Questions tagged [qgis-3]
for questions specific to the 3.x series of QGIS.
2,325
questions
2
votes
1answer
34 views
Show all contour line labels in Layout in QGIS
I created a map with labeled contour lines. When I am now adding the map to the layout view not all labels appear (e.g. 2000, 2500 and 3500 meters has a label, but not 3000)
[.
In the original map ...
1
vote
0answers
15 views
the basemap of QuickMapService changed when exported from print composer layout? [duplicate]
I was trying to export the layout, which was supposed to be like this:
However, the exported image became untidy and unclear because of many secondary information were added, such as those tiny road ...
0
votes
0answers
27 views
Cannot find CRS of MODIS and Reproyect
I am new to QGIS. My project CRS is EPSG:4326 and I have five rasters in this CRS.
The problem comes when adding a raster file from MODIS. I am downloading the world GEOTIFF image from :
https://...
-1
votes
0answers
22 views
Color ramp drop down down options missing in QGIS 3.4
Shouldn't there be options like Spectral when I press the drop down menu on the Color Ramp of the Symbology?
Specs:
OS: Mac, OS Sierra 10.12.6
QGIS version 3.4.14-Madeira
0
votes
0answers
17 views
RQGIS3 : AttributeError: module '__main__' has no attribute 'RQGIS3'
I am trying to use the RQGIS3 package to access QGIS3 functions from R, and although briefly I had things working (mostly), running the following code:
library(RQGIS3)
qgis_env <- set_env("C:/...
1
vote
1answer
45 views
QGIS SAGA “Kriging” tools doesn't work
I try out different methods of point interpolation for a digital terrain model. For this purpose I tried to run the "ordinary kriging tool" from the SAGA Tools with QGIS 2.18 and QGIS 3.2.
When I run ...
0
votes
0answers
18 views
Switch QGIS measurement back to Cartesian
I am unable to get QGIS 3 to give me areas in Cartesian measurements.
My project is in CRS 27700 BNG and when using $area in the attribute table the values are returning in ellipsoidal measurements ...
0
votes
0answers
29 views
Set a SVG icon for only one feature using PyQGIS
In my QGIS3 Plugin I have a multipolygon layer. I need to set programmatically a SVG icon for a selected feature, without changing the style of the other features. Basically I need to replicate what ...
2
votes
0answers
21 views
PyQGIS 3: Create a layer with a primary key
I have written a plugin for QGIS that is importing some data. In this plugin, I can create a memory layer for the data like I have described here https://gis.stackexchange.com/a/349354/10123, but how ...
0
votes
0answers
33 views
Combine 8 different shapefiles into 1 with combined attribute fields
I am working on a project where I want to add the attribute fields of 7 different shapefiles into 1 base shapefile. Specifically, I have a parcel map of a city, and I want to append attribute fields ...
2
votes
0answers
30 views
Smooth contour lines/correctly extract contour lines from a DEM in QGIS
I have a DEM obtained as a result of the interpolation of elevation points TIN Interpolatin:
I extracted the contour lines in QGIS and the result is this:
After I tried to apply the Line Smoothing ...
1
vote
0answers
36 views
Not able to use previous fields for default values expression
I've got the following problem : I have different periods (selected with a drop-down menu, which is like "Paléolithique", "Mésolithique"... etc) and I'd like the fields "Année inf" and "Année sup" to ...
0
votes
0answers
18 views
QGIS version 3.10 full display screen not visible
I'm a brand new QGIS user.
The QGIS 3.10 display screen won't let me view the bottom of the display. I'm using a Dell laptop with 64 bit O.S and Intel processor.
I tried reducing the resolution but ...
3
votes
3answers
59 views
Copy feature between layers with PyQGIS
I am new in PyQGIS and am having trouble programming how to copy features between layers.
Goal: from a robust layer (with more fields) copy its features to a 'simple' version layer.
from qgis.core ...
4
votes
1answer
36 views
Does QGIS 3.4 locks the row while editing the postgis data?
I want to know if QGIS locks the row of a postgis table for editing or can this behavior be force implemented? Suppose there is another user who wants to edit the same row-- this must not be allowed.
1
vote
0answers
21 views
Exporting geodatabase layer to shapefile fails in QGIS [duplicate]
I'm attempting to export a single layer from a geodatabase to a shapefile. The export fails at the same point, 71%, with this message (I'm only displaying the first few lines),
Export to vector file ...
