Questions tagged [qgis]

QGIS is a cross-platform GIS application licensed under the GNU General Public License.

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1answer
38 views

Acessing fields of created features in your PyQGIS

I'm new using PyQGIS 3 and I'm wondering how to access the field information from a layer generated by script. inside my processAlgorithm function I have the following: alg_params = { '...
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2answers
9k views

Is it possible to convert Polygon to centerline linestring?

I have a Polygon which I want to convert to centerline linestring. IMAGE 1 I used the Vector to convert to Polyline but they are not center line as under: VECTOR TOOL IMAGE 2 Polyline created by ...
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0answers
30 views

Fixing problem with processing component

How can I fix the problem with the processing component? Since it appears to me that it is broken and I need to activate some functions of the Raster option. When I want to activate the processing ...
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0answers
19 views

TypeError : can't concat str to bytes

I'm actually using QGIS (3.10 a Coruña) on Mac OS Catalina and I'm having troubles with it. I'd like to use the function "r.reclass" but it doesn't run correctly. It says that there is an ...
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0answers
19 views

I cannot click any icons or features in the QGIS software [closed]

So I'm creating a simple map using QGIS for the first time, but I can no longer click anything, not even minimize or close the app.
4
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1answer
69 views

Using conditions in Graphical modeler QGIS 3.10.5

I have a question about my model which is quite complex. I have two types of line INPUT and the model will not be executed unless one of the line INPUT is empty. The problem is with a tool 'Snap ...
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0answers
18 views

QGIS statistical summary gives exponential value

I need the precise sum of areas for a polygon layer, where I have the area values in an attribute. When I use the Statistical Summary window it shows the sum in exponential notation: Statistic Value ...
5
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1answer
126 views

Finding the sequence/rank of lines (polylines) in QGIS

I have line shapefile with different bus routes (each route consist of multiple line), in which I want to sequentially arrange the lines for each bus route based on the direction of route. I tried ...
4
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1answer
56 views

Placing point over pixel with maximum value falling in grid overlay using QGIS

I have a raster layer with a Shapefile grid with cells measuring 3 x 3 m overlaid on top. All I want to do is find the pixel with the maximum value within each cell, and place a Shapefile point over ...
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0answers
27 views

How can I solve the problem with the processing component? [duplicate]

How can I fix "The processing component is broken" problem?
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0answers
37 views

Putting a point over pixels with highest DN values within grids in QGIS [duplicate]

I have a raster layer in greyscale, and a vector layer that is 3 x 3 m grid. One of the attributes within the grid cell layer is the value of the highest DN number within that grid cell. I just need ...
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1answer
49 views

Missing / misnamed fields in PostgreSQL table join in QGIS

First, I'm brand new to PostgreSQL and PostGIS, so my question is probably asked wrong, and it may be a duplicate – but my search attempts didn't find anything. Also, I don't expect this is an issue ...
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0answers
39 views

Problem exporting shp as CSV

I imported a shapefile into QGIS, made a copy of it, and edited that copy. My edits consisted in changes in the coordinates of a few points. I then exported this edited shapefile as a .csv. For peace ...
2
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1answer
45 views

Visualize polyline n-to-n relations in QGIS using PyQGIS

I have 2 traffic networks (A and B) with links relating to each other. Each link has an id. E.g. link 1 of network A can have a relation to 3 links of network B. Link 2 of network A might also have a ...
3
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1answer
340 views

Easy Custom Labelling Error Code

I'm getting the following error - only on one of the vectory layers in my project. Can anyone help? Have tried a restart and reloading the layer and neither worked! An error has occured while ...
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0answers
23 views

QGIS animation help ancestral records

I only have basic GIS skills and wanted some advice or direction. I'm only practicing with a smaller dataset at the moment though my other files are much larger 10,000+ so don't know if it's possible ...
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1answer
37 views

How to draw centerlines of Oriented Minimum Bounding Box in the orientation closest to orientation of all polygons collectively in QGIS?

