Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
6,459
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Elevation profile 10 km each side of line
How can I get an elevation profile for a band of terrain?
The highest elevation within 10 km (on each side of the defined line) should be taken into account.
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3
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How to Create a Grid Inside a Polygon that is Oriented with the Longest Side?
I have been using a process called "Create Polygon Graticule" to create a grid within a polygon with assigned row and column attributes. It is a SAGA tool which I have been running in QGIS. It ...
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Moving points onto lines (~neighborhood)
I do have two vector layer, of which
one is a point layer based on "events" by remote sensing
and the second one is a line layer from local research.
In my case these are earthquakes and tectonic ...
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3
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Aligning multiple points to line in QGIS?
I would like to align multiple points to a line, or lines within a layer, using a specified tolerance or buffer around the line objects. Please refer to the sample sketch attached.
For the sake of ...
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Difference between quotation marks ('single' vs "double") in QGIS
I am confused concerning the quotation marks syntax ('single' vs "double") in QGIS.
I know something about the quotation marks and the way they are applied in Python scripting (i.e. comments,...
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Making automatic updated date and time field in QGIS?
I want to make a date and time updated field as I edit an attribute field in this format yyyy-mm-dd 00:00:00 (= 2016-05-08 11:04:00) - my local date/time. The data is in a QGIS 2.14 shapefile and ...
- 1,135
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QGIS expression with overlay-fuction: filter-condition based on comparison of attributes from two layers
In QGIS 3.18, I have two point layers: layer_1 with attribute id_1 and layer_2 with id_2. I want to use the overlay_nearest function: overlay_nearest(layer[,expression][,filter][,limit=1][,...
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How to move layers in the Layer Order Panel using PyQGIS?
Related to the following question but looking for a PyQGIS method:
QGIS Layer Order Panel - add layers at top of layer order
The following is a simple setup containing a group with three layers.
...
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11
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1
answer
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How to automatically populate fields instantly?
I am looking to create an attribute table where the first field is a drop-down menu (I have achieved this by using the 'value map' edit widget), but I'm struggling to find a method for the next part;
...
- 448
11
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3
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Rotating a vector layer in QGIS with qgsAffine (or other method)?
I would like to rotate a set of vector points in QGIS an arbitrary number of degrees around a central point (or arbitrary point).
This is similar to a recent question about creating a regular grid; ...
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Getting image pop ups in QGIS
I have a map of an area and georeferenced photos. I need to be able to bring the pictures as points and then be able to click at a certain point and an image pop up.
I have revisited this issue, i ...
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1
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How to reproject a raster file in QGIS with datum transformation?
I want to reproject a tiff raster file from projection A (ETRS89/UTM Zone 32) to projection B (DHDN/Gauss-Kruger zone 2). The two projections have a different datum so I have to use a datum ...
- 6,219
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Converting point layer to raster grid that shows frequency of points per cell uisng QGIS
I have a point layer that shows the distribution of a species.
Is it possible in QGIS to convert this point layer to a raster grid in which the value of each cell corresponds with the amount of ...
- 165
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QGIS 2.14.1 LAStools install error: "wrong value for parameter 'Msys folder'..."
I went to step 4 from How to install LAStools toolbox in QGIS guide and extracted LAStools to my C drive and just made the folder there.
I can't do step 8 because it seems to already be in "advanced ...
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Converting/using ArcGIS *.style file for/in QGIS (QML or SLD)?
I have downloaded a dataset from a government organisation. it comes with a .style file.
I use QGIS 1.8 on windows 7.
Is there a way to use the .style file as a qml or sld? I have tried simply ...
- 2,575
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How to display special German characters "ÄÜÖß" in a map?
I have a shapefile with names for Regions. These don't seem to contain special characters "Ä", "Ü", "Ö", "ß" but ugly hieroglyphs.
What can I do to display them correctly. If I import the shape as ...
- 2,311
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3
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How to create contour lines from point data using QGIS?
I'm using QGIS 2.4.0 and I have a shapefile of points with elevation data and X and Y coordinates. I'm using windows 7 OS.
The idea is to create a contour line SHP using my point data.
My question ...
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1
answer
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Unique constraint failed error when saving GeoPackage in QGIS
In QGIS, when using Processing tools, the temporary output layer in many cases cannot be saved as Geopackage. This happens for example when using "Explode lines" or "Multipart to Single ...
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Representing uneven tree canopy spread around point in QGIS
I am trying to make an attribute to show the uneven spread of the crown of a tree using the four cardinal points. I can use a buffer to show one feature, in this case a root protection area. But I ...
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1
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Counting points in polygons using QGIS
I want to count points (1000 of students home) in district polygons with Qgis 2.16. I didn't find the tool in the analysis tools plugin.
Is there another plugin or method I could use to perform this ...
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Combining multiple overlapping rasters - retain maximum value?
I have 40 overlapping raster grids (derived from flood modelling software) that I want to combine in such a way so as to retain only the maximum value in any of the given rasters at each grid location,...
- 437
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Changing to alternate label if first label does not fit in QGIS?
I'm trying to create a map to print out and the size of my polygons varies greatly. As this will be a reference map I need to label every polygon, but some of the names will not fit in the polygon. In ...
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QGis Save Raster as Rendered Image
In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image".
When selecting the Rendered ...
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2
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Using grid files (*.gsb) in QGIS
When opening a data source in EPSG:25832 in a project with crs set to EPSG:31468 I am prompted to select a datum transformation (e.g. +nadgrids=BETA2007.gsb)
The nationwide standardized grid file for ...
- 14.6k
9
votes
2
answers
12k
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Exporting DEM-derived rasters to CSV from QGIS?
I have been able to import into QGIS a set of raster topographic maps and the associated DEM raster maps. It registered the two for me. From there I have calculated the associated slope raster map. ...
- 273
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2
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Define custom CRS in WKT from point and angle
I'm trying to define a custom CRS using the WKT Syntax. However when I do the projection I'm off by about 2km.
Here is my rotation point.
Local X and Y:
X: 4635.396 Y: 2397.085
MGA94 Zone50:
x: ...
- 539
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votes
1
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Can't export geometry generator styling to DXF - alternatives?
I've been using QGIS' wonderful geometry generator to dynamically generate root protection zones and crown areas for some tree inventories I've been working on. It's been a massive time saver.
...
- 12.5k
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Seeking open source alternative to ArcGIS Desktop Integrate tool [closed]
I need to snap about 1000 lines in one layer to the lines in another layer (there are about 5000 lines in the second layer). The lines to be snapped are about 15 map units away from the base layer ...
- 79
7
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2
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4k
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How do I split polygons into line segments?
How can I split my polygon file into "segements"? The lines should be broken up like this picture shows:
- 7,097
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1
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How to create a point along a line given distance
I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
- 1,772
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3
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Unable to stylize raster data as pseudocolor render type on MAC OSX
In a raster layer's Style Properties, I can choose pseudocolor render type, and choose a color ramp and classify the raster.
However, when I click the 'Apply' button, or click 'OK', the ...
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2
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Colouring areas between (vector) contours?
Is it possible to colour areas between (vector) contours without making it a DEM first?
Joshdoe seems to have done so in Create filled contour map with GRASS but does not say how.
- 1,079
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votes
4
answers
8k
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Workflow for creating line features between two coordinate pairs in QGIS
I have a table of stream reaches with XY coordinates for their respective tops and bottoms.
I'd like to convert the table to a feature, using the XY coordinates as the endpoints of the line.
Any ...
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How to add links to PDFs in a Shapefile?
I want an attribute in a shapefile named "Link" to add.
The works are all fine but then I would like to add a link in my directory.
This link accesses a PDF. Now, this PDF is not shown.
Is there ...
- 603
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votes
1
answer
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Activating 'missing' standard GRASS utilities in QGIS Processing toolbox
I have been using QGIS and Grass for ages and while I've noticed this issue before, I've not been bothered by it until now. It is (hopefully) a bit of a noob question but when I open GRASS in the ...
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Importing 3D DXF file into QGIS with z information as attribute value?
I have a dxf file of 3d contours. after import it does have only layer,x,y attribute and doesn't have Z attribute.
How can I provide Z attribute to create a TIN file?
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3
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QGIS Raster calculator - if statement
I'm fairly new to QGIS, but I'm getting the hang of it. I have two layers - one DEM and one raster made from shape file (Buildings), but need one with higher Elevation where the buildings are for ...
- 41
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4
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Installing QGIS on Ubuntu 14.04?
Following the QGIS installation guide I have tried both UbuntuGIS and QGIS stable, but both fail with the error message:
The following packages have unmet dependencies:
python-qgis : Depends: python-...
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votes
3
answers
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Calculating slope in percentage with QGIS
I'm working with QGIS, v. 2.0.1. I have several soil types. They are (amongst others) described with slope indications. I already calculated the slope from the DTM in degrees, but as description of ...
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1
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Setting QGIS Python version?
I have brewed python 2.7.3 onto my Mac (Lion), and installed shapely via pip install shapely. The Polygonizer plugin, however, does not find the shapely library. I see when QGIS loads a Python console,...
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votes
1
answer
806
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Anti-aliased rasterization of vectors in QGIS?
I have some polygons that I want to rasterize, but in a fairly low-resolution grid (cell size 250x250m). The raster values of the area inside the polygons should normally have the same value (100), ...
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1
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Sorting grid cells in fishnet grid by location and number using QGIS?
I am using QGIS 3.2.0 on a Mac (and also have QGIS 2), and I have a fishnet grid (probably created in Arc) that comprises of nearly 2 million grid cells. As a result, every change I make to the ...
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votes
5
answers
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Renaming attributes/fields in shapefile attribute table using QGIS
I would like to rename some fields in my attribute table:
Like rename "XRF_N3"in something else. It seems quite a easy issue but I don't find any information about how can I do that.
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votes
8
answers
81k
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Сreating polygons with straight lines and right angles in QGIS
When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles?
For instance, how do I create a perfect square or ...
- 3,157
48
votes
5
answers
25k
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Smoothing DEM using GRASS?
I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough because the area is near flat and the DEM is 90m in ...
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votes
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answers
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Ignoring invalid input features with Intersection tool in QGIS?
In QGIS 2.18, when I used the Vector > Geoprocessing Tools > Intersection tool, I was able to check an option which said "Ignore NULL geometries [optional]".
Now I've downloaded QGIS 3.2 and that ...
- 2,509
36
votes
3
answers
42k
views
Handling multiple map frames with different layers in one print layout?
Often I need two (or more) map frames in map layout to present different data next to each other. It is easy to make multiple map frames in QGIS Print Composer. BUT...
It is in the nature of my work ...
- 9,744
30
votes
3
answers
39k
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Opening GeoJSON file with mixed geometries in QGIS?
If I have a GEOJson file, for example a file named test.js with inside the following:
{ "type": "FeatureCollection",
"features": [
{ "type": "Feature",
"geometry": {"type": "Point", "coordinates": [...
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Grouping and counting attribute data in QGIS
I want to group and count features with the same code attribute value.
I can classify the data and enable feature count in the layer list but I cannot get counts in the attribute table.
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8
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27k
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Getting list of distinct values from shapefile field using QGIS
I have a shapefile whose features I can filter by specifying a where clause in the query dialogue. F.x. I have a field named "city_name" and by stating "city_name" = 'London' in ...
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