Questions tagged [qgis-3]
for questions specific to the 3.x series of QGIS.
1,846
questions
0
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0answers
6 views
/{z}/{x}/{y} Template for QgsRasterLayer in PyQgis3
I took the following code which works in QGIS2 and changed QgsMapLayerRegistry to QgsProject for QGIS3. Running the code in QGIS 3.8.3, the layer is created, but the tiles do not display. The Scale ...
1
vote
0answers
17 views
Extract borders from country polygons
I'm trying to convert a polygon GeoJSON of countries into a line layer that contains only the borders. It should not contain the edges of the polygons that border the ocean (in my polygon dataset, ...
0
votes
0answers
7 views
QGIS 3.8 MacOS - Connect to Oracle
I know that prior releases of QGIS (2.x releases) did not include drivers to connect to Oracle databases, and one would need to compile QGIS themselves with the proper Oracle drivers included if they ...
0
votes
0answers
16 views
Overlaying scanned maps with different scales point to point in QGIS? [on hold]
I have different scale scanned nautical charts of the same area, I have georeferenced these using georeference GDAL in QGIS but when I am overlaying these maps the common point features are not ...
1
vote
1answer
36 views
Create QML Widget with a picture in Attributes Form
I would like a Qmlwidget in the Attributes Form to show a picture.
So far I have created the basic qml for a blue rectangle:
import QtQuick 2.0
Rectangle {
width: 100
height: 100
color: "...
0
votes
0answers
31 views
Distance matrix only for a specific rule [QGIS]
I am having a hard time using distance matrix vector tool in QGIS for a specific need.
I know you need to have two different point layers in order to get a distance matrix, so far so good.
But as I ...
1
vote
0answers
23 views
How can to find tolerance in topology?
I am working with Topology plugins in Qgis 3.8, but I don't see tolerance in topology. I hope to get help. I have attach images.
3
votes
0answers
31 views
Testing nodes connectivity
I'm working on a shapefile of Brussels (QGIS 3). This shapefile contains all the streets in Brussels, see below.
With the attribute table, I have an "X" and "Y" position for each line (debut and end),...
4
votes
0answers
35 views
Generating slightly curved arrows in QGIS 3
In Geometry Generator in Symbology in Layer Properties, the following expression works, but the result is not satisfactory due to the middle point fixed coefficient 1,1:
make_line (
start_point(...
4
votes
0answers
49 views
Running and scheduling processing jobs in QGIS 3?
Basically I want to write a script that would run on a daily basis on QGIS 3. This tutorial seems to have exactly what I want but the tutorial only works for QGIS 2.
QGIS Tutorials and Tips | ...
3
votes
1answer
61 views
QGIS make line attribute
How to automatically load all my attribute values into a layer after manually adding an attribute field? Or how to achieve the effect of PointConnector plugin in a more flexible that retains ...
3
votes
0answers
28 views
Restricting label/line drawing to 45 deg. lines?
I've followed this tutorial to be able to move label positions and draw lines to connect them to the label dots, but I'd like to restrict the line drawing to 45˚ angles.
Is there a way to do that? I ...
0
votes
0answers
23 views
QGIS 3: Browser Widget slows QGIS
I read a lot of speeding up the browser widget, but nothing seemed to help me.
as long i have it closed qgis is fast but if I open it all actions slows down.
My project is on a local ssd - fast dir ...
1
vote
0answers
43 views
Automatically update records in layer based on changes in another
I am using QGIS and I have two layers the first one is "Reading" layer with the attribute details
The second layer is "Reading_History" layer with the attribute details
I want to use the expression ...
2
votes
1answer
66 views
Splitting line with equal end parts
In QGIS 3.8.2 I would like to split line into equal segments.
The issue is, that v.split splits the line into the required segments, except the last segment.
I would like to split the line into equal ...
0
votes
0answers
21 views
QgsVectorDataProvider addFeatures doesn't take attributes
I'm trying to add features in empty QgsVectorLayer with addFeatures, I got the layers without attribute:
def create_features(input_file, wid, hite, focal_lgth):
features = []
filename_def = {
...
1
vote
1answer
30 views
Finding unconnected polylines and connecting them using QGIS?
I have a pipeline network, during manual digitization have a lot pipes unconnect.
Is there any way to find pipes unconnect and edit it in QGIS?
