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Questions tagged [qgis]

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

-1
votes
0answers
14 views

Installing GRASS addons in QGIS 3- r.local.relief [on hold]

I have been searching for possible ways to install an GRASS addon to QGIS. This issue was mentioned in some earlier posts, for instance: How can I add r.local.relief to the QGIS Processing Toolbox? ...
6
votes
0answers
55 views

QGIS: beautiful HTML/Javascript terrain profiles won't show in Atlas print

I managed to automate the creation of terrain profiles, using the beautiful "Highcharts" Javascript framework. The data source of the profiles is stored in an attribute called "elev_data" of my ...
0
votes
1answer
36 views

QGIS : Relocate a layer's source file [on hold]

Is it possible to change the directory of a layer's source file without deleting and re-importing the layer?
-1
votes
1answer
34 views

Any algorithm to draw lines inside a shape? [on hold]

Let's say you have a circle and have all the coordinates (x,y) that make up the circle.... How would you create lines (vertical and horizontal inside it? What about a rectangle? What if you have the ...
-2
votes
0answers
27 views

Processing Toolbox has gone missing from QGIS 3.4 Win OS. Any alternate method to activate Processing Toolbox other than through the Plugins Manager? [on hold]

QGIS Crashes when I try to activate the "Processing" by clicking the Check Box in the Plugins Manager as advised in earlier answers.
1
vote
0answers
21 views

QGIS i.topo.corr not outputting file

I am very new to working with QGIS, but am familiar with ArcMap. I am performing i.topo.corr with the GRASS extension using Landsat 8 bands 2-7. For my parameters: Band 2 SRTM Raster elevation model ...
0
votes
0answers
17 views

QgsMeshLayer in memory

I am trying to create a Meshlayer in memory and tried this simple test in QGIS 3.6: from qgis.core import QgsProject,QgsMeshLayer proj = QgsProject.instance() uri="1.0, 2.0 \n2.0, 2.0 \n3.0, 2.0 \n2....
1
vote
0answers
29 views

Deleting text from Map Items in QGIS print composer?

I have been using QGIS for some time, and what I am experiencing is not something that I have had issues with before. It appears to be a gitch. I created a map in QGIS 3.6.2. Then, I exported it as ...
1
vote
1answer
34 views

Accumulate selections by expression using a for loop (Pyqgis)

I need to run a for loop to select features by their attributes, because the values are within lists (strkey and strvalue). I'm using the following script: k=0 v=0 layer = iface.activeLayer() for ...
1
vote
1answer
53 views

QGIS. Polygon doesn't repeat itself

In QGIS, I represent a polygon of the El Niño regions on the Pacific Ocean, as seen below: Now, what I need is that the regions of Oceania and East Asia are shown on the left side of the map, similar ...
1
vote
1answer
26 views

QGIS: Smoothing two polygon sets where polygons are nearly adjacent

I have two polygon sets, one representing cities, the other representing school districts. I am trying to create a relationship between cities and districts, but I have a problem where the cities and ...
-2
votes
0answers
29 views

Scaling heatmap in QGIS? [on hold]

I am producing a heatmap of England cities regarding number of vehicles, i want to show cities with high and low number of vehicles using heatmap, over 5 years. How do I do that using heatmaps in ...
0
votes
3answers
91 views

Export longitude and latitude

I need the exact values of longitude and latitude to do further calculations with those. Best case would be to have a list with all those dates and do the calculation with this. I exported from ...
1
vote
3answers
68 views

QGIS: keep the outline of a building

Is there a way to keep the outline of a building? I am using a shp with lines showing the walls of a building (originally CAD file). I would like to keep only the outline of the building either as a ...
0
votes
0answers
26 views

Export OGR feature style data from QGIS for use in GeoPDF

I have a fully formated map in QGIS from which I wish to make a GeoPDF. I followed this and this tutorial and generated a simple version of my map without much problems. I am however looking for an ...
2
votes
1answer
50 views

Add pixels to a raster image

I have a georeferenced raster with water depth values and I would like to add more pixels in order to extend my raster as far as the coastline (like in the picture, dark blue has no values). How can I ...
0
votes
0answers
24 views

Creating drive time buffers in QGIS [duplicate]

I have a set of points in QGIS and I am trying to create drive time buffers around them, how do you do that? I am using QGIS 3.6.3.
0
votes
0answers
14 views

