Questions tagged [qgis]

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

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Creating polygon from DEM raster extent to merge overlapping polygons

I have two elevation rasters split along the Alaska- Canada border. https://drive.google.com/file/d/174BiQU35RascL7YX58MopJ3vJE0oRXDA/view?usp=sharing I need to merge them into one product but there ...
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Tools in QGIS for cleaning polyline topology?

Are there polyline topology cleaning tools in QGIS that perform same as ET Geowizard's "Renode Polylines" and "Clean Dangling Nodes" ? https://www.ian-ko.com/ET_GeoWizards/...
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Creating raster from centroids of another raster using QGIS/GDAL

I have a raster that is input into a model which generates outputs in a CSV format (Lon, Lat, Z value). The Lon and Lat are the centroids of the original raster's pixels. I want to use these centroids ...
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QGIS - I have two separate attribute tables, how I combine the two?

I have two separate attribute tables, one contains information about fire and the other contains the size of the forest that fire is in. The Fire IDs are different as they are data from different ...
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QGIS - I have a layer where I highlighted the place of interest, Another layer contains all the data of the whole globe, How do I combine the data [closed]

I have a shapefile where it highlights Indonesia and contains attributes of its Forest Fragment sizes in there. I have another shapefile where it contains attributes of the fires of the whole globe. ...
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Windows QGIS Server Error 403

So I'm trying to set up a QGIS server on Windows 10. I followed the following instruction: QGIS Documentation The apache server is running but step 2.2.5 didn't work: http://localhost:8080/cgi-bin/...
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How do you change Map scale interactively in Print Map Composer?

In QGIS's Layout window there are several zoom icons a Move Item Content tool. Is there a Zoom Item Content tool or mechanism? Or must one set the Map Item Scale explicitly in the Main Properties ...
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Make precipitation map in QGIS or ArcGIS or in Python [closed]

My study area is belong to NE India. Some part of my study area is even in Tibet. I want to know how to download open precipitation data and make a precipitation map study area. I have tried using ...
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1 answer
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How to stack layers (slope, curvature, aspect, etc) derived from DEM to form multi-band images in QGIS?

Made a DEM from Landsat imagery and derived the aspect, slope, curvature, TWI, etc layers (generic flood conditioning factors). I now need to incorporate these layers and feed them to a LSTM neural ...
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Calculate accuracy between a raster data and shapefile data

I have two datasets: Shapefile (Ground truth): containing polygons where there was a rain Raster data (Model prediction): containing three values [0,1] where 0 indicates no rain predicted, 1 rain ...
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No module name qgis in QGIS 3.22

I recently upgraded to QGIS 3.22 For plugin development I am using PyCharm. after upgrading QGIS to this version PyCharm is not able to read the pyqt, QGIS modules. I am running PyCharm with the ...
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Splitting polygons while keeping the same entry in attribute table

I have a map of several agricultural fields with unique data for each field. I want to run some calculations per cultivated area based on the polygon layer. Some fields have roads running through them ...
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Open ArcGIS Map Service tile layer in QGIS

I am trying to open this tile layer (https://www.arcgis.com/home/item.html?id=aa6ba39647df4bd4a58e3e06c8386b30) in QGIS. I know it is possible to connect to ArcGIS Map Service layers but when I use ...
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Error when running Import Geotagged Photos in QGIS

QGIS version 3.26.1-Buenos Aires on macOS 12.5, Monterey Following this tutorial Processing Toolbar panel >> Vector Creation >> Double click on Import Geotagged Photos. Error: 2022-07-...
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Work (see) in the workspace with the exact elements in a print layout in QGIS 3

Is there any possibility to see (to work with) exactly what you get in a print layout in QGIS 3? I have an A3 layout, at 1:45000 scale, but i cannot arrange all elements because I get a different ...
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2 votes
2 answers
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Determining intersection of spatial lines with county polygons using QGIS

I have one shapefile that is railroad lines (in red) and another that is a shapefile of US county boundaries in 1890 and I would like to figure out which counties have railroads versus counties that ...
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Fields with both numbers and letters don't join in QGIS [closed]

