Questions tagged [qgis]

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

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Installing and Starting QGIS server on Windows 7

I have downloaded and installed QGIS server as per the instructions on the web page https://docs.qgis.org/3.4/en/docs/user_manual/working_with_ogc/server/getting_started.html#installation-on-windows, ...
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32 views

Merging attributes together [closed]

Can you help me with many attributes (points) in attribute table? I have many (5636) attributes in one layer (vectro layer) with different number and I need merging only for 3-5 attributes. The ...
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1answer
78 views

Joining fields with long field attribute names

I am working with the "Joins" option in QGIS 3.10, which joins the fields from two attribute tables based on a common shared attribute column. However, this does not work for attribute values with a ...
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1answer
105 views

Widget html QGIS

I am creating a mask in QGIS through the html widgwet , which, based on the value of an expression, creates or not circles. I created my css structure but I cannot integrate the question (the ...
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1answer
37 views

Layer is being add to 2 groups instead of 1

I'm trying to create 3 group layers, depending on parameters of two lists, but reg_imobiliarios layer is added to auxiliar and referencia groups. In short, all the layers are in the correct group, ...
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30 views

How to iterate over features until condition (remove all values larger than 3 times RMSE) is met in QGIS

I have a vector dataset containing GPS locations of different vehicles and a (polygon) road network dataset in QGIS. To be able to say something about the quality of the GPS-measurements, I would like ...
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25 views

How to Composite Monthly Nightlight Data in QGIS? [closed]

I am trying to composite the Monthly Nightlight (VIIRS.M_VCMCFG) product extracted from NOAA’s NCEI website. What is the procedure to create a yearly nighttime data in QGIS?
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1answer
54 views

What are the benefits of using a SQL connection over .CSV? [closed]

I am currently storing 6mln addresses and their coordinates in a .csv file. The bulk of my work involves loading these 6mln addresses into QGIS and then investigating sub selections (usually 100k-ish)....
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19 views

Converting the x and y co-orinates in a shapefile from feet to meters. NAD_1983_StatePlane_California_VI_FIPS_0406_Feet

I have shapefile which has the current co-ordinate system as: "NAD_1983_StatePlane_California_VI_FIPS_0406_Feet." Projected Coordinate System: NAD_1983_StatePlane_California_VI_FIPS_0406_Feet ...
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19 views

How to add additional GRASS modules to QGIS 3.2?

I like to use the v.kriging tool from GRASS (https://grass.osgeo.org/grass7/manuals/addons/v.kriging.html) in QGIS 3.2 but its not in the processing toolbox. Is this possible to import this tool and ...
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1answer
41 views

Reading Elevation Data from a DSM file using Python

I am new to GIS processing and I have a DSM file with a .tif extension. I would like to read the elevation data from this file using python or QGIS. I can view this file on the delair web ...
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1answer
350 views

How do coordinate reference systems and projections relate to each other?

I would like to resolve some general confusion of mine concerning the terms (and concepts) of "coordinate reference system" and "projection". The way I initially understood these terms is that a CRS ...
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1answer
35 views

Show all contour line labels in Layout in QGIS

I created a map with labeled contour lines. When I am now adding the map to the layout view not all labels appear (e.g. 2000, 2500 and 3500 meters has a label, but not 3000) [. In the original map ...
3
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1answer
55 views

Changing elevation values of DEM

I am no expert in QGIS and I've already spend quite some time to find an answer to this, but I could not. Could anyone tell me how to change the elevation value of DEM? The one I have has been ...
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1answer
39 views

Calculating list of existing polygons with distances from newly created QGIS/PostGIS

I have two polygon tables (SRID=4326) in postgres: t_areas and t_sites. Once I insert through QGIS 3,8 a new area in t_areas I'd like PostGIS (by a trigger) to list all sites within a certain km range ...
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1answer
41 views

Display SVG icons in polygon layer using PyQGIS3

I have this code to set SVG icons only for selected features. It works, but only with point geometry, while I have a layer with polygon geometry. How can I modify this code to works also with polygon ...
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1answer
63 views

Placing points along line in QGIS

I am fairly new to GIS. I have a line of a survey track that is approx. 380km long. I can correctly measure this using $length, and with the measure tool. I am using a custom transverse mercator ...
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15 views

Exporting imagery data from Geocortex Viewer and then import it into QGIS?