How to draw centerlines of Oriented Minimum Bounding Box in the orientation closest to overall orientation of all polygons collectively in the layer in QGIS? I have a shapefile of Oriented Minimum ...
5
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2answers
67 views

QNEAT3: Iso-Area as polygons problem

I am using the QNEAT plugin to calculate catchment are/travel reach over a street network. The network is valid and projected correctly. I have tried changing the cell size and topology tolerance ...
1
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1answer
43 views

How to Share a QGIS Project

I want to share my QGIS project to someone else who also uses QGIS, how would I do this? I am very new to QGIS and am not very tech savvy.
4
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3answers
322 views

Reordering layers in GeoPackage and changing the default naming in QGIS?

I have successfully saved several layers in one GeoPackage in QGIS 3.8. This is how it looks like in DB manager: I found out that the ordering of the layers is somehow strange when loading the GPKG ...
12
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4answers
4k views

Making QGIS attribute table field automatic?

I'm working in a way to make hydrologic projects using QGIS and an Excel worksheet that I have. To do this, I want to extract some information of the lines, included in a vector layer, which ...
4
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1answer
34 views

Creating custom categorized symbology and coloring based on two fieldNames

I am developing a plugin in PyQGIS 3. Within this plugin, I want to change the symbology of a layer to categorized. I want to categorize based on the column Collecti_2 in PyQGIS 3. This step has been ...
4
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1answer
82 views

Calculating dominant angle of a polygon in QGIS without main_angle function

How can I calculate dominant angle of a polygon in QGIS without main_angle function? I have a shapefile of Oriented Minimum Bounding Box rectangles (accessible from the following link: https://drive....
3
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1answer
29 views

Creating polygons with “Create shapefile layer” always produce multipolygons instead of polygons when saving in QGIS

Not sure if is a bug or I'm missing something. Every time i'm creating a new shapefile with "Create shapefile layer" i got a multipolygon instead of a polygon (at least is what I'm expecting)...
3
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2answers
61 views

Get folder path to QGIS processing scripts from PyQGIS

Where is stored path to processing scripts folder in PyQGIS? Version of QGIS is 3.16. I want to get this path by Python script. I suppose then, is stored in processing object: from qgis import ...
6
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1answer
42 views

Saving two shapefiles into one GeoJSON

I have 2 shapefiles in QGIS (one point layer and one Line layer as shown in Figure). I am trying to save these two layers in one GeoJSON. I have seen some of the previous answers such as answer [1] , ...
9
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1answer
86 views

Categorising point layer twice by size and form in QGIS

I have data points from a CSV-file that I opened in QGIS. The points illustrate different power plants of solar, wind, geothermal, coal, oil, etc with different capacities within each class. I already ...
3
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3answers
1k views

import qgis.core, dll not Found

in the 'System Variables' i set Path =C:\OSGeo4W64\apps\qgis\bin This is where the 'qgis_core.dll' is located. PYTHONPATH=C:\OSGeo4W64\apps\qgis\python But when i import qgis.core i get: run ...
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0answers
28 views

How do I solve the problem of the processing plugin, because it marks it as broken? [duplicate]

I am new to using the QGIS program. I have a problem that I hope you can help me. The processing component tells me that it is broken and therefore does not let me activate a different options that ...
0
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0answers
34 views

Adding point features by machine learning in QGIS 3.16

I've got several georeferenced traditional maps and there are circles on it. (these are the studied points) So I want to add point features to the middle of the circles. I could do it manually, but I ...
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0answers
20 views

QGIS binaries download servers are down? [closed]

The QGIS binaries download servers are down? I'm trying to download both 3.10 and 3.16 versions for Windows and Mac from two machines, and the download stuck everytime: 3.16: https://qgis.org/...
4
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1answer
38 views

Make QGIS use a conda virtual environment for python libraries

I wanted to install a plugin, but it requires scipy. Thus I realized that QGIS use the default python3 installation. I tried to launch it from a conda virtual environment, as advised in this related ...
0
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2answers
37 views

Splitting two large TIFs covering the same area (or very similar areas) into smaller chips

I downloaded a bunch of images from Maxar's Open Data program covering pre- and post-images of recent disasters. See https://www.maxar.com/open-data The pre-event and post-event images cover the same (...
3
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1answer
72 views

