Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
27,258
questions
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29 views
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, ...
0
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0answers
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 ...
3
votes
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 ...
4
votes
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 ...
1
vote
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, ...
-1
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0answers
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 ...
-1
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0answers
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?
0
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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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0answers
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
...
0
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0answers
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 ...
2
votes
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 ...
11
votes
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 ...
2
votes
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
votes
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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
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 ...
0
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0answers
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 ...
0
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0answers
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://...
0
votes
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
votes
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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
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 ...
0
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0answers
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....
1
vote
0answers
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, ...
1
vote
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
votes
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-...
1
vote
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 ...
1
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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 ...
1
vote
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,...
1
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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?
0
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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:
...
2
votes
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/...
1
vote
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
votes
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
votes
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 ...
1
vote
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 ...
0
votes
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 ...
1
vote
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
votes
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 ...
1
vote
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
votes
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,...
0
votes
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.
1
vote
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 ...
0
votes
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 ...
1
vote
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 ...
2
votes
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 ...
5
votes
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
votes
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 ...
