Questions tagged [qgis]

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

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Bluetooth my GPS signal to windows 10 tablet using QGIS

Could anyone tell me how they pair their mobile phone gps to a (windows 10) tablet that can be picked up by qgis live tracking? I have tried a few apps which i believe is broadcasting the gps to my ...
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1answer
180 views

Identify Feature by dragging polygon over datasets using QGIS?

When using ArcGIS Desktop, I often use the Identify tool by clicking and dragging the tool over my data and identifying the features within it. Is there a way to do this in QGIS or is setting the ...
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98 views

Resetting database coordinate reference system in QGIS Midvatten plugin?

When I started building a database in Midvatten I followed the tutorial: https://github.com/jkall/qgis-midvatten-plugin/wiki/Tutorial This tutorial suggests for setting up a new database: "When ...
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25 views

Get value from point layer based on start/end of line layer [duplicate]

I need to get a value from a point table based on the end/start point of a line. This is similar to my question QGIS Field Calculator Aggregation with a intersect query aggregate( layer:= 'Point_Clip'...
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1answer
147 views

Is there a way in QGIS to cluster rather than overlap SVG icons from all layers

I have many layers in QGIS containing points. All layers were added as delimited/csv. PROBLEM: These are points from different layers, I'd like them clustered around the area instead:
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84 views

Clipping raster by feature using GDAL in QGIS?

I have successfully selected the feature from a shapefile (boundary) and intend to use this as a mask to clip the raster map underneath. However, having followed instructions when I open the GDAL > ...
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1answer
61 views

Unable to resize polygons/lines imported from Google Earth PRO Using KML Tools

I imported all my files from Google Earth Pro into QGIS and I need to resize some of the polygons (after agricultural job is done, some of fields get bigger or smaller; from corn we go to soy etc.) ...
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1answer
49 views

How to test for previously joined layers before run a code

I've a function that join two added layers. The code works fine, but now I need to test for previously joined layers before run this function. The function code is right below: def jointables(dict): #...
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3answers
499 views

Merge layers that have different coordinate systems

I need to merge two shapefiles and the issue is that one shapefile has WGS 84 coordinate system and the second OSGB 1936. When I try to do the trick with MMQGIS -> Combine -> Merge layers I get an ...
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1answer
350 views

Using processing algorithm 'native:hublines' in standalone QGIS application

I am trying to make hub lines between two vector files. I succeed manually to do that (in QGIS 3.0) and in a PyQGIS 2.18. But my code doesn't work in PyQGIS 3.0. Here it is: output = '/home/user/...
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2k views

Creating layer from selection in QGIS? [duplicate]

I have a point layer (bus stops), and I want to select the ones that are going to be changed (they have a common attribute to select them). I copy the selection (either ctrl+c or with the menu button) ...
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411 views

Installing Lizmap with PostgreSQL

I've been trying to install the Lizmap webclient. I was following this guide. I've successfully came to the part where I have to set up my config files. I am suspecting the error lies within my ...
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1answer
665 views

Cannot select polygon using QGIS

I've created a polygon from lines in a couple of cases where I'm unable to select the polygon using the standard Select Features button. I am able to select the feature using the Attributes Table, but ...
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1answer
1k views

Classifying slope (flat, slope, steep, very steep) in QGIS? [duplicate]

I want to classify the slope of the DEM data, by dividing the slope by 4 classes: flat, ramps, steep, very steep. How to do this with QGIS?
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129 views

Editing and saving CSV file to use in plugin for QGIS?

For using in a plugin (PS Time Series Viewer), I want to edit a CSV file in the way plugin wants. Somehow I think there's a problem with the CSV file. I would like to tell you all my steps because I ...
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1answer
472 views

Splitting KMZ file into two files using QGIS?

I have a KMZ file that contains about 10,500 features. - My mapping application only allows 10,000 (a google api limit) - So how do I split the KMZ file into two files? - Example, file_A = 5,000 and ...
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1answer
291 views

Problems installing the Astun Technology Loader in Windows 7

I previously asked a question Using OS Mastermap SLDs in QGIS I got several answers suggesting that I use the Astun Technology Loader. There are details on how to do this https://github.com/...
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1answer
421 views

GeoServer & QGIS - Using GeoJSON in a WFS request

I'm trying to load a WFS Layer in QGIS. I requst the data from my GeoServer and would like to import the data as GeoJSON. I can export my data in the layer preview section as GeoJSON. Everything ...
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2answers
283 views

where is the v.transects algorithm in qgis?

I am interested in using the v.transects GRASS command. I am however not yet proficient with using GRASS or python in QGIS environment so I would rather do it the old-fashioned way (i.e using the GUI)....
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1answer
67 views

Batch travel distance calculation in QGIS

How to calculate the walking distance between postcodes and destination in QGIS? I have the following shapefiles: 1 layer containing the destination; 1 layer containing 1,000 postcodes. I've ...
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1answer
484 views

Create an attribute table with coordinates vertices in QGIS

I need to create, in a map layout, an Attribute Table item containing the Map Sheet vertices values in different coordinate reference systems, controlled by the atlas (Coverage Layer = Map sheet), as ...
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2answers
635 views

How can I extract features from a WMS layer in QGIS?

