Questions tagged [qgis-3]
for questions specific to the 3.x series of QGIS.
3,053
questions
1
vote
0answers
12 views
Output layers order in QGIS Graphic Modeller (algorithm execution order / dependencies)
I created a simple model in QGIS graphic modeller that takes in input parameters like drive time ranges and start location and outputs 3 styled layers including "start_point", "...
0
votes
0answers
21 views
Merge GPX tracks with PyQGIS / Python
I am having problems with my Python script (completely new to PyQGIS).
I want to import all GPX-files from an given directory to QGIS, then change the Geometry type from MultiLineString to LineString (...
1
vote
1answer
31 views
How to Access the Current Value of the Scale Factor of a Map as a Variable (eg $map_scale) in Print Layouts in QGIS
Does anybody know how to access the current value of the scale factor of a map as a variable (eg $map_scale) in print layouts in QGIS?
I'd love to put the scale factor in my maps...
3
votes
1answer
34 views
Selecting a point and auto selecting a polygon in another layer in QGIS 3.14
I'm using QGIS 3.14 Pi and here's my scenario. I have a layer of points and each points contain a numerical value code, let's say it's 123. There may be multiple points with the same code value. In ...
0
votes
0answers
25 views
Creating DXF from WFS Saves Slowly
I'm currently required to periodically pull cadastral lines from a WFS server and my current methodology is resulting in slow saves.
I first query a very large layer within the WFS with a known ...
0
votes
1answer
31 views
Splitting feature into layers which are overlapped in same layer in QGIS
My script needs to select each feature in layer. While selecting features I found some of feature are overlapped. Feature can be selected but cannot highlight in map canvas.
Is there any plugin or ...
0
votes
0answers
15 views
QGIS 3.14 custom forms cache
QGis 3.14 Custom Form Cache
I'm using an *.ui file for a custom form in the layer properties dialog and everything works fine.
Once the form is open, i change the size of the form with the mouse from ...
2
votes
1answer
50 views
Add scale bar to canvas using PyQGIS
Is it possible to get the decorator scale bar onto the map canvas inside a standalone PyQGIS application? It is possible to get a scale bar on the QGIS Desktop version by View -> Decorations -> ...
0
votes
0answers
34 views
QGIS query builder with Unicode Language complicated view and unreadable statements [closed]
Complicated view and unreadable statements.
The problem is when I write query statements I cannot read it or edit it because of complex view as you see in the picture in red square .
here same ...
3
votes
2answers
79 views
Select polygons containing particular attributes from points layer
I have thousands of polygons (buffers) in a single layer and I have a points layer containing tree species. The tree species points shapefile has an attribute called Tree_Type. I need to select only ...
2
votes
0answers
40 views
+50
Overwrite existing raster layer using PyQGIS
QgsVectorFileWriter allows you to overwrite an existing layer with your output, but I have not found a similar option with QgsRasterFileWriter. Here's my code that is writing a raster layer out to a ...
2
votes
1answer
39 views
Filtering out attributes fields of a vector layer using PyQGIS
I have a vector layer with 50 columns/fields. I have been trying to find a way of selecting 6 columns of particular interest (by name or index) and then creating a new layer from that selection, such ...
1
vote
0answers
26 views
Error while exporting data through Mappia Publisher in QGIS 3.14
I installed Mappia Publisher in QGIS 3.14 and try to share some data. It works until almost the end. It gives me a Python error. I do not know why. Also, it takes me almost two hours to run.
Finished ...
0
votes
0answers
18 views
JPEG file wont open in QGIS 3.10 but does in QGIS 3.4
I recently made the upgrade to QIGS 3.10 from 3.4 and I am having trouble loading a JPEG image that previously worked fine in 3.4. In the georeference window when I try to open the raster I am given ...
0
votes
0answers
32 views
V.Clean is not giving output In QGIS 3.14 Pi
I was trying to clean by removing sliver lines between set of polygons in my KML file. But unfortunately I am getting following error:
QGIS version: 3.14.15-Pi
QGIS code revision: d5114d2cfa
Qt ...
1
vote
0answers
19 views
Setting the 3d view function for a polygon layer
I am trying to create a 3d model of an archaeological site on QGIS. I had some contourlines, I made them polygons using the "polygonize" plugin and I categorized the polygons with a colour ...
0
votes
0answers
23 views
How to import CSV (downloaded from Google Drive) with polygonal geometry data, into QGIS?