1
vote
2answers
38 views
Saving a vector layer as .xyz with PyQGIS 3
I'm writing a standalone script for QGIS. In this script I want to import a couple of text files saved as .xyz. When I import them in QGIS I have to use "Import layers as delimited text", thus they ...
0
votes
0answers
25 views
Filtering layers in QGIS atlas while displaying them in the canvas
I would like to create and atlas that instead of displaying all the features within a layer, it only displayed those related to the atlas.
Certainly, I could do as this excellent answer suggests, ...
0
votes
1answer
55 views
QGIS 3.10.2 - Install PostgreSQL and PostGIS
QGIS 3.10.2 in Ubuntu 18.04.
I'm having problems installing PostgreSQL and PostGIS following the instructions here: Installing PostGIS under Ubuntu.
This doesn't work, 'postgresql-9.1-postgis' isn't ...
5
votes
1answer
60 views
When to recompile resource.qrc with pyrcc5
In QGIS3 plugin tutorials that use the plugin builder, it says to run pyrcc5 before importing the plugin.
After what changes should pyrcc5 be run again? I have managed to modify some plugins by ...
5
votes
1answer
117 views
Calculating field AVG from B layer 3 nearest points to each A layer point
I wonder how to calculate statistics (in my case average) of one point layer field (let say B layer) and assign them to each point of A layer.
Statistics should be calculated from 3 nearest B layer ...
4
votes
1answer
77 views
Organize all dialogs in one package QGIS 3 Plugin
To organize better the code in my QGIS 3 Plugin, I tried to put all dialogs in one package called dialogs, but when I open QGIS it says ModuleNotFoundError: No module named 'dialogs'
This is the code ...
1
vote
1answer
32 views
A simple way to merge lines separated by a space in QGIS
In QGIS after creating contour lines by extracting them from a DEM (Extraction > Contour) and smoothing them (Line Smoothing) I noticed this situation:
In order to smooth out the corners ...
5
votes
2answers
91 views
Create buffer in meters in WGS84 layer using PyQGIS
In my QGIS 3 plugin I have this code that returns the list of all features intersected with a buffer calculated from two input values: the ID of the feature in the center of the buffer and a radius ...
1
vote
0answers
18 views
Lizmap - QGIS server - PostgreSQL error layer not valide
l installed Lizmap in Windows 10 but a problem is that I haven't the edition button and can't display layers from PostgreSQL. I have a "service non disponible" with "layer not valide" error in QGIS ...
2
votes
0answers
25 views
Create a report with filter from different layer using Atlas
I have the following scenario:
Layer ‘grid’, with a field called ‘number’
Layer ‘log’ with field called ‘number’ in common with ‘grid’ layer and another field called ‘date’
Layer ‘problem’ with field ...
3
votes
1answer
36 views
Filling layer attributes field from Python list using PyQGIS
I have a QGIS3 layer which has an attribute column indicating the id of each features. I want to add two more fields and fill them with some values taken from a python list.
The list is something ...
1
vote
1answer
40 views
QGIS Plugin Running in QGIS 3.10 but not in QGIS 3.4
I am new to QGIS, need your help in fixing one problem. I created a Plugin for QGIS. While creating it, I worked on QGIS 3.10 LTR version for which my plugin is working perfectly.
Now when I shared ...
3
votes
1answer
41 views
Buffer output is different for same attribute value in different layers (QGIS 3)
I have two line layers with almost the same attribute table. And I want to create a buffer with "variable distance buffer" from the line's attribute "raiometade" and "raio_metade".
Layer 1 is ...
2
votes
1answer
42 views
Convert relative coordinates into absolute ones having only one absolute coordinate in QGIS
I have a layer of points with relative altimetric heights from a survey carried out with a Differential GPS. I know the absolute coordinates of only one point (EPSG:4326 WGS 84 ), the other points ...
1
vote
0answers
18 views
Create bookmark in QGIS print composer
Three and a half years ago a user asked if it is possible to add bookmarks to the print composer in QGIS. The link is here.
The answer was that someone posed a feature request for this feature.
I ...
0
votes
0answers
25 views
Using qgis.core in anaconda environment
I am trying to use qgis.core in a Conda Environment with qgis, PyQGIS and Python 3.7 installed.
I get over an over the next error:
File "C:\Users\dg\.conda\envs\env_p3\Library\python\qgis\core\...
