Questions tagged [qgis-3]
for questions specific to the 3.x series of QGIS.
2,072
questions
0
votes
0answers
4 views
PyQGIS grass7:v.distance parameter error “The number of columns and the number of upload parameters should be equal!”
I am currently working on a Python script for QGIS in which I would like to obtain the (minimum) distance from each point (polygon centroid) in the points layer centroid_layer to the line layer ...
0
votes
0answers
5 views
QGIS 3.10 fails to install plugin (Waternetanalyzer) from repository
I wrote a plugin which is installed properly in QGIS 3.4, ... QGIS 3.9. But it cannot be installed from the repository in QGIS 3.10. An error occurs (see picture below) and no tools are added to the ...
0
votes
1answer
13 views
Refresh Oracle Layer with PyQgis
I'm working on a Dockwidget with PyQgis.
I made an insert into an Oracle DB and I would like to see the new insert (it's a point).
The Layer where the new point is add is URB_A_ADPT. I'm sure the ...
1
vote
1answer
35 views
Dynamic decoration QGIS3
I try to make «copyright» decoration in QGIS dynamic.
I have a surface layer «COMMUNE» with a "NAME" field.
I try to write an expression that allows me to display this "NAME" in the decoration, I ...
1
vote
0answers
19 views
Extending QGIS wordwrap function
I've got an idea that I'd like to try in order to extend the QGIS 3 "wordwrap" label engine function. Ultimately, I'd like to enable users to set min and max length for a single line, and then wrap ...
0
votes
1answer
27 views
A loop to select all active layers in a project [duplicate]
I am trying to export all active layers in a QGIS project to a specified folder, below is what I get atm
Outputdir='C:/Users/DN/Downloads/Test/'
layer = iface.activeLayer()
QgsVectorFileWriter....
0
votes
0answers
31 views
Creating a Heatmap of Delivery Probability in QGIS3
Im using QGIS 3.4.2 to create a heatmap to plot the source place where a network message is generated, in a vehicular network.
I separated the messages in two groups, one in each layer: delivered and ...
0
votes
0answers
16 views
Insert/append list values to a layer using QGIS Python [on hold]
I have created a list in the format of a layer. I need to insert/append the values of list in to the layer as new row/data. Also this data has no geometry. How can I do this?
1
vote
1answer
48 views
Calling the correct element of an output via PyQGIS Script
I am trying to apply a style to the output file of a script that I´m running from the toolbox in QGIS 3.4.7. The last step is as described below.
def processAlgorithm(self, parameters, ...
3
votes
1answer
68 views
QGIS: create lines to connect points which are within a distance to each other
I have a point layer and I'm Looking for a tool wich connects every point of the layer with each other. Ideally, I can give a distance and the number of Connections for each point. The following ...
2
votes
2answers
51 views
Adding own items into QGIS 3.10 news feed?
Is there a possibility of adding own items into the news feed of QGIS 3.10? As a GIS administrator it would be a great tool to spread GIS/QGIS related news to internal colleagues.
3
votes
0answers
28 views
Find distance between multiple discrete sets of points QGIS3.8
No similar question seems to relate to my issue but I desperately need help with calculating distances.
I have a CSV with the residential postcode of 200 000 patients. For each patient, I also have ...
2
votes
0answers
22 views
How to change a widget type of a field by using python
I'm working on a plugin for QGIS 3.x and I'm looking for an example how I can change the widget type by using Python code. The change should be applied on fields of a vector layer.
At the end it ...
0
votes
0answers
12 views
Garmin/Navionic charts in QGIS
I'm looking for an option to import nautical maps (mostly for depth data) into QGIS. So far, I managed to import NOAA .KAP files, but coverage and resolution of some areas are not very good. Is there ...
1
vote
1answer
35 views
How to homogenize NA values within a .gpkg from R
I have created an SpatialPointsDataFrame in R with some data.
Here is the outputs from R:
> class(Fotos)
[1] "SpatialPointsDataFrame"
attr(,"package")
[1] "sp"
> class(Fotos$Azimuth)
[1] "...
2
votes
0answers
18 views
Change the colors of the pie chart in compouse (plot) in QGIS 3.10
When using the new plot command available in QGIS 3.10 for compouse pie chart generation, I didn't find any option to change colors.
Is there any way to choose colors?
