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Questions tagged [qgis]

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

5,586 questions with no upvoted or accepted answers
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437 views

Is there a tool that shows dimensions during editing?

Is there a plugin or tool providing following functionality: I select 2 points (or vertices) - it shows the length between this points When i edit the point (or move vertex) the length automatically ...
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254 views

How to calculate radius of curves in a polyline with QGIS?

I have a polyline made of curves and I would like to know if there is a way in QGIS to calculate the radius of the curves?
5
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882 views

Print Composer Template produces empty map?

I have a print composer template which I'm trying to populate with different subset queries from a CSV-derived vector layer using the Python API. However, all the output PDFs contain everything except ...
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1k views

QGIS cannot open output layers

I have problem with QGIS 2.0.1. Everytime I run tool from SAGA or GRASS, I get exactly the same error, for example: Oooops! The following output layers could not be open Channel Network: /tmp/...
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419 views

Can extracting raster values work in polygons' CRS without raster resampling?

I am trying to extract raster values using polygon layer with different CRS. Raster is in WGS84 (EPSG:4326) and the polygons in UTM (EPSG:23031). 1. If I want to work in the projection of the ...
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660 views

How to debug Quantum GIS PlugIn Visual Studio DLL?

I have developed a Quantum GIS plugin layer using Microsoft Visual studio and placed it in my plugins folder of my customized QGIS application. I now intend to debug the DLL using Microsoft Studio. ...
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2answers
2k views

Publishing QGIS project on GeoServer?

Is there a way to prepare a project on QGIS with many layers and to publish it under WMS service on GeoServer?
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0answers
36 views

Setting default raster statistics extent in QGIS?

I recently found the setting in QGIS to rescale raster symbology using the current extent, which is really handy (Layer styling > Min/Max Value Settings). My question is - can the default extent be ...
4
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0answers
38 views

Displaying images as part of multiattribute labels using QGIS

I would like to display images referenced in an attribute column as part of a multiattribute label, so that I can eventually print them with the map. I do not want to display geotagged images, since ...
4
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0answers
24 views

Difference between merge and create virtual raster

I have the DEM of a defined region that has been split into sub-DEM with a resolution of 1 km x 1 km. When I merge the sub-DEM to create a single DEM (Raster -> Miscellaneous -> Merge), the overall ...
4
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1answer
111 views

MODIS Fire Product tile conversion to GeoTIFF problem

I downloaded a tile (selected tile in the picture) from https://ladsweb.modaps.eosdis.nasa.gov/search/order/3/MOD14--6/2019-08-09/DB/Tile:H25V6 I used gdalinfo on the file. It's output is Driver: ...
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0answers
44 views

QGIS export to PDF - rasterize only basemap layers but keep others as vectors

I am building my own map in QGIS 3.4 in which I created a basemap from ESRI satellite imagery and a ESRI hillshade overlay. On top I have several custom vector layers (country borders, city names etc.)...
4
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2answers
82 views

Calculate the travel time from locations to the closest N points

I want to calculate the travel time (based on walking time) from locations to the closest N points of another dataset. Then I want to create a hull around those N closest points per location Is this ...
4
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0answers
34 views

QGIS shared project (monitor changes)

I have a software-development background with a powerful use of svn and git. I work now for a public authority with two offices far from one another. Two other colleagues and I are sharing several ...
4
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0answers
69 views

Rotating image by specific angle in QGIS plugin

I am using the Freehand Raster Georeferencing code in a widget to help size and locate site plans on aerial GE backdrops. I need to find a way for a user to input a specific angle of rotation and the ...
4
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1answer
61 views

Adding up several rasters to show the change

I want to add several images such that their change is shown in different colors. Such as the following in which I simply added two images in their grayscale. But I would like to have a colored ...
4
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0answers
82 views

Finding easiest path to walk on topographic map?

I want to make the shortest path between two points, but the thing is that there's a hill in the middle. I used Naismith's rule to calculate how the slope interfers in the walking time and I did the ...
4
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0answers
208 views

How to divide polygon into smaller 'equal area' polygons in QGIS 3.6?