Processing commands not producing shapefiles in Python 3.7

I am using a standalone python 3.7. QGIS script to reproduce a commands that work when using the QGIS interface. The code works in the standalone script (i.e. produces no errors or warnings), however ...
0
votes
0answers
23 views

Python error on QGIS

We are doing the slope analysis for one of our clients and can find the following error every time we do the analysis. We have not faced this situation in the past. The QGIS version which are using is ...
0
votes
0answers
21 views

Saving changed positions in SQL Server table X, Y columns

I have a SQL Server table with X,Y columns linked to QGIS 3.6, and I made a virtual layer of it using "MakePoint(X,Y,CRS_id) as geometry". Now I want to shift a point in the map and have the change ...
-3
votes
0answers
55 views

GIS, drone image processing [on hold]

I wish to extract features (vegetation, roads, buildings, etc.) from a TIFF image generated using Pix4d. Can this be done in QGIS?
1
vote
0answers
34 views

Load a shapefile using PyQGIS (QGIS 3.4) on ubuntu?

I want to create a standalone application based on QGIS API. Here is my source code to load a shapefile: import sys from qgis.gui import * from qgis.core import * from qgis.core import QgsProject ...
1
vote
0answers
29 views

How to get back the Processing Toolbox? Re-installation also doesn't work! QGIS crashes when I try to activate it using Plugins Manager

Processing Toolbox missing after I copied a python script from the Scripts folder to my local folder, and QGIS crashes when I try to active the "Processing" under the Plugin Manager
2
votes
0answers
24 views

.ecw file not imported in its projection in QGIS

I have a .ecw aerial image and one of the associated files is .prj, which i assume defines the Coordinate Reference System of the image. The .prj is as follows: PROJCS["PNG94_PNGMG94_zone_55",GEOGCS["...
1
vote
0answers
26 views

QGIS Vector Tiles Reader does not apply style

I have downloaded Vector Map Tiles from Open Map Tiles and have these tiles as local .mbtiles file. In QGIS there is the plugin called Vector Tiles Reader and I have the following problems: I ...
1
vote
0answers
28 views

QGIS: habitat suitability/combining raster layers

I have created a number of raster layers for different environmental factors (slope, roads, rivers, forest cover) and want to combine them to find areas where the 'ideal' aspects all overlap. For ...
1
vote
0answers
31 views
+100

QGIS+PostGIS set atlas extents to include atlas feature and point

I have a QGIS print layout with an atlas layer for which I would like the map extents to show the current atlas feature and a nearby point. The layer provider is postgis. It seems the only way to do ...
1
vote
2answers
36 views

Cannot read pixel value from DTM raster with QGIS

I am using this DTM: http://ags.cuzk.cz/arcgis2/services/dmr4g/ImageServer/WMSServer?request=GetCapabilities&service=WMS At ArcGIS I am able to ready pixel value of the raster but at QGIS it ...
1
vote
2answers
31 views

Substracting raster values from 2 rasters with different cell sizes

I am working with two raster files. The first is a DEM and the second an elevation-correction file. Both files display the same geographic region. My problem is that the cell sizes of both files aren'...
0
votes
1answer
31 views

How do you find which points connect to other points

I have points that I have created from vector lines. To be more specific these points are end and start points of vector lines. But what I want to do now is identify which points connect to each other ...
1
vote
1answer
26 views

Grid lines and text together with Atlas. Problems with some scales for each map

I'm having trouble using the "Grids" option in the QGIS 6.3 composer layout. If I define the Interval units in Centimeters the coordinates on the map (text) are NOT referenced to the coordinate ...
2
votes
1answer
31 views

Adding page number in QGIS Report?

Adding page numbers in QGIS Layouts can be done with the [% @layout_page %] expression. In Reports, however, the [% @layout_page %] expression always remains "1" How do we insert the page number in a ...
0
votes
0answers
13 views

QGIS 3 (Mac) crashes when opening .bag bathymetry files [on hold]

Just upgraded to MacOS Mojave, Python 3.6 and QGIS 3.4.8, hoping to be able to open a .bag bathymetry file. Every time I try, QGIS instantly crashes. I uninstalled QGIS and tried 3.6.3, no change. I'm ...
1
vote
1answer
29 views

Reports with page footers …?