0
votes
0answers
35 views
local variable 'elevation' referenced before assignment"
I had got this error when I try run Qwater model.
"2019-09-15T19:47:05 WARNING Traceback (most recent call last):
File
"C:/Users/OS10/AppData/Roaming/QGIS/QGIS3\profiles\default/python/...
-1
votes
0answers
12 views
QGIS Server - fragile regarding file formats? [closed]
This might seem an overly general question, but...
Is qgis_mapserv.fcgi known to be fickle about its data sources?
If so, which ones are known to be without problems?
I've been experimenting for ...
1
vote
0answers
28 views
How to join PyQGIS scripts parts?
On my way to find a solution to This Question, I´m trying to merge some automatic generated script with This example.
My thought is that after the last step, I could insert the script that does ...
2
votes
1answer
47 views
Comparing between layers name and merging layers having same name using PyQGIS?
I'm trying to write python script in QGIS to merge layers having the same name.
To do that I specify the name of layer in the script, so all layers having this name, will be merged. However, since ...
1
vote
1answer
20 views
Can't see multiple layers when adding a WMS
I am using QGIS 3.8.2.
I have a WMS (https://openwms.statkart.no/skwms1/wms.topo4.graatone?) that I want to add, and in Arcgis it lists several layers (33 total) in the table of contents. When I add ...
4
votes
1answer
32 views
ModuleNotFoundError when installing plugin from zip
I have a plugin that I have developed for work and we have less than 10 users that will want to use it, so rather than publishing on the QGIS online plugin repository (https://plugins.qgis.org/plugins/...
1
vote
0answers
12 views
QGIS WMS mapserver not showing all layers
I'm publishing a map via qgis_mapserv.fcgi and the WMS behaves strangely, without giving me any errors or other clues as to what might be wrong.
I am wondering:
is the problem with using GeoJSON as ...
0
votes
0answers
20 views
Cut polygon by line QGIS [closed]
I am looking to split a polygon by a line layer that bisects the polygon in QGIS. Ideally this will be used to split a tiger/line county shapefile so that it ends at the coast instead of in the ocean. ...
0
votes
0answers
20 views
QGIS Export REST API
I am looking for any API that can export/expose QGIS Map data as an REST API to be consumed by front-end Web GIS application
Can you suggest a suitable solution for same.
2
votes
1answer
29 views
Measure Line while editing in Edit Mode (Workaround?)
It's unfortunate that QGIS does not allow the use of the Measure Line tool while activiely editing something with Add feature or Vertex tool. As soon as one of the latter tools are switched on the ...
0
votes
0answers
19 views
QGIS 3.4 crashes on exit
Every time I exit QGIS 3.4 recently insalled I get this message.
Crash ID: 41bd556bfb4cb3857ad8b303df49560eb10217ac
Stack Trace
proj_lpz_dist :
proj_lpz_dist :
QgsCoordinateTransform::...
1
vote
1answer
36 views
Polygon from QgsPoints - QGIS 3.8 python
I'm trying to create a polygon layer from 4 points that I have already defined. There issue here is that I'm always getting the following error:
AttributeError: type object 'QgsGeometry' has no ...
2
votes
1answer
34 views
How to use maximum and minimum operator in raster calculator QGIS
I would like to normalize a raster, using the raster calculator in QGIS 3.x but I don't know how to use the maximum and minimum operator. I have tried the following sequence but it does not recognize ...
2
votes
3answers
50 views
How to load external files in PyQGIS?
I have lots of models in QGIS 3.8. I´m translating them to Python scripts to still use in the Tollbox but qith reduced processing time.
Using the QGIS automatic "export model as Python script", I´m ...
1
vote
0answers
18 views
Script PyQGIS without Interface in Ubuntu
please can you help me? I tried many times to do a script of pyqgis but without interface qgis. I use QGIS 3.6.3 and Ubuntu 18.04, does Somebody know do this?
1
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0answers
24 views
'python-qgis' is not recognized as an internal or external command, operable program or batch file
As per - https://root676.github.io/installation.html - I am trying to install QNEAT3 via the OSGeo4W shell using python-qgis -m pip install matplotlib, however I am getting the following error message:...
1
vote
0answers
27 views
Layer converted into attribute
I am using QGIS 3.8. I am creating a geological map, and because I wanted to merge two different polygons, it created a separate layer. I want to convert this dissolved layer into the attribute to my ...