There is a plugin in QGIS 2.18 called Polygon Divider which Divides polygon into smaller 'equal area' polygons of a specified size but in QGIS 3+ version there is no Polygon Divider plugin to install. ...
4
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0answers
56 views

Snap LineStrings considering direction in QGIS 3

I have 2 projected shape files: Roads (red) and public transit routes (blue): I want to snap the PT routes to the roads, but because of inaccurate marks sometimes the routes are snapped to the wrong ...
4
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0answers
293 views

How to use ATOM FEED Data in QGIS 3.6.1?

I would like to know how I can work with ATOM FEED Data in QGIS. In ealier QGIS versions this worked with the Plugin "INSPIRE ATOM Client", but this Plugin doesn't work in the current version. An ...
4
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0answers
94 views

Creating a segment for fixing water pipes and finding disconnected areas

I'm wondering if there is a tool for this problem. I'm using QGIS 2.14.2. Basically I want to select a pipe and find closest valves there is and to turn them off. After that I need to find all pipes ...
4
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0answers
524 views

Running OTB Random Forest Classification

I am having trouble processing a satellite image using the RF (Random Forest) classification, that is a machine learning algorithm in the Orfeo Toolbox of QGis 2.18.1. When I run the Tool, the ...
4
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0answers
114 views

Change from LineString to MultiLineString when saving layer edits in QGIS

In QGIS, when a user creates a new single part line in an open editing session for a “Multi-Line” SpatiaLite dataset, the QGIS data type is initially a “LineString”. But, when the user commits the ...
4
votes
1answer
504 views

Enabling QGIS Official Plugin Repository in the 3.4.1 Version?

I am using QGIS version 3.4.1. Recently, I cannot install new plugins. I have looked in the plugin setting. It seems that the link is blocked. The address is "https://plugins.qgis.org/plugins/plugins....
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0answers
445 views

QGIS 3.4.1 Extensions Repository not available

In my QGIS 3.4.1 installation (Windows 10) the extensions repository says "unavailable", like in this older post: Why I can't install plugins?. I already added the repository with "HTTP" instead of "...
4
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1answer
161 views

Accessing PostGIS data in QGIS?

I've created a two new PostgreSQL users; one that is supposed to have read-only privileges and another one that should have most privileges (admin-user). When I connect/log in to the new users in QGIS ...
4
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0answers
230 views

Question marks (“?”) in QGIS layer panel when using svg markers defined with “Data defined override”

When using svg marker symbols and set the path to svg file via Data defined override the svgs display well in the map canvas, but not in the layers panel (applies for QGIS 2.x and 3.x). svg marker ...
4
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1answer
108 views

Selecting or highlighting upstream elements

I would like to use the information from the Swedish SMHI related with their hydrological model elements (catchment areas) that have a Containment hierarchy structure, each element has the information ...
4
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0answers
253 views

How to use a WCS layer in QGIS for processing?

I have a GeoServer serving raster dem data out via WCS and can add the layer easily to QGIS (3.2) but when I try to use it as the input for an operation (e.g. HillShade) I get an error. Processing ...
4
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0answers
142 views

Offline editing solution for small GIS project with multiple editors?

I have a specific use-case that I cannot seem to find any solutions for online, so any and all advice would be most welcome. Some basic details: I am part of a small academic organization (a research ...
4
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0answers
96 views

Equal length dashed lines while using 'segments_to_lines' in QGIS

I want to create tapered lines with a dashed line stroke (to style intermittent streams). I followed this tutorial to create the taperered lines, basically using Geometry generator with the expression ...
4
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0answers
163 views

Local grids with rotated north in QGIS

Like many people in geology and archaeology I need to work with local grids that have eastings and northings from a specific reference point, and typically have a difference alignment/direction of ...
4
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0answers
103 views

Single Sided Buffer Error QGIS

I have delineated a shoreline and created an offset "buffer" of 75' and 250'. When projected onto the screen it appears as though a computation error has occurred and the buffers extend onto the left ...
4
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0answers
107 views

Adjusting georeferencing of GeoTIFF?

