Questions tagged [qgis]

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

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4
votes
1answer
36 views

QGIS Processing modeler not showing toolbar

I've just installed QGIS recently (3.10.10 with GRASS 7.8.3) on a new computer. Previously, I used the same version and there's a toolbar in the Processing Modeler (to save and run model). But now, I ...
6
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1answer
76 views

QGIS custom function error when trying to get color of feature on another layer

In QGIS 3.16.2 (same on 3.16.0) on Win 10, I created a custom function get_color to get a feature's color by layer name\id and feature ID as proposed in this answer by @Dror Bogin: https://gis....
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2answers
41 views

Follow-up query on “QGIS expression for label text to display vertex coordinates of polygons”

Just a follow-up query about the existing thread QGIS expression for label text to display vertex coordinates of polygons. Is there an expression in QGIS to collect all the coordinates from the ...
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1answer
30 views

From several polygons of one layer to several layers/files

I'm new in QGIS and I have a question. I am sampling an onion crop from a geottif: I need to export each single rectangle/polygon into a single tiff file. Is there a plug-in for doing so?
5
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1answer
42 views

QGIS GeoPDF Export - change field that appears top in pdf model tree

I am exporting a map layout to GeoPDF using QGIS. Is there a way to change/choose the layer field that gets used in the pdf model tree as the display field for each record? I have attached a ...
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0answers
15 views

Installing QGIS 3 on Trisquel 8

I modified my repository like this: deb https://qgis.org/ubuntugis xenial main deb-src https://qgis.org/ubuntugis xenial main Then: sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable Finally: ...
2
votes
1answer
36 views

Importing special/custom csv files to QGIS

I'm trying to import a csv file. Most similar cases are trivial but the csv file contains only the data (sunshine hours) and a header specifying the coordinate of the first cell, the number of columns ...
3
votes
1answer
109 views

Imported CSV data is not displayed in QGIS

I watched a simple video tutorial on how to accomplish it, but nothing shows up on my project when I add the layer. Even if I try zoom to layer, the screen just shows blue. I'm not sure if it has ...
1
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0answers
39 views

Importing spreadsheet CSV file with coordinates into QGIS [duplicate]

I watched a simple video tutorial on how to accomplish it, but nothing shows up on my project when I add the layer. Even if I try zoom to layer, the screen just shows blue. I'm not sure if it has ...
4
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0answers
23 views

Batch create multiple buffers with variable size around point

For a statistical analysis, I need to calculate some landscape properties in several (rectangular) sample areas, which vary in size (extent ranging from 10 by 10 to 500 by 500). These sample areas are ...
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0answers
13 views

QGIS crashes loading raster layer (.tif) through GDAL provider

I am working on a project that uses QGIS within another application using QT Creator. When I try loading my raster data (using C++ API), I get a SIGSEGV error that traces back to my GDAL provider ...
5
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1answer
105 views

Making a buffer cover a specific area (need to calculate overlap)

I work in precision agriculture and use QGIS. Today's technology makes it possible to adjust the spreading width of, for example, sprayers and manure spreaders according to where you have driven ...
4
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2answers
101 views

Renaming multiple layers in the legend from an attribute in each layer in QGIS

I have 72 layers that have been generated via affine transform of a single layer that has 72 categories. But the 72 layers have been given names that are sequential numeric. The original categories ...
1
vote
1answer
45 views

QGIS - Join polygon layer attributes to line segments

I've got a hexagon layer with data that I want to have joined to the available road network for the area so that the road segments have the attributes from the hexagon layer. Each segment of the road ...
3
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0answers
31 views

QGIS 3.10 crashes constantly when performing join with virtual layer

I want to create a pie-chart map showing the amount of groundwater extracted from different aquifers within different administrative areas like in the picture below: I have a shapefile with ...
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0answers
20 views

Cut raster with mask [duplicate]

I have to cut a raster with a mask. However the mask is a raster. It's possible to do it? I using QGIS 3.10, with ESPG: 4326
5
votes
1answer
32 views

Using Set Z Value in QGIS Graphical Modeler - Modeler not passing elevations from field

I am trying to use the Set Z Value algorithm in QGIS Graphical Modeler. More specifically, I would like to set the elevations using values contained in a field in the input layer, but the elevations ...
3
votes
0answers
29 views

Align arrow (point layer) to water direction (line feature)

Assuming that pipes are digitizet correctly (first node as upstream, last as downstream), I need to align the arrows of a point layer to display flowmeter's direction. So far I need to use v.split (...
1
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0answers
31 views

Georeferencing Moon photos and LRO DEM but how to model the curvature of the Moon?