I don't really get the behaviour of QGIS new reports (3.X) ... I inserted an attribute table in a report. this table is spanning over several pages. I would like to create a page footer with the page ...
3
votes
0answers
58 views

Saved QGIS Project is empty!

I worked a complete night in a project involving a research of my group. When I tried to open it today, it's blank, there are no layers at all. As you can see in this link the thumbnail in the home ...
7
votes
2answers
102 views

Positioning multiple attributes separately in a label

I'm using QGIS I've got a basemap with the Texas landgrid for all of the counties in the Permian Basin. There are various attributes associated with the sections in the grid, but I only need 2 to ...
2
votes
0answers
33 views

Slow loading of QGIS project?

I have a number of standard projects set up for QGIS users. Some of them take more than 5 minutes to load. Things recently got much worse suddenly - and I want to track down why. Are there any ...
0
votes
0answers
34 views

Digitizing contour lines from a picture in QGIS

I have a map with isobaths (water depth), like in this picture, and I would like to digitize them. Is there any tool or procedure in QGIS that can recognize the lines in the picture and create a ...
0
votes
0answers
17 views

The picture is getting cut when I put my ASC file of altitude variable

I am trying to project my ASC file of altitude variable on QGIS. But its picture is getting cut and a visual cuts and bruises are seen in the picture. Can you please tell me why is it happening?
0
votes
1answer
46 views

Using QGIS to Make Poster Maps? [closed]

I am very new to GIS and am trying to use QGIS 2.8 to make a very large display map of Southern Ontario, roughly 4 feet by 8 feet. I would like to use aerial imagery, and am thinking of using the Bing ...
1
vote
1answer
45 views

Non-spatial SQL Server table with X,Y fields directly in QGIS?

In QGIS 3.6 I linked a SQL Server table with a field 'X' and a field 'Y', together representing positions in a known co-ordinate system. How can I show these positions directly in QGIS, without ...
0
votes
2answers
43 views

Transforming time series gridded meteorological data from .csv file to multiple .shp files (one per date) with pyQGIS

I downloaded gridded meteorological data as .csv file from the JRC CGMS database for a territory of interest. The file has data for predefined point locations over the territory in a regular-spacing ...
0
votes
1answer
19 views

QGIS 3 - Polygon symbology RGB based on different columns

I want to symbolize several values from one layer using R, G, and B values. So, column 1 would be the blue aspect, from 0-255 based on min and max values, column 2 would be green, and column 3 would ...
1
vote
1answer
35 views

Geometry generator in print composer

I am trying to create folding marks in the QGIS-print composer. Basically they are just markers along a line - with the twist, that the spacing is not even. I want to avoid having to create several ...
1
vote
1answer
37 views

QGIS 3 Show Red Vertex Crosses in Edit Mode

I don't know if this is a change in QGIS 3 or if I managed to turn it off somewhere, but in previous versions of QGIS when a layer was in edit mode there were red crosses on all the vertices. I ...
1
vote
1answer
25 views

Expression by Virtual Layer

On Qgis 3.6.3 I'm trying to create a virtual layer obtained by merging 12 shp (with the columns named and ordered in the same way) with the expression select * from _January, _February, _March, ...
1
vote
0answers
20 views

Saving raster layer to disk using Python: TIFF raster layer loses data type when saved with QgsRasterFileWriter

I'm trying to save a TIFF image stored as a raster layer. The image is fetched from a server so that its source (the url passed when creating the layer) is a HTTP url: the image should be saved to ...
2
votes
0answers
26 views

QGIS - How to render QgsMapCanvas on QApplication's main window

I am working with C++, QT 5.11.3, Visual Studio 2015 and QGIS 3.7 I'm trying to develop QT c++ application that uses the qgis api. I want to display simple raster and vector map in my qt application. ...
2
votes
0answers
18 views

Adding shape of defined dimensions in metres on an WGS84 ellipsoid using PyQGIS in QGIS 3.4

How can I place the shape of defined dimensions (in metres, 5000m X 2000m) measured around the WGS84 ellipsoid at a location on the ellipsoid (51 degrees N 2 degrees W)? Joseph provided a very ...
0
votes
0answers
23 views

Simple “Clip” geopackage with all attributes using R/ArcGIS/QGIS [closed]

I have recently discovered geopackages and SQLite. I have a geopackage containing a shape (main.stand) and multiple tables (main.assortment, main.treestand,...) of individual forest stands. Some of ...