Making vector geometries “Kiss” in QGIS

I am working with vector geometries that I recently simplified using the native:simplifygeometries method in the processing toolbox. I am pleased with the simplification but I want to "fill" ...
0
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0answers
32 views

QGIS Desktop 3.10.6 works fine when I use my laptop at the office but stops responding when using it at home

I'm stumped on why my QGIS performance is terrible when working from home but fine in the office. I am not using a vpn, all the files being used are on local hard drive, internet works fine at home, ...
0
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0answers
20 views

QGIS style changing

I want choose a properties of a layer and change it's style in QGIS (I have an extension for nautical symbols), but before loading files it's restricted. What I want to load is a huge amount of ...
0
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1answer
29 views

Completion in input form works on QGIS but not on QField

I created an attribute form for a shapefile layer. For one of the fields ("NAME") that I want to fill in, I have opted for an entry by relational value. I selected "the layer", the ...
0
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1answer
103 views

How can I stack several 3D elevation layers?

So far I have been using qgis2threejs to display different layers at once like one terrain elevation layer and one population data layer. The result through is that the 3D population data is not ...
1
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3answers
48 views

QGIS SpatiaLite layer does not display

I am having a problem in QGIS with some layers failing to display on the map canvas. I am trying to learn about QGIS by working through the Training Manual found on docs.qgis.org. I am running version ...
0
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1answer
23 views

Extract data from one shapefile based on another [closed]

I am using QGIS 3.16.1. I'm trying to find a way to have it tell me what the most common soil type is in a field boundary. I have downloaded the soil information from NRCS's web soil survey site and ...
2
votes
1answer
37 views

QGIS 3.10.13 (64-bit) on a Asus laptop with Windows 10 is running EXTREMELY SLOW - looking for suggestions

I am using: QGIS 3.10.13 (64 Bit) My machine: OS: Windows 10 Home, version 20H2, OS build 19042.746 Installed RAM: 12.0 GB ( 11.9 GB usable) Processor: Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz, 2201 ...
0
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0answers
33 views

How does a shape fits into a polygon? [closed]

Is there a QGIS Plugin (or ArcMap tool) or a PostGIS tool where I can see if a polygon fits into another polygon? For example I have a layer with a polygon A and then I have another layer with a much ...
0
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0answers
21 views

Mapping origins and destinations to the created isochrones

I created isochrones in QGIS with an interval of 30 minutes. I have some coordinates related to some origins and destinations as well as travel time from the origins to the destinations. I need to map ...
3
votes
2answers
322 views

QGIS taking too long to load/launch on Windows 10

I had a version installed, I think it was 3.4.10, and used it couple months back it worked great. I tried opening it yesterday and it took forever. I uninstalled it and installed the latest version 3....
0
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1answer
44 views

Getting Tkinter to work in PyCharm using OSGeo4W64's Python

I am creating an external QGIS program that builds virtual rasters using the processing algorithm within QGIS. I have this working, but it is not very convenient since you need to type in each file ...
1
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2answers
31 views

QGIS: Legend not displaying symbology of items

I'm making a plant including power plants in a country. I plotted the plants and their symbology shows up in properties in the legend items but it does not in the legend itself as you can see in the ...
1
vote
1answer
410 views

Creating multiple polygons within one geometry generator using QGIS?

Is it possible to create multiple geom_from_wkt() elements like Using QGIS Geometry Generator to get rectangle from point? in a single geometry generator symbol layer?
3
votes
1answer
34 views

How to do a “many-to-one” join

I have used the distance matrix tool for a large point set (100 000+ points) to find three closest POI's from another layer and their distances. The distance matrix outputs a table much like this: ...
3
votes
1answer
73 views

Mapping polygons into lines and projecting lines on road network

I have a layer with polygons that describe road damages. I have then another layer with road network lines. The layers are shown in the picture. I need to project the polygons as lines to the road ...
1
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0answers
22 views

Construction mode multiple points

Is there a way to define multiple points to snap in the construction mode in advanced digitizing? Let's suppose I want the value -26- from point 3 to 4 but also want a value -31- from point 1 to 4. ...

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