1
vote
1answer
26 views
Qgis 3 : QgsEditorWidgetSetup for date
I need to make a date format in QGIS 3 but, in the program I need to use,
QgsEditorWidgetSetup('Date',{'yyyymmdd'}), I want to get this:
But I don't know how to use QgsEditorWidgetSetup to make the ...
1
vote
0answers
15 views
Which type of slash to use in path - QGIS 3.8 with Python [on hold]
I'm a beginner using Python. I had a problem loading a shapefile in QGIS 3.8 using Python, while loading a rasterfile worked perfectly.
I found the solution here: Can't load a shapefile with ...
1
vote
0answers
37 views
Balancing multiple supply and demand locations in QGIS
I am looking for a way to balance supply and demand with respect to distance, between two vector layers in QGIS.
I have two vector layers 50x50m grid
Supply (The red negative values)
Demand (The ...
1
vote
0answers
24 views
What is happening with the centroids that are not on the road layer when you use the Shortest path (layer to point) from Network Analysis?
I am using QGIS 3.8.1 and I want to compute the shortest path of the centroids of any commune to Paris using the roman network. The centroids are the yellow points the road net is the green lines. ...
3
votes
1answer
36 views
QGIS: Creating custom CRS without using the GUI
What would be the appropriate way to create a custom CRS without using the GUI of QGIS on Windows?
I am trying to create a custom CRS but my GUI seems to be broken. I cannot use the normal way ("...
1
vote
0answers
15 views
QGIS 3.4.5 print composer: doesn't print DIN A0
I want to find a way to print a map with a raster layer in greyscale (GeoTIFF) and two vector layers in shp-format.
I created a map layout and went to the page properties (right-click on the canvas) ...
1
vote
0answers
31 views
PYQGIS QgsAction Does Not Work
I am using QGIS3.4 (built-in Python 3) actions.addAction and trying to open a local photo, with the below code I am able to store the photo path in the feature attribute and created an action, I have ...
1
vote
0answers
15 views
Starting QGIS 3.4 with own startup.py faults on Mac OSX Catalina
Created file startup.py:
from qgis.core import *
QgsApplication.setPrefixPath('/Applications/QGIS3.app/Contents/MacOS', True)
qgs = QgsApplication([], False)
qgs.initQgis()
qgs.exitQgis()
and saved ...
0
votes
0answers
20 views
Open QGIS Project in both Linux/Windows
My company has workers that use Windows and Linux to manage a QGIS project. However, when we use the same project created in different operate systems the layers lose file paths.
Is there ...
1
vote
1answer
16 views
Write layer style .qml as predefined within a gpkg using R
I have this code to export a layer (Pbm) to a gpkg called "Atlas":
writeOGR(Pbm, paste0(normalizePath(OutputFolder),'\\', "Atlas.gpkg"),"Atlas",
driver="GPKG", encoding = "UTF-8", ...
1
vote
0answers
9 views
Sorting Relation_Aggregation Expression Results in QGIS3
I am using a relation aggregation expression to grab a list of inflows from other sewersheds. Some sewersheds take on flows from more sewersheds than others so I approached it through a relation so ...
0
votes
0answers
19 views
Why does measurement units return degrees when using PyQgis? [duplicate]
I am using PyQgis to measure some selected line features using distance.measureLength(feature.geometry()) and when I use distance.lengthUnits() I get returned a value of 6 which refers to degrees. My ...
1
vote
1answer
27 views
Clip raster by mask layer change the pixels size
I've a raster that have the pixels of this dimensions:
x 0.2282548198093489467 m
y 0.3594572165075641257 m
I need to clip this raster with a vector because I need a raster with the same extensions ...
2
votes
0answers
16 views
Outputting layer as table at end of process
I am in the process of migrating some QGIS 2.x processing toolbox script to QGIS 3.x.
I have a collection of scripts that helps in the seismic 3D planning and geometry processing.
One of the scripts ...
2
votes
0answers
30 views
QGIS 3.4 - Can't Save Custom Projection [duplicate]
I am having the same issue on QGIS 3.10 or the long term release, 3.4
If I go to Settings > Custom Projection and add a name and parameters, the "OK" button does nothing.
I have tried clicking the ...
1
vote
1answer
34 views
QGIS 3.4.12 print composer, cm distance
In print composer, I would like to syncronize the scale of the map with the Grid scale. For example, in print composer I am making a map in 1/1000 scale, so I go to grid,and insert "map units" x=100 y=...
1
vote
1answer
35 views
Why the “shape tools” won't work with a different CRS?