I formerly used Google Fusion Tables but due to the product downturn I had to bulk-download a backup copy of my data. Right now I have them all saved in CSV format.
I have attribute columns in these ...
0
votes
0answers
17 views
Different scale for x and y in a QGIS map layout
I'm making some geological cross sections with the geoscience plugin. I have been able to do this and I can make a print layout where I have my cross section (which the plugin makes in x-y space where ...
0
votes
0answers
13 views
Moving the View during Temporal Animation in QGIS 3.14
I'm very excited about the native support for temporal elements in QGIS 3.14. I have enjoyed the detailed tutorial by developer Nyall Dawson here, which gives nice overview of its many possibilities. ...
-1
votes
1answer
38 views
Detect yellow spots on an image [closed]
I have a big raster image (12 GB) and I would like to detect yellow stains on it. I did try the Zonal Statistics but it is almost impossible to find the right parameters in order to detect the stain. ...
0
votes
0answers
29 views
Create a new shapelayer - how to delete a wrong node QGIS 3.14 [closed]
I want to draw a polygon in a new shapelayer. Sometimes I draw a wrong node and I cannot delete it. I have to delete the whole layer and must start again.
I wonder if there is a shortcut or something ...
2
votes
0answers
30 views
No transform available between EPSG:2100 and Unknown CRS
After upgrading from 3.04 to 3.10 my QGIS projects keep reporting "No transform available between EPSG:2100 and Unknown CRS" although the project settings dictate that EPSG:2100 should be ...
1
vote
2answers
99 views
Problems with loading Plugins (processing and other plugins)
I have the following python errors when starting the QGIS 3.14:
2020-10-21T09:21:57
CRITICAL Traceback (most recent call last):
File "C:\OSGEO4~1\apps\Python37\lib\site-packages\osgeo\osr.py&...
1
vote
0answers
16 views
QGIS: spatialite error: no such function: st_functionname() in specific qgis project
From one day to another I can't import any queryresults that contain a spatialite function as layer from DB manager anymore despite the query concluding successfully in DB manager.
select * from table
...
0
votes
0answers
41 views
Calculate multiple fields from joined fields
QGIS 3.14.
I just joined a table to my a layer with already multiple fields.
I want to replace the values in all the original fields with the values in the joined table.
I'm searching a way to ...
4
votes
1answer
88 views
Processing tool to invert/switch selection in Graphical Modeler
I want to switch/invert a selection in Graphical Modeler so I'm looking for a processing tool to do so. In ArcGIS, this can be done with "Select Layer By Attribute" with Selection type: ...
1
vote
0answers
40 views
QGIS Temporal Controller with raster data
Starting from QGIS 3.14 TimeManager is dead, long live the Temporal Controller!
There are a lot of tutorials out there how "Temporal Controller" deals with vector layers, which looks nice. ...
3
votes
1answer
64 views
Converting list into field with PyQGIS
I am trying to convert a few lists into fields.
I have no problem creating the fields. I just don't have any idea on how to fill them.
if result:
layer = self.dlg.comboLayerLine.currentData()
...
1
vote
1answer
20 views
Query Result message returns 0 rows but browser shows results
I am using the Layer filter tools in QGIS version 3.14.1 Pi. (Right Click on layer > Filter)
The source data is a Mapinfo .tab-file on a Server.
When I put in my filter query, "Field_name"...
0
votes
0answers
31 views
Using geography cast as geometry in QGIS No SRID in Airports table. Other table have geom and is 26986
I trying to add a layer into the map in QGIS. It will execute the SQL and show the answer but will not add it to the map. It states there a geometry error. I type cast geom::geography it should allow ...
1
vote
1answer
30 views
How to put QgsCheckableComboBox() into standby
I'm trying QgsCheckableComboBox() in my simple python script in QGIS. How to pause code execution while a comboBox-window is open (like a dialog box)? In my example, I want to ensure that the print() ...
1
vote
0answers
22 views
Refreshing VRT raster layer using PyQGIS
I'm working a lot with GDAL VRT raster layers in QGIS 3.14, often changing the file content while viewing the rasters in map canvas. When I zoom or refresh the canvas in QGIS 2.18, all modified VRT ...
5
votes
2answers
164 views
Align existing points along a line with even spacing
I have a number of existing points which are snapped to a line, however they are unevenly spaced along the line, like this:
How do I align them so they are evenly spaced out along the line like this:
...