I have a bizarre problem with QGIS. I'm trying to join a .csv file with a shapefile, and the join field is a precinct code. Some precinct codes in my .csv are purely numbers, but some have a letter ...
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1 vote
1 answer
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How to draw a polygon of all points in a certain height range

At the moment I have a raster file of elevations, and I am interested in creating a polygon that consists of all points whose heights are between x and y. So its boundaries will be the union of the x ...
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2 votes
1 answer
39 views

Removing extreme values from a (calculated) raster in QGIS

I have a Landsat GeoTIFF with a multiplicative scaling factor of 0.01. When I load the tif into QGIS and multiply the raster by 0.01 extreme values are created (see attached picture). Looking at the ...
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0 votes
1 answer
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Updating a large PostgreSQL table using QGIS [closed]

I have a large table on a (non-spatial) PostgreSQL database which I had created using QGIS to upload the (geometryless) attribute data from a point layer. The database is merely used for data analysis ...
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1 answer
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How to isolate overlapping polygons in the same layer with SQL

I have one layer with hundreds of polygons and I would like to attain a list of overlapping feature_ids. I read that I need to join the table to itself but I don't understand how that helps. This is ...
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3 votes
2 answers
49 views

How can I add a specified, global number of points randomly across polygons in QGIS?

When I go to Vector > Research Tools > Random Points in Polygons in QGIS, I can specify a specific number of points I can add randomly into each feature (each polygon for me). So if I have 15 ...
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Having qgis2web display info in popup for overlapping layers or overlapping features in layer

This is my first venture into webmaps. I have a project that I am trying to export with qgis2web Leaflet option. I have a layer with overlapping polygons, and I would like for the info popup to ...
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2 votes
0 answers
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Adding several attachments in one polygon attribute field using QGIS

I need to add several files (for instance JPEG, DWG, PNG, etc.) as attachments in one polygon attribute field. For that, I created a new field with widget Type - Attachment. But it allows adding only ...
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15 views

Some labels disappear when exported from QGIS to DXF

I'm using QGIS 3.14. I have two layers with labels in Qgis, set up to Map units. In "rendering" section of label properties I have set up to show all labels for these layers. I want to ...
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1 vote
1 answer
28 views

Using combine function in QGIS modeler

I am trying to use the QGIS modeler with the 'combine' function, but when I run the model, it only gives me one choice of shapefile to choose instead of letting me choose more than one raster to ...
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4 votes
3 answers
112 views

Accessing Spanish cadastral data via QGIS

Problem I would like to have access to cadastral data (= land parcels) of Spain in vector format, so I can do further processing on them and put them into a database. I tried to do this multiple ways, ...
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0 answers
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Error digitizing map in QGIS 3.22.7 Bialowieza

I was following a tutorial to learn digitizing maps from raster images and the following error occurs while executing the digitizing command while using QGIS 3.22.7 on a Windows 10 machine. Also one ...
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2 votes
1 answer
47 views

QGIS Map Composer frame to show numbers and letters [duplicate]

I'm trying to create a tactical burn plan map using QGIS. 3.10.3. It needs to be able to be used by lay people to communicate where features are on the map. To do so I need the map frame to show ...
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1 answer
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How to identify the closest point in a single layer?

I am new to GIS. I have multiple coordinates of places from Safegraph. I believe there are some duplicates in my file (they have different IDs, but they seem to be identical places based on their ...
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2 votes
0 answers
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Using layers with different CRS in Intersection tool of QGIS

I've always thought that to intersect two layers, they needed to have the same CRS. Today, I tested the Intersection tool to intersect layers with different CRSs, and I was surprised to see that it ...
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1 vote
0 answers
29 views

Understanding Mean +/- 1.5 SD in QGIS Symbology [closed]

I'm trying to automate a process that is now being made in QGIS, but I'd like to "transfer" the same operations to an R (or other language) code. What I have is NDVI images for a given ...
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QGIS changes vector color when exporting to pdf

I'm printing a contour map I made, and I've made some of the lines blue (10m) and some of the lines black (50m). The map looks correct in the layout, but as soon as I export to pdf, the blue lines ...
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5 votes
1 answer
74 views

