Questions tagged [qgis]

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

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22 views

Toggling multiple toolbars on/off in QGIS

In QGIS 3.12, from the View menu I go to Toolbars to toggle several of them on/off. However, when I toggle one (either way) I'm returned immediately to the previous screen. I've tried holding down ...
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0answers
17 views

Difference between datum transformations in QGIS 3.4 and ArcMap 10.7

Could someone briefly explain the difference between how datum transformations are handled by QGIS versus ArcMap? For example, I am under the impression that in QGIS you can simply select a ...
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16 views

Need to shade zip code polygons that overlap township polygons in QGIS 3.10

As the title says, I have shape files containing zip code tabulation areas and township names for the state of Massachusetts. In same cases, the zip code area is contained entirely within a single ...
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1answer
28 views

DEM interpolation, QGIS 3.10

A friend of mine gave me DEM resolutions of cells 5x5m, but there is something wrong with interpolation. When I try to make a cross-section of the terrain I get a pretty inaccurate cross-section, with ...
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1answer
18 views

SQL query builder in QGIS 3 doesn't display columns names

I'm creating sql queries using QGIS 3.8 DB Manager. The problem i'm facing is that when I write a query, I don't have any option to display the columns names : Is there any way to display the ...
2
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1answer
22 views

QGIS Field Calculator - How to get a value from another feature depending on the value of a field

I'm a total newbie at coding. I'm working with water catchments in QGIS. Runoff of some catchments feeds other catchments. I'm trying to get the cumulative run-off. so assuming each feature in the ...
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0answers
10 views

QGIS Ubuntu 3.4 SQL Query Composer in WFS Connection Dialog

The QGIS 3.4 documentation mentions the procedure of filtering the features of a WFS through the connection dialog box either by double-clicking on the layer of interest, or by clicking the "Build ...
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2answers
88 views

Is it possible to disable editing for certain layers in a QGIS project?

I want to disable editing some (but not all) layers in one QGIS project, while still having them editable in a different project. Is it possible to disable editing certain layers within a QGIS ...
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1answer
27 views

Shortest distance for multiple starting points

I am looking to calculate the shortest distance along a road network for multiple starting points. The reason I am not doing this manually is that I have more than 5000 starting points. Does anyone ...
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1answer
38 views

Possible to automatically export atlases from QGIS containing PostgreSQL views/tables?

I've managed to export several atlases automatically from QGIS with a Python and a .bat file, see Export several configured atlases with a Python script I'm using QGIS 3.10.2 on a Windows 10 PC and I'...
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1answer
34 views

Export several configured atlases with a Python script

I'm using @Alexandre Neto's Python code (from July 8 2019) to automatically export predefined atlas layouts, see https://gis.stackexchange.com/questions/272839/export-a-configured-atlas-with-a-python-...
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0answers
27 views

Difference tool QGIS shows too many Differences

After running QGIS Difference Tool, I get a lot of differences, but I don't know where they are coming from. The input files are almost similar... Input Image (overlay input almost the same, but from ...
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0answers
45 views

Creating one standardized color scheme across multiple maps

I am trying to map a grid-based polygon for a value named y. the goal is to compare the change in y by increasing other variable named x. y is continuous variable that when joined across all levels ...
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1answer
30 views

Buffering via PyQGIS 3. Got a 'NameError'. How do I define my iFace?

Code https://youtu.be/kvXbpN1fYmY I'm using \ because this is on Windows 10 so the slashes are not the problem layerName = 'Calapan_points' outFn = r'C:\Users\imper\Desktop\XYbuffer_tool\test.shp' ...
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0answers
39 views

How to reproject data from [-180 180] to [0 360]? [duplicate]

I have both a GeoJSON and shapefile of volcanoes along the Pacific Ring of Fire. The area I want to render in the map is right around the antimeridian, so Leaflet cuts it in half. I initially tried to ...
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0answers
23 views

QGIS attribute form table of contents highlighting is missing

When in form view in the attribute table, QGIS displays a "table of contents" beside the form, which usually highlights the feature being displayed in the form. Example: In two of my layers, somehow ...
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0answers
28 views

Export portion of .qgz to .dxf file [closed]

I am using QGIS. How do you export only a portion of the .qgz file database to a .dxf? The database is too large to bring all of it in, even with individual layers. Also, the CAD entities have a ...
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0answers
56 views

Many to many relationship in a QGIS Geopackage - fail

The current user manual has been unsuccessful in directing me to establish a many to many db relationship in a geopackage in QGIS (3.10.2 on Ubuntu w gdal 2x). After the airlines in the manual ...
2
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1answer
26 views

Combining overviews for a large multiband raster image?