I tried to search for solution to this, but I could not find it. However, if this matter has been dealt somewhere here, please forward me to a correct thread. To summarize: I am using QGIS and ...
2
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3answers
87 views

Decreasing resolution of binary raster layer, but retain specific data using QGIS

In QGIS 3.16.2, I have a binary raster layer in which I would like to decrease map resolution without losing any value = 1 pixels (white in the example). I have tried exporting and changing the pixel ...
1
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0answers
23 views

QGIS Temporal support for WMS source showing latest image only

I'm trying to incorporate the sentinel definitive surface reflectance imagery into my project as sourced from the Digital Earth Australia OWS server (https://ows.dea.gov.au). I'd like to be able to ...
0
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0answers
23 views

Cutting a raster file utilising a vector polyline

I’m on 3.16 QGIS GRASS... It hasn’t got gdalwarp. Simple issue, I have a raster file which includes two regions: land and sea. I have a vector polyline that marks the division between land and sea. I ...
1
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0answers
18 views

Can't upload raster file on PostGIS

I've been trying to upload my satellite imagery which is 1.5 GB to my PostgreSQL database, using the code below, the error for each command is stated below; raster2pgsql -s 4326 -t auto -F -I -C -Y '....
2
votes
1answer
20 views

Selecting a feature using expression if attribute field is “NULL” [duplicate]

I am new to QGIS and am having, what I expect to be, an easy issue. I am working with a multi-polygon shapefile of taxable property parcels in QGIS 3.16. All it is I am trying to do is select all ...
3
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0answers
31 views

Modifying QGIS Project with C++

I have a QGIS project file, it has a point layer in GPKG format and online map layers. Coordinate System of online map layers is WGS 84 / Pseudo-Mercator. Point layer's default coordinate system is ...
4
votes
1answer
45 views

Manually setting spatial extent of custom map in QGIS 3.14

Due to customization wishes I created a map in Adobe Illustrator which means my .tiff file has no metadata like CRS, extent etc. when I export it. To manually set the spatial extent I would need an ...
3
votes
0answers
35 views

QGIS Convert Shapefile to MSSQL as geography type

I am using QGIS 3.16 and SQL Server 2019. I have a shapefile loaded into the project. I have been able to successfully convert the Shapefile to a spatial dataset in SQL Server. My method for doing ...
0
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0answers
20 views

Opening .gbdtable (.gbdtablx, .atx) files in QGIS

I was given is folder of .gbdtable files that I cannot seem to add to QGIS. Eventually I need these files in .asc or .bmp format, and am using QGIS to accomplish that. I've seen info on the web about ....
3
votes
2answers
188 views

Colouring points in the same colour as their nearest point/polygon from another layer in QGIS

I got two files, a multi-polygon file with polygons and points (File 1) and a file with points only (File 2). Our task is to fill the color of the points from File 2 with the respectively nearest ...
0
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0answers
19 views

GEE, How to Remove Vertex Pixels

I made a classification mask of the layer and get the following figure: I got several vertex pixels. A vertex pixel is a pixel that attaches to a bigger group by just one vertex (shown in red circles)...
2
votes
1answer
48 views

Using a comboBox to load a layer from PostGIS based on a field which is not the primary key

I am developing a small plugin in which I would like to create a dropdown menu that would enable the user to choose among a list of polygons (stored in a PostGIS database) according to their names. ...
3
votes
1answer
79 views

Working a PyQGIS Script in cmd, outside of the QGIS python console

I have a perfectly fine working script that runs within the QGIS Python Console and I would like to run the script outside of the software, preferably in cmd as a .bat, so then I can use task ...
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0answers
25 views

Projection problem for Chinese river file into WGS84 43N

I am using QGIS 3.10 and having issues with (re)projection of two shapefiles. For a map I am trying to make of a river network in Xinjiang China and South East Kazakhstan, I have found two shapefiles ...
1
vote
0answers
18 views