I have access to a Geocortex Viewer (for HTML5 2.11.0, apparently) with some imagery that I want to combine with several other layers I have in QGIS. I want to get the imagery out of Geocortex Viewer ...
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35 views

Image loads uncentered and at a wrong scale [closed]

I am new to QGIS. My project CRS is EPSG:4326 and I have five rasters in this CRS. The problem comes when adding a raster file from MODIS. I am downloading the world GEOTIFF image from : https://...
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1answer
27 views

How to merge selected features with different attributes in QGIS?

I want to merge several features with attribute values that fall within a certain range. I use Select by Expression to select the relevant features, but when I click merge selected features, QGIS ...
3
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1answer
41 views

Random points within a grid cell on a line

I'm trying to create random points on a line within a grid cell. I have a river layer within a state boundary. I have placed a grid over the state boundary. I would like to assign 5 random points ...
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1answer
32 views

Use Python to change a print composer layout item's extent in QGIS 3

I have a QGIS project and in that project there is a print composer layout titled mainmap. This print composer layout has my desired layout items like a title, scalebar, and legend. mainmap also has ...
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1answer
49 views

QGIS SAGA “Kriging” tools doesn't work

I try out different methods of point interpolation for a digital terrain model. For this purpose I tried to run the "ordinary kriging tool" from the SAGA Tools with QGIS 2.18 and QGIS 3.2. When I run ...
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1answer
41 views

enabling scrolling hstore key/value field

The key/value widget applied on a Postgres hstore field conveniently shows, for a record, a sub-table containing the various keys and values. If there isn't enough space in the form, this sub-table is ...
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19 views

QGIS Widget on Qt Designer Mac

I would like to use a QGIS custom widget in a UI window on Qt Designer for Mac. I only have the Qt widgets and cannot find a way to see the QGIS widgets. I have Mac OS Mojave 10.14.6, Qt Creator 4....
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31 views

Reording fields in Identify Results panel

What can be done to modify the fields order in the Identify Result panel, idealy without re-creating a new layer? Modifying the table field order or the UI field order, as described in this answer, ...
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1answer
40 views

Join attributes by location fails to join to selected features

There's an issue when I perform the "join attributes by location" tool. I have a simple polygon layer representing urban areas. I also have a point layer with human population estimates. My aim is to ...
10
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1answer
235 views

Labelling column plot with unit on top in QGIS?

I made a column representation in QGIS, which shows the effects on different points around point 24. Is it possible to label the columns on top with the unit as you are used to from excel? QGIS-...
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1answer
27 views

Clip by extent. FAILURE: No target dataset specified

I am using QGIS 3.10.2 and I am trying to clip a raster layer of the World just to capture Africa. The raster layer was imported from ESRI (https://planet.qgis.org/planet/tag/world%20imagery/) with ...
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0answers
35 views

Raster calculator: using coefficients stored in csv table

I need to calculate an expression over 25 different rasters. The function is the same for all rasters, but the coefficients are raster-specific. I would like to tell PyQGIS to select the relevant ...
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1answer
29 views

Difference model between two raster (DEM) how to show values bigger than and smaller than 0,00

I got to DEM layers over the same area with positive and negative values in them. So I ran a raster calculator raster1-raster2. Now the raster got values with 0,000659 (This should be counted as 0,00,...
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0answers
32 views

QGIS 3.10 layout window: Where is the button to filter the legend by map content?

QGIS 3.10: I'm missing the filter-legend-by-map-content-button below the legend in the layout window. How to filter the legend without this button?
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1answer
47 views

QGIS composer - How to create a table with attributes and style of legend?

