Questions tagged [qgis-3]

for questions specific to the 3.x series of QGIS.

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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 (...
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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
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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
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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
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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
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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
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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?
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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
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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(...
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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,...
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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 ...
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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 ...
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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 ...
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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
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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 ...
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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 ...
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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:...
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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
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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....
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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
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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
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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 ...
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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 ...
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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( ...
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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
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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
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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 ...
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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
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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
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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 ...
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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
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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
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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 ...
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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 ...
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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
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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
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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
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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
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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 ...
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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
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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
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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
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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
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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 ...

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