1
vote
1answer
48 views
Setting CRS on QGIS?
I am just learning how to use QGIS (3.4.1) and am having some issues overlaying some data (CSV file) with a QuickMapServices base map. I feel like this is an issue with the CRS, but am not 100% sure.
...
0
votes
0answers
42 views
Points from WKT File are in Wrong Location [closed]
When I load my WKT file (truncated sample below) into QGIS 3.8, the points load into the wrong location.
label,geometry
96962283,POINT(-15.43 28.30)
96963030,POINT(-15.39 28.41)
96963031,POINT(-15....
1
vote
0answers
30 views
Use of QGIS/GRASS/SAGA procedures on Geometry Generator
Im new at QGIS, started 2 weeks ago. I'm trying to automatize the display of a map and get rid of some "duplicated" layers and all the extra work. I need to know if SAGA's dissolve can be used in the ...
3
votes
0answers
44 views
Running Standalone PyQGIS Script with Multiprocessing?
Is it possible to run a standalone PyQGIS script using multiprocessing for better performance?
I'm creating 1,800 rendered map images and would like to run it across 4 processes to speed it up.
If I ...
3
votes
1answer
38 views
Geometry Generator - Straight lines not curved
I have QGIS 3.8.2 installed and started to look at the Geometry Generator. I have a layer of airline tracks and trying to create a curved line linking start and end points.
I did a lot of searching ...
0
votes
0answers
31 views
Serving a QGIS Project to Leaflet / MediaWiki Maps Extension
I'm currently serving a custom map with qgis-mapserver and that works well. However, my next step is Mediawiki integration, and for reasons of GeoJSON overlays, I must use the Leaflet option there.
...
2
votes
0answers
20 views
Getting layers path in Layer properties window in QGIS 3.4 by PyQGIS?
I'm going to know how I can get layers full path in table of contents in QGIS3.4 when my QGIS is closed and it's running such as daemon?
Rememebr: my shapefiles are in some different folders.
This ...
1
vote
1answer
41 views
Finding matching field values between two layers in QGIS?
I have two attribute tables, 1 from a shapefile layer (left) and 1 from a csv layer (right). I would like to find values in the first column ("KEY" column in shapefile layer) that appears in the ...
2
votes
0answers
29 views
Standalone PyQGIS file lock
I have a simple script for processing thousands of rasters/shapefiles. i am not able to delete temporary files, which are created by processing. I can pass them to:
'memory:output_file'
but not for ...
1
vote
1answer
57 views
Is Labeling toolbar no longer available in QGIS 3.8.2 running on Mint 19.2 Tina?
It seems the Labeling toolbar is no longer available with this version on Mint 19.2 Tina, though I have seen it on the Windows version of QGIS 3.8. Moving labels is a vital part of a large research ...
2
votes
1answer
32 views
Controlling line width at different points in QGIS [closed]
I have vector data for rivers including their width at various points. From what I have seen so far, QGIS 3.8 can set the line width only per linestring, no per segment.
Is it possible (maybe with a ...
1
vote
1answer
46 views
Line at map scale that do not vanish when zoomed out? (QGIS 3.8)
I'm drawing rivers and roads as linestrings with width set in map units from an attribute.
When zooming out, of course they vanish quickly, because 10, 20 or 100m is less than a pixel at 1:100,000
...
0
votes
1answer
38 views
Adding label to map layer by clicking feature or similar action in QGIS?
I have searched the web (including stack exchange) quite extensively and haven't found anything. I've tweaked the 'repeat' setting on the label position tab on a line layer to where it labels enough ...
1
vote
1answer
47 views
Importing DEM to QGIS?
I downloaded a DEM file (package, rather?) of the entire US from usgs.gov. It's 30GB and contains quite a few files.
Is it possible to import this to QGIS to overlay the data on my map?
4
votes
1answer
37 views
QGIS-3 does not recognize “-3.40282e+38” float raster values as NoData
I have DEMs with "-3.40282e+38" values that are supposed to be the NoData values. However, if the rasters are loaded into QGIS (3.4.11), the value can not get assigned with "add additional no data ...
2
votes
1answer
70 views
Change Output name in Script - QGIS 3
I exported a model as script using the properly option in QGIS 3.8.
The Script works perfectly, but the output name is changed.
Heres a print of the model:
I want that the script´s output name, from ...