Is it possible to create a table in QGIS composer in which I can display organized additional information about items from one layer as well as the symbol of the categorized symbology? For example: ...
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2answers
39 views

Unable to connect WFS datasource with ogr, but works with QGIS

I am accessing some WFS layers via QGIS. I want to download those same layers via ogr. This doesn't work and I can't find why. The WFS URL is https://www.mercator.vlaanderen.be/...
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1answer
43 views

Find and split Multipolygons in spatialite

I have a spatialite table with more than 1100 Polygons. The geometry type in that table is multipolygon. There are only some real Multipolygons inside and I need only polygons. How can I find the ...
4
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1answer
68 views

What is being filtered?

I have a Postgres/postgis table of polygons. When added to QGIS the total feature Count is 64671 in layer tree and attribute table. But the attribute table also says Filtered: 43573. I have not ...
2
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0answers
25 views

Add 'Abc' to styles in legend

Is there a way to add a 'dummy' label to symbols in the legend such as this? The layer it self has a brown/red outline, as shown in the image, and labels are turned on. Since there are a ton of ...
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1answer
47 views

Convert a SQL Server Geometry into PostGIS spatial data with Python and shapely

I'm trying to migrate spatial data from a SQL Server database to a PostGIS database with Python. I need this to be automated since its not just one table, but a lot tables in a lot of databases. I am ...
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1answer
49 views

Python surface plot in QGIS

I'm new in QGIS and I’m having some troubles. I have produced a surface plot in python and I would like to import it in QGIS but I don't know how do that, can anyone help me? P.S. I also have the ...
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0answers
38 views

QGIS cannot open my project

I can't open my project, when I try to Open QGIS it was like "Python error" and when QGIS is open there was "Authentication System: DISABLED. Resources authenticating via the system can not be ...
3
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1answer
29 views

Zonal Histograms in RQGIS3

I would like to calculate zonal histograms (number of raster cells of each type contained in a polygon) using the RQGIS3 package in R. The problem is that I can't seem to find the algorithm name for ...
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0answers
66 views

Using Voronoi.Skeleton in QGIS [duplicate]

My purpose is to make a central line from a polygon. For this I use the skeleton algorithm from a polygon, but I did not manage to get a line. I draw the polygon. I launch the program. It doesn't ...
4
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2answers
70 views

Visualizing signal strength by location

I have a dataset which contains location and signal strength data from a field survey for a radio project I'm working on. An example: lat, lon, signal 34.123, -89.123, 55 34.124, -89.124,...
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1answer
89 views

Finding distance along a line (layer 1) where polygon intersects (layer 2) using QGIS

Layer 1 Line Layer 2 Polygon The polygon will intersect the line in 2 places. E.g. I'd like to attach the 2 distance values along the line to the polygon layer.
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1answer
22 views

Attach features of lines to points

I am trying to calculate the cost of network to homes. In the image i have cable (brown line) between utility boxes(pink/blue points) and home feed (black dash) to the home. I know the cost for each ...
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0answers
31 views

Set a SVG icon for only one feature using PyQGIS

In my QGIS3 Plugin I have a multipolygon layer. I need to set programmatically a SVG icon for a selected feature, without changing the style of the other features. Basically I need to replicate what ...
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0answers
35 views

How to close QGIS polygon without a mouse?

One of my students is using a Windows laptop that does not have physical trackpad buttons; left and right clicks are completed by one and two-finger taps, respectively. The one/two-finger taps work ...
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0answers
38 views

AttributeError: 'NoneType' object has no attribute 'GetFeatureCount' [closed]

I am trying to use the Landscape Vector Overlay function in the LecoS plugin to calculate the amount of various proportions of land cover types (using an ordinary landscape raster) within buffer ...
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2answers
61 views

Displaying the attribute table with one vertical “row” in an Atlas QGIS

I have an attribute table in QGIS with many columns and just one feature. I want to display it in my atlas with the attributes showing vertically, otherwise it is off the page. Is there a way to do ...
4
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1answer
61 views

QGIS make lines with offsets of y and azimuth from source and target coordinates

I'm very new with QGIS and currently stuck with such problem in my work. Maybe some one knows how to help me? I have made two separate layers. Database layer with sites and antennas, containing ...