I have several large rasters, complete with overviews. I have combined these as separate bands of a multiband virtual raster. However, QGIS performs very slow viewing this vrt. Is there a fast way to ...
3
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1answer
69 views

Transform Excel into vector in the Graphic Modeler

I have a graphic modeler with two inputs, a shapefile and an Excel file. I would like to make a join by attribute between the two. But I am confronted with a concern, the join can only do this between ...
0
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0answers
35 views

QGIS Distance Matrix tool

I want a distance matrix to calculate the mean distance between all points and all points with a common attribute (postcode district) in a single layer. Is there any way of doing this in QGIS? As an ...
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0answers
26 views

Rasterio: change singelband gray to singleband pseudo color for multiple colors

This is in reference to: Convert gray band from dataset to RGB with rasterio for population density however there is a difference. I have been playing around with QGIS which I had opened the ...
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1answer
48 views

Importing CSV as a point layer via the Python console. No point layer is loaded. How can I fix my code?

Code import os from qgis.core import ( QgsVectorLayer ) uri = r"file:\\\C:\Users\imper\Desktop\XYbuffer_tool\Calapan_XYpoints_comma?delimiter={}&crs=epsg:32651&xField={}&yField={}"....
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1answer
23 views

Spatial join - allocate values from joined polygon based on input polygon

I'm trying to determine population inside Special Flood Hazard Areas. To do this I'm doing a spatial join of census shapefiles with the FEMA National Flood Hazard Layer, using the Boolean field ...
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1answer
64 views

Transfer & maintain a relational database in QGIS - backend vs frontend [closed]

I'm going to set up a small db for my own use in QGIS. I can see only a few of the many tables will be spatial, but the ease of use and capacity of the widgets in QGIS are attractive. I won't writing (...
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0answers
19 views

Finding the distance of each “leg” in a path

I have a shapefile that contains ~550K polylines that each represents the Google Maps recommended path between bike share booths. I laid the shapefile on top of the shapefile for census tracts in New ...
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0answers
33 views

Slope and hillshade layer not continuous in QGIS

I have been trying to create slope and Hillshade rasters from a DEM raster, which is in UTM11N. I tried different ratios (vertical to horizontal) but everything is in meters so it should work fine. I ...
1
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1answer
23 views

Expand QListWidget in QDockWidget in a QGIS plugin

I am working on a QGIS plugin. The plugin has a panel with two QListWidget and buttons, labels, etc. I would like to expand horizontally and vertically the lists if panel resized. I set the hsizetype ...
0
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0answers
47 views

Movement in shortest path

I am new using QGIS. In my project I need to find the shortest path between different layer points. I did this using the network analysis shortest path tool for single points and OD-matrix tool with ...
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0answers
21 views

QGIS 3.10 atlas / composer, avoid missing text edge of map?

How to avoid missing texts near edge between map images? I have vector topographic map which need to cut through map names. When I create atlas project using Composer, those cutting text are missing ...
2
votes
1answer
59 views

Loading GeoTiff to QGIS - nothing displays

I have generated a GeoTIFF with CRS set to WGS 84: geotransform=(xmin, xres, 0,ymax ,0, -yres) output_raster = gdal.GetDriverByName('GTiff').Create(filename + ".tiff",ncols, nrows, 1 , ...
0
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1answer
43 views

PostgreSQL connection doesn't show up in Data Source Manager

I have data for a PostgreSQL connection. After writing the data in QgsSettings. The connection works but in the Data Source Manager under PostgreSQL connections is nothing documented. After I restart ...
2
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0answers
26 views

Differences in counted population between raster and polygonized values - QGIS

I'm slightly puzzled with the "polygonize" tool in QGIS. I'm working on population data, and therefore have clipped the NASA SEDAC Population count raster to my country of interest (Mozambique). ...
0
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0answers
22 views

Context menu on the mapcanvas [closed]

Is there any way to add context menu on the mapcanvas? (on mouse right click) I know how to add context menu for the treelayer view. Can somebody please help me with this.
2
votes
1answer
42 views

1-n relationship by location in QGIS

I have a polygon layer and a point layer. According to the QGIS documentation, the childlayer has to have a foreign key. Unfortunately, my child layer has none. Is there a way to form the relation by ...
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0answers
28 views

Creating a points layer from a CSV file with distances along a line, based upon a known vector in QGIS?

