay_within functions using Python/PyQGIS to circumvent graphical modeler limitations? [closed]
This relates to Creating field with 1/0 values depending if point sits inside polygon in QGIS for which people provided excellent answers but unfortunately highlighted a current limitation of the ...
6
votes
2answers
172 views
Creating field with 1/0 values depending if point sits inside polygon in QGIS
I have a layer with a single polygon and a layer with multiple points. Some of the points are inside the polygon. How can I create/update a field with a value of 1 (true) or 0 (false) depending if a ...
1
vote
1answer
54 views
Testing newly installed version of QGIS with custom settings
Each time when my organization updates/migrates to the latest QGIS either a regular release or a LTR, how could I ensure that it adopts all the customized adjustments&settings from the used QGIS?
...
4
votes
1answer
57 views
Understanding difference between Pythons installed together with QGIS
There is QGIS 3.20.3 installed on the Windows 10 in the C:/Program Files/.
What is a core difference between all Pythons delivered together with QGIS? What is the purpose of each one and what are the ...
4
votes
0answers
43 views
Prevent PyQGIS from converting EPSG code to OGC URN
I'm trying to access the Sentinel Hub's WFS via PyQGIS. Here's my code:
base_url = 'https://services.sentinel-hub.com/ogc/wfs/<my_service_endpoint>?'
params = 'SRSNAME=EPSG:4326&TYPENAMES=...
1
vote
1answer
30 views
How to drop field from algorithm output in QGIS graphical modeler (drop fields does not work)
I have built a process in the graphical modeler which uses several temporary outputs. The resulting CSV is fine but it contains an unneccessary field from the HubDistance algorithm (HubName). I'd like ...