1
vote
2answers
51 views
Buffering river but it came out as circle
I'm buffering a river using QGIS 3. I am using 30 meters for my buffer. My problem is the buffers came out as a circle, not following the lines.
This is what happens during my buffer
0
votes
0answers
17 views
QGIS 3.10 Layout Manager not printing Google Satellite background
I am trying to compose a layout with Google Satellite as background. I am trying to add such background both with XYZ tiles utility and with QuickMap Services plugin. In both cases the layer is ...
2
votes
1answer
36 views
No Plugins available in QGIS on Mac
I downloaded the 3.10 version of QGIS onto my Mac (version 10.15.6). There are no Plugins available in the programme. Do I have to download plugins from somewhere else?
Also, in the Raster Menu, the ...
2
votes
1answer
29 views
CRS for Ellipsoid Measurements
I noticed within the "Project Properties" there's an option for, Measurements --> Ellipsoid. What should this setting be configured to?
From what I read online, if this is set incorrectly,...
1
vote
1answer
34 views
Shortest path (point to point) when filling out coordinates in boxes
I am using the processing toolbox interface to launch the "Shortest path (point to point)" command to connect two points using a line network layer (see attached photo).
If I fill out the ...
0
votes
0answers
12 views
Why is ArcGIS Feature Service layer incomplete once added to QGIS?
I'm running QGIS3 and I'm trying to a add property cadastre layer from a publicly hosted ArcGIS Feature Service connection. The connection works ok, but when I add the cadastre layer, not all polygons ...
5
votes
2answers
49 views
Map extent matching permanently main canvas extent
Refreshing the map extent on QGIS's composer requires to click on Set map extent to match main canvas extent
I was wondering if there was a possibility to have a map extent (in the composer) that ...
0
votes
0answers
17 views
Vector Tiles: do the zoom levels depend on the projection?
For Mercator Projection I found a table of zoom levels and their corresponding scale. I suppose that the number of zoom levels and the corresponding scale change when using another projection for Map ...
0
votes
0answers
14 views
Rasterize(Convert Points to Raster) :UnicodeDecodeError in QGIS3
I used Rasterize in QGIS3 to convert points to rasters. The source file of the point layer used is as follows:
But clicking Run displays the following error message:
Traceback (most recent call last):...
1
vote
1answer
54 views
Authentification failed when using SentinelHub Plugin in QGIS
I downloaded SentinelHub v2 plugin into QGIS 3.14.
When I want to log in with my ID (from SentinelHub / Configuration Utility / ID) it says "Authentification failed, check your credentials"....
1
vote
0answers
27 views
Using various script forms in Linux QGIS 3.12
In the last few weeks, I have noticed that various script forms in QGIS (3.12, Linux Mint 19.3) have strange cursor behaviour. Spaces in scripts are unevenly represented on the screen. This is hard to ...
0
votes
2answers
34 views
Auto Trace Installation Error in QGIS 3.8
My QGIS 3.8 doesn't support Auto Trace 1.0.6 or 1.0.7. My pc has a 64bit Windows 10. How can I solve it?
8
votes
4answers
769 views
Quickly review one by one all the features in a dataset in QGIS
I have about 400 features in a point dataset. I would like to (quickly) visually check their locations one by one on the map. For now, I open the attribute table alongside the map. I select the first ...
10
votes
2answers
134 views
Rule-based symbology based on current selection in QGIS
I have two oracle layer (point(p1) and polygon(pl1)). I want to build a rule-based symbology which is based on current selection on two cases:
Case 1- When I select a point from table p1, I want that ...
0
votes
0answers
67 views
Problem with massive data importation to PostGIS/PostgreSQL
I need to import a huge SIG data into PostgreSQL (my shapefile table have almost 1.700.000 rowns and 43 columns).
I'm using PostgreSQL 12.4 and PostGIS 3.0.x, that came together with PostGIS Bundle 3 ...
1
vote
1answer
32 views
Saving each feature in PNG format along with map canvas in certain scale using PyQGIS
I want to export each feature by zooming to certain scale (eg 1:25000 where feature will be inside map canvas) and save into PNG format. I know function
iface.mapCanvas().saveAsImage("image_path&...
2
votes
0answers
32 views
Getting characteristic high points from DEM
I use QGIS 3.14 and I have a DEM file which I'd like to use to get a point layer with most characteristic high points from that DEM. So every top of the mountain, hill, hillock, low etc should be ...