I just used a tool from the "Shape Tools" plugin but the results were nonsense. The CRS of the point layer and my project CRS were EPSG:4326 - WGS 84.
Here is an image of the result: The correct ...
1
vote
1answer
59 views
Creating custom CRS in QGIS
I am trying to define a custom CRS in QGIS 3.4 to work on some data in Central Asia. I want to use the Albers Equal Area Conic but change the parameters so that the transformation works best for my ...
2
votes
0answers
22 views
Search yields no results in plugins menu
I can't manage to figure out why I can't download any plugins. I have an Internet connection, but it seems like QGIS can't access the online repository of plugins.
As an example, I'd like to download ...
1
vote
0answers
19 views
QGIS Graticule at Print Layout starting at from 0
I would like to add a graticule with coordinates to my map. However, when I add a new grid and modify it the graticule appears but it always starts at 0 and not from its real value.
How could I fix ...
2
votes
1answer
16 views
Unable to set scale on QgsLayoutItemMap
I have made manually one layout in QGIS 3.10, I access it using PyQGIS and I want to add a new QgsLayoutItemMap. I'm unable to set scale correctly. Does I miss a step? Is it a bug? Are you able to ...
2
votes
0answers
10 views
Sharing classes and methods code among processing scripts
I am writing a set of processing scripts for seismic data acquisition (2D and 3D) planning and geometry processing. They are very crude scripts (I'm not a developer) that performs the tasks I meant ...
2
votes
1answer
50 views
How to display the correct unit of measure in PyQgis?
Within a plugin I am developing I select features and for each line feature selected I get the feature distance using:
distance.measureLength(feature.geometry())
I also get the total length at the ...
1
vote
0answers
38 views
How to retrieve text from a QLineEdit in a tabifyDockWidget
I've write a plugin that calls a tool when a certain push button in my tabifyDockWidget is clicked. When the comboBox button is clicked it works perfectly carring the comboBox.currentText() to the ...
2
votes
1answer
42 views
Why does QGIS convert IntegerLists into something strange and how do I process these in PyQGIS?
I have GeoJSON data which has an integer list and I'd like to query that list in QGIS via GUI (select by expression, visualization) and probably later with PyQGIS.
The problem is that QGIS recognizes ...
3
votes
3answers
193 views
PyQGIS using selected layer from a combobox
With PyQGIS 3, I defined a comboBox to list layers from a QGIS project. I want to use the selected one to execute a treatment. I tried comboBox.currentData() class but it doesn't seem to be the good ...
1
vote
0answers
27 views
Rotating vector grid in QGIS 3.10 vs 3.8
Just wondering if anyone else has had an issue with vector rotation via the advanced editing tools in 3.10?
I have a vertical grid overlaying Vancouver Island that I had tried to rotate using the ...
4
votes
2answers
76 views
Making curved stroke shape of polygon
I have a lot of polygons representing Forest land use type. Is it possible to style these polygons in such a way like on this picture?
Example polygon I have now:
So the polygon doesn't have edges, ...
2
votes
1answer
35 views
Setting label colour based on a field value?
I have created a shapefile with lines which I use to place labels exactly where I want them relative to map features. The shapefile has a field for the name that will appear as the label and also a ...
2
votes
1answer
22 views
pyqgis create layer from a list of points
I am working with pyqgis in QGIS3 and i want to create a point layer from an intersection beetween a point and a polygon layer. I can identify wich points intersects my polygon layer but i can't use ...
1
vote
0answers
14 views
Add python modules so scriptrunner will find them for QGIS on Mac
I am using QGIS 3.10, and Mac OS 10.(14 & 15)
This issue relates to recent versions of QGIS for the Mac that are distributed as .dmg.
These versions of QGIS bundle their chosen version of Python ...
4
votes
1answer
74 views
Processing toolbox not working in QGIS 3.4.13
The processing toolbox stopped working in the previous QGIS 3 ltr version I had installed. Now installed 3.4.13 but processing toolbox still not working. I've tried changing the GRASS path without ...
4
votes
1answer
47 views
How to edit a processing tool in QGIS
Is it possible to make a copy of a tool from the Processing Toolbox in QGIS and make edits to it?
As an example, I would like to make a copy of the Import geotagged photos tool and then edit the code ...
1
vote
0answers
48 views
Linear extrapolation of points using QGIS
I am currently working with hurricane data from NOAA’s IBTrACS. Each gathered data point is separated by three hours. The points and lines can be found in two different data sets on the IBTrACS ...