I have three thermal IR images of a boat acquired by a drone as it flew overhead. The images were taken at one second intervals, are GeoTIFF files and overlap one another. I don't know exactly how the ...
4
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0answers
249 views

Investigating PostGIS table not showing in QGIS

I created a table in Postgres: create table eric_zs as select z.id, z.name, st_multi(st_union(a.geom)) as geom, count(*) from geo_as a inner join geo_zs z on a."ZS_id" = z.id group by z.id, z....
4
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0answers
138 views

Is there a specific tool to globally manage visibility/theme in QGIS?

In short : I'm looking for a Visibility Manager (QGIS 2.18) ou Theme Manager (3.0). I couldn't find it in the QGIS plugin list or in different methods on gis.stack. Maybe I missed it and maybe it ...
4
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0answers
265 views

When does a QGIS .qix spatial index of a shapefile need to be re-created?

I understand the basics of spatial indexes but would like to understand when exactly a spatial index would need to be re-created or updated? The reason I ask is because when a folder was moved to a ...
4
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0answers
112 views

Speed execution of PyQGIS algorithms

I don't understand why if I do "manually" some algorithms I get results much faster than when I insert the same in a pyqgis code (with the same input). This happens, for example, with the extract ...
4
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0answers
80 views

Set background or text color depending on expression in an attribute table in QGIS composer

I am using QGIS 3.0.2. I am working on a print composer including an attribute table. I would like to set different colors to each rows, depending on an expression, refering to an attribute. I didn't ...
4
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0answers
85 views

Different fonts in QGIS2threejs

I'm working with QGIS2threejs for quite a while and it is a great tool! Changing font for the 3D presentation is easy, just change it in the css file. But here is my question: Is it possible to change ...
4
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2answers
313 views

Density map of pedestrian paths and footways in QGIS

I need to identify public places within pedestrian areas in London, so I need to calculate the density of both pedestrian links and footways. I have classified my data according to the categorization ...
4
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0answers
79 views

Halftone effect gridded points inside polygon

I am trying to create smooth looking polygons by gridded points in QGIS (2.18.16), with a fading effect towards the boundary of the polygons (halftone effect). By using the 'fillGrid' function from ...
4
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1answer
158 views

Use DEM elevation attributes in vector polygon?

I am modeling glacier retreat scatching polygons on DEM surface trying to come out with 3D scatch. Is it possible to adjust "height" of polygon to follow elevation of DEM surface (eg. glacier height ...
4
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0answers
211 views

QQIS Automatically Converts UTC Date-Time to Local?

I imported a WFS layer from a geoserver into QGIS and also into a web service that is based on Cesium. The geoserver fetches the data from Elastic search and serves it out as WFS. The date-time ...
4
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0answers
72 views

Creating Raster that sums up input polygons using QGIS?

I am using QGIS and I have a shapefile with buildings. From these buildings, I have built Buffer with variegating radius. The Buffer also have data about the demand for Parking spots for each building....
4
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0answers
239 views

Installing third party python library in QGIS 2.18.x Windows

We are running into a strange behaviour while trying to use pyoidc with QGIS 2.18.x windows standalone version. Due to pip/pipy no longer working with QGIS 2.18 (see this post), we installed the ...
4
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0answers
209 views

Connectors do not appear automatically in easy custom labelling

I'm using the easy custom labelling plugin in QGIS 3. When I move a label away from its associated polygon a connector does not automatically appear as in QGIS 2.18. How do I get connectors to appear ...
4
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0answers
77 views

Bookmarking the rotation, scale, and extent in QGIS

I have one map that I want to bookmark at multiple rotations/orientations. However, when I use the bookmark tool to capture the view, I am only able to capture the scale and extent of each view, and ...
4
votes
1answer
152 views

Sharing properties for SQL server table in QGIS?

I have a project where most of the layers come from a SQL server. Most of the layers contain pointers to, and/or drop down list for, attributes so that there is consistency in data entry. This project ...
4
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0answers
93 views

Speed up identify in QGIS

I have just transferred my Postgis database onto an RDS server, and there is a bit of a performance hit when using the Identify tool in QGIS (3) compared to localhost. I presume this is mostly network ...