Create biggest possible rectangular polygon from grids in QGIS

I am working in QGIS (Modeler with some Python scripting) and I have troubles performing the following task: I have the following grid: I have to create the biggest possible rectangle polygon out of ...
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4 votes
1 answer
48 views

Synchronize QGIS layout map scale with canvas scale

Is there any option to make the map scale match the canvas scale automatically? That is without having to use the "Set map scale to match main canvas scale" button. Actually I expected it to ...
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2 votes
1 answer
45 views

How to split line with trace by specific length in QGIS

I'm modifying the existing water pipeline network. Sometimes I have information that the pipe from the beginning to the 125meter has a diameter 63mm after that point it has a 100meter -diameter 50mm ...
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0 votes
0 answers
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Merge Landsat GeoTIFF files failed in QGIS

I am working with Landsat-9 images, I want to merge two GeoTIFF files of same band. These are the images I want to merge. I set the following raster -> miscellaneous->merge. I set assign '0' as ...
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1 vote
1 answer
21 views

Convert points with x,y coords and value from to a raster image

I have a CSV file with xcoord,ycoord and pixel value from DEM. After I import it in QGIS, I take this table. I want to make a raster from this point layer. I tried rasterized (vector to raster), I ...
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0 votes
0 answers
12 views

QGIS merging asc files then importing to Iberaula doesn't appear

I'm trying to merge multiple asc files together, when I merged them all, and export it to a merged asc file. When importing this to Iberaula, nothing appears to show. Does anyone know why?
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1 vote
1 answer
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How can I know the length of a line with different weight depending on a raster?

How can I know the length of a line with different weight depending on a raster? I have a line that crosses some areas with different environmental weight. The values of the different areas in the ...
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0 answers
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IBERAULA - DEM file not working

When using Iberaula, I'm trying to use the data from Defra or OS Terrain 50 as this is UK data. However, I'm trying to import the DEM data through RTIN > Create RTIN > Mesh and import the DTM ...
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3 votes
0 answers
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How to remove noise from a DSM (city center) to create a 3D printable model

For the company I work for, I need to create a 3D printable model of a part of a city's downtown area. At my disposal (upon request to local government authorities) I have point clouds from LiDAR ...
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1 vote
1 answer
40 views

Colours in GeoTIFFs

Coming from a somewhat "Photoshop" background, I am having trouble understanding how colouring/visualization works in QGIS. When I import a GeoTIFF I get min and max clip values in the 3 ...
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0 votes
2 answers
33 views

Change attribute table appearance to show only features visible in map

Working with big WFS it can take forever to open the tables. Is it possible to choose to show only features visible in map before opening it?
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0 answers
33 views

Rule Based Symbology

I am using QGIS 3.16 version. I used this expression $id=@atlas_featureid for my inside features and $id!=@atlas_featureid for my outside features filter in rule based symbology and my layers ...
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0 answers
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Clip error while saving to KML

I'm using QGIS 3.22 I'm trying to use Clip to a shape file of eligible forest area and input and overlay is a region, e.g. Triloca. When I clip and save as Temporary layer OR a Shapefile then the clip ...
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0 answers
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Browser-based layer editing

Does anyone know of a software that is similar in function to this Esri example: https://developers.arcgis.com/javascript/latest/sample-code/draw-line/ But relies on other technologies apart from Esri?...
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No Raster Georeferencer in PLugin List QGIS 3.26.1-Buenos Aires [duplicate]

I have QGIS 3.26.1-Buenos Aires The Raster Georeferncer is not located under "Raster" Nor does it appear when I search for "Georeferencer" in the "Manage and Install Plugins&...
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4 votes
1 answer
37 views

Filter array with a field value

I need to filter filenames (like DJI_0147_3_5.jpg) in an array, and the code below works, but, where you see a 3 in regex, I need instead a field value. In the array output (sourcefile field) we have ...
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0 votes
0 answers
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Save Error trying to export "POINT" Vector Layer as it is being identified as a LINESTRING

Trying to export/make permanent "Unique Stream ID" scratch vector layer output by the r.stream.extract tool apart of the GRASS 7 v2.0 toolkit produces an error stating that the file is a ...
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