-1
votes
1answer
46 views
Problem with “On the Fly Projection” (OTF) in QGIS 3.4 when upgrading from QGIS version 2.8 [closed]
I just switched from QGIS 2.8 to 3.4. On the fly projection does not appear to be working. None of the Google searches I do provide help. Looks like most folks want to turn OTF off, and it sounds like ...
2
votes
2answers
27 views
Reprojecting QgsPointXY
I am writing a plugin to import some files into qgis. The files initially have coordinates in lat lon, but I want to reproject them to a local projection during the import.
So, I can set the CRS on ...
2
votes
1answer
28 views
Shortcut to activate and deactivate a layer filter
I'm looking for the fastest way to filter and unfilter a layer in qgis 3.
My current workflow is too tedious: right click on layer / filter / write filter or delete filter
My final goal is to see ...
4
votes
1answer
51 views
Align labels on a vertical line
I have a series of contour lines with relative elevations (Z value). I am trying to align the labels so that they are all on the same imaginary line.
It's a process that I usually do with Autocad ...
-1
votes
0answers
31 views
How to change the unit which is in meters to pixels for a raster image in QGIS3?
I have a raster image which I have opened in QGIS 3.
These are the steps I follow: Right click on the image -> Information tab
Information about the image is displayed, which shows:
Unit ...
2
votes
1answer
132 views
Where is the “Intersection” tool located in QGIS 3?
I would like to generate the intersection between lines and polygons lines and polygon in QGIS 3 and extract the id number for each line. I would like to assign a red color to the resulting lines ...
1
vote
0answers
36 views
Is points to route still available in QGIS 3.4?
I need to do the same thing as the post here as I need to create polylines based on given points with sequence attribute, and networks, but I cannot find the tool in toolbox:
my point data and ...
0
votes
1answer
41 views
QGIS Vector Layers
Why does the Columbia River nearly perfectly follow the OR-WA border? What characteristics do vector layers have that allow this?
1
vote
1answer
91 views
QGIS 3.10.2. Projection Problem
Updating QGIS to the new version I have serious projection problems:
I am loading a shape-file from STATISTIK AUSTRIA (an offical authority in Austria) with the following projection:
PROJCS["MGI / ...
0
votes
0answers
27 views
Trouble building route __file__ is not defined [duplicate]
I want to change this address:
"C:/Users/SENARA/AppData/Roaming/QGIS/QGIS3/profiles/default/python/plugins/RiegoSenara/LogoSenara.png"
and use this:
os.path.join(os.path.dirname(__file__),"...
1
vote
1answer
27 views
3DES Import raster layer - Datum appears to convert vertical units twice in QGIS
I import a 3DES IMG raster layer formatted in NAD83 metric vertical units (EPSG:26911) from the USGS 3D Elevation program. When I look at the elevation values in the layer properties, they appear to ...
0
votes
0answers
12 views
Force pyramid zoom level on any WMS, WMTS or XYZ?
Is there a way to lock the view to any tileset level regardless of the scale, e.g remain at zoom level 12 whether the scale is 1:250000 or 1:62500, so that features like text and paths appear at ...
2
votes
0answers
34 views
Grouping points by attributes from field with possibly many values
I have a shapefile "cities" with one unique city_id for each city (geometry polygon, although not relevant here) :
city_name ; city_id
New-York ; 0001
Paris ; 0002
London ; 0003
And a ...
3
votes
1answer
43 views
Shapefile stopped displaying polygons and gives error: 'No extent could be determined' in QGIS 3.10
I have been using a shapefile as a main data layer since Jan 2018 in a project, it forms the basis of several duplicate layers, it has been working fine until today.
Now 95% of the polygons are no ...
1
vote
0answers
48 views
Run PyQGIS script always - in the background
How to always run a PyQGIS, in the background?
In my case, I want to delete "feature A", the polygon, that have a "attribute X", if feature B, the lines, that have "attribute X" as well.
0
votes
1answer
62 views
Adding layer to canvas crashes QGIS
I am having some difficulties in adding a layer to my canvas or even to main project. I create a plugin in QGIS 3.10. This plugin has a table of contents and a canvas to open some maps. I search and ...
1
vote
0answers
21 views
QGIS 3 can not set a relative path to Form UI file
I have created a custom form ui file, and everything is working fine if I pass the absolute path of my ui file to QGIS.
But I need to use the relative path, because I need to package the project file ...
2
votes
0answers
33 views
Close gaps between some polygons, which are adjacent in reality
I have tens of thousands of polygons (farmer plots) which have been measured while on the fields. This has caused plenty of gaps between some polygons, which is not the reality. I would need to close ...