Loading legend items with hidden label by default in QGIS

Is there a way to set up the loading of the legend items in the layout manager with hidden labels by default? I can't seem to find the settings for that if there are any.
6
votes
4answers
258 views

Taking only the largest polygon from multi-polygon layer in QGIS

I have multi-polygon geometries in my file, and I want to take only the largest polygon within the multi-polygon geometry to further work with it. I tried using Geometry Tool Multipart to Single part, ...
5
votes
1answer
46 views

How variabilizing a part of the name of the data table used by QGIS ? I would like to use the same QGIS project for each year I'm studying

I created a map and a page layout for year 2018: It relies on data of the table temp_desendettement_communes_2018 (from a PostGIS database). I wish using the same QGIS project for other years, and ...
0
votes
0answers
57 views

Calculating the area of each county that has a specific land cover value (R or QGIS)

I need to calculate the area of each U.S. county that is covered by a specific type of land cover. I am using a county shapefile (polygons) and the land cover data is a raster that comes from the NLCD ...
2
votes
1answer
33 views

How can a spatial reference system be corrupt per OSR while valid per QGIS?

I have this coordinate reference system defenition: GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM[&...
1
vote
0answers
22 views

Connect to single table within a MSSQL database or terminate connection to database once layer added to QGIS project?

I'm connecting to MSSQL server '123' that contains 100s of databases and I am connecting to just database 'ABC'. 'ABC' contains roughly ~700 tables. Once I add the 'xyzTable' as a layer to my QGIS ...
9
votes
1answer
92 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 ...
1
vote
1answer
40 views

Showing only selected features of vector layer in PyQGIS [closed]

I am developing a Plugin in QGIS and I want to show only selected parts of a layer. How can I handle this with PyQGIS?
0
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0answers
38 views

Surface area of specific DEM region in QGIS [closed]

I am attempting to determine the 3 dimensional surface area of sea mounts and Island coasts between -1000m and 0m. I am using UTM in order to calculate area in km squared. I have created polygons from ...
2
votes
1answer
69 views

Calculating distances between buildings, plots and road network

I have three layers, see image below: A polygon layer containing building outlines (Purple) A polygon layer containing plot outlines (Yellow) A polyline layer showing the road network ( Red) What I ...
1
vote
0answers
26 views

WMS GetFeatureInfo not working

I created a WMS in a QGIS project and serve it with QGIS Server. When I click on a feature on the WMS map, no attribute information is displayed. I guess, the attributes are not exposed to the WMS but ...
2
votes
0answers
19 views

Group sublayers in WMS service to a single layer

I created a WMS service in QGIS that consists of several sub layers. It is a base map of cadastral data that is stored in different tables to get the final look. In the QGIS project for the WMS I ...
0
votes
0answers
52 views

Plotting time series in QGIS

I have a shapefile with points, like this: x, y, id, data -1.3345,-0.4760, 1, data.csv The data.csv contains: date, data 2020-01-01, 1 2020-01-02, 2 2020-01-03, 3 2020-01-04, 4 How can I plot the ...
2
votes
2answers
45 views

Adding Logo and Title to an HTML webmap created by Qgis2Web

I would like to add a company logo stored in my machine to a webmap created with qgis2web in QGIS. Also, it would be nice if I can add a title as well. Anyone could help me with that?
3
votes
0answers
18 views

How to prevent not visible objects (scale rules) from being identified?

In Symbology tab I am using rule-based symbols and I have defined visibility rules dependent on the minimum scale. Above some scale threshold some features are not visible as I expected. But when I am ...
0
votes
0answers
27 views

Converting Lat Lon in WGS84 format to UK NGR in QGIS [duplicate]

I have csv file that has WGS Lat/Lon, what I need to do is convert these to UK NGR i.e Easting/Northing. In QGIS there under Field Calculator I think there are some defined operator like $X and $Y ...
1
vote
0answers
23 views

Network Analysis Service Area Algorithm QGIS 3.16

I've been using ORS Tools to run my service area analysis for my research, because it was easier and quicker for me to get an isochrone, instead of the standard network analysis tools from QGIS, that ...

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