I have transect data with know start and end lat/long and length for each transect, which I have made into a vector shapefile in QGIS. I want to add points for each sighting along the transects, which ...
0
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0answers
21 views

Restricting the turn angles in least cost path in QGIS

I have calculated the optimum path between two points based on a DEM file; My raster cost is based on elevation and the least elevation is regarded as optimum. The output has some zigzag pattern which ...
1
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0answers
37 views

Displaying only the negative or positive contours?(not labels)

I have a coastal environment and I would like to hide land contours and keep isobaths only(and vice versa probably). One solution would be to superimpose the land polygon, but I do not want to do that....
1
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1answer
21 views

postProcessAlgorithm in processing algorithm for QGIS 3.10

I've created a processing script in QGIS 3.10, but can't seem to achieve the last step of styling the processed layer. My script follows the new easy processing script format that have come back since ...
2
votes
0answers
27 views

Saving Processing algorithm output to string instead of file.geojson [duplicate]

Is there any way to save processing.run("native:algorithm") output directly to string instead of file or temporary layer? I'm aware of saving output to layer and exporting features using ...
0
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2answers
40 views

Imported DMS points from CSV to a point layer. Do I need to convert DMS points to Decimal Degrees to use metric distance units for Buffer?

DMS - Degrees Minutes Seconds Buffer tool only shows degrees as the distance unit (not meter or kilometer) Do I need to convert DMS points to Decimal Degrees to use metric distance units for Buffer? ...
1
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1answer
63 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....
2
votes
1answer
31 views

How do you merge multiple polyline features into one contiguous feature in QGIS?

I created a shapefile from public GIS data, that I wanted to display in Google Maps for presentation purposes. The original .shp used small line segments for roads. Maybe a picture will make sense: ...
1
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0answers
19 views

DEM elevations not appearing when rendered to single band pseudocolor

When rendering DEM file to single-band pseudocolor, the elevation values are not appearing. Attached are images of the proper template and my layer properties. Please let me know what other data would ...
0
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0answers
32 views

QGIS parallel processes

I am processing a bunch of GPS data using a Qgis python script. The processing takes a LONG time to execute and when it is executing I notice that only a single CPU is pinned at 100%, the remaining ...
6
votes
1answer
129 views

Why QGIS 2 and QGIS 3 return different value for $area function?

I measure the area of a polygon with the QGIS Calculator: The cartesian area($ geometry) calculation function gives the same result for QGIS versions 2.16 and 3.4.5, but it is different with the $area ...
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0answers
23 views

Watershed Delineation for Specified Streams

I have a set of streams (currently a shapefile (line)) which I need to delineate the watersheds for. I have attempted to use various QGIS tools, however, each tool I have tried is for delineation of ...
0
votes
1answer
31 views

How to prevent plugins from loading at start? [duplicate]

I'm trying to set plugins to unchecked at start in QGIS-3.10, I thought it could be possible at the "Manage and install plugins" menu; if I uncheck the plugins they disappear from the menu, but ...
-1
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1answer
30 views

Creating a greyscale bathymetry map of the world in QGIS

I am looking to create a greyscale bathymetry map of the world in QGIS which I can then output as SVG contour lines. Maybe there is somewhere where I can find and download greyscale vector tiles of ...
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0answers
48 views

UK BASED SMALL TELCOM COMPANY SPECIALISING IN BLOWN FIBRE [closed]

WE ARE A UK BASED SMALL TELCOM COMPANY SPECIALISING IN BLOWN FIBRE. We are after a reliable and straight forward software to help our surveyors map the routes on google earth, attach nodes to ...

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