I have a WMS layer in QGIS and I want to select and extract certain features in order to vectorize them and perform clipping with other vector layers. Is there any way of doing this? I don't have ...
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1answer
226 views

Reclassify and combine rasters in QGIS?

I have a vector layer containing watercourse location which I have rasterized. I also have a DEM containing elevation data for the region in which the watercourses are located. I would like to ...
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1answer
70 views

Using r.reclass.area.lesser in QGIS?

I want to reclass small areas in QGIS 2.18, but it seems to fail calling the algorithm in GRASS GIS. The interesting lines from the Log of the tool: ... C:\PROGRA~1\QGIS2~1.18\bin>g.region n=...
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1answer
769 views

Gdal_sieve not working with QGIS?

I'm using the Sieve command within QGIS (Raster > Analysis > Sieve), but when I run the command with any variation of parameters, it completely changes the histogram of my raster data from between -0....
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0answers
270 views

Memory issue? qgis python processing does not complete

I have a simple process to make some edits to all the contour files in a directory. It runs fine on the test of 100 odd files but in a directory with about 500 it stops after about 120 files. Is ...
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1answer
190 views

PostGIS intersect query: Raster footprints of multiple high resolution GeoTIFF's or not? [closed]

I have multiple (381) high resolution GeoTIFF's (2x2 meter resolution, 1 band, 700 MB each) that I somehow want to upload to a PostGIS-server to be able to run ST_intersects or ST_3Dintersects queries ...
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1answer
1k views

Retrieving lost data from QGIS? [closed]

I'm trying to help a friend retrieving QGIS data from a formatted drive. Finding the .qgs project that was saved on the desktop is no problem, but it seems that there is no actual data located in ...
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1answer
215 views

Dealing with geometry that should be geography (bad coordinates)

I'm working on a project with a few publicly available datasets. One of them is from the USGS, it's their prediction of peak ground acceleration in 50 years. Here's a link, and here's what it looks ...
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1answer
210 views

Zonal statistics results in some NULL values in QGIS?

I used zonal statistics through QGIS to assign raster image values to polygons. Here, Raster image has value in range from 0 to 238.567. As a result, some NULL values are assigned to polygons, even ...
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1answer
1k views

QGIS OpenLayers plugin needs to be reloaded

Using QGIS 2.12, I successfully add basemaps via Web > OpenLayers plugin. However, if I save the project (EPSG:3857) and later reopen it, the OpenLayers basemap will not display. As a workaround, ...
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0answers
210 views

Connect to local file or PostGIS layer in field calculator QGIS

I'm trying to make query from field calculator so that it would be possible to connect to PostGIS layer (or local file on computer) and select data according to condition so that use this selection ...
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0answers
34 views

Does QGIS support true circular curves? [duplicate]

As a land surveyor, I often bring cad data into a GIS and create polygon representing parcels. Traditional tools I have for cleaning topology are inappropriate so I am looking for something different ...
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1answer
296 views

Is QGIS Server working like this?

On CentOS 7 I have QGIS Server and QGIS Desktop installed. In QGIS Desktop I created a project with raster and vector data and saved it in a ".qgs" file. Then I copied the file in "/var/www/html/cgi-...
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1answer
58 views

Automatic calculation field based on line modification within QGIS [closed]

I have a polygon layer with every cities in my region. One of the field of this layer is the population of the city. I also have a line layer which represents some bus route I would like to ...
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0answers
731 views

QGIS window size problem [duplicate]

I just installed QGIS 3.2 on a new laptop and the map canvas window and map composer windows are half the normal size, with a grey background making up the remainder of the space. How do I make the ...
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1answer
1k views

QGIS not Printing to PDF [closed]

Simple QGIS 1.8.0 not printing to PDF. Suddenly stopped. Is this an error or something. the resultant PDFs are blank pages. When i file print and use a pdf printer it creates blank docs. when i ...
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1answer
208 views

Dividing polygon and assigning values ​proportionally (population) using QGIS?

I need to split several polygons (census blocks) that contains numerical attributes (population) into smaller blocks, but assigning that data proportionally. For example: if the splitting is made by ...
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2answers
724 views

Zonal stats for two polygon layers: calculate proportion of feature cover within polygons

In order to calculate land cover diversity within defined patches, I need the coverage proportion of each landcover type for each patch. So I am searching for something similar to the zonal stats tool ...
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1answer
234 views

Point connection in QGIS [closed]

I have to connect points to a polygon. I tried to use "points to path" and "point connector" plugins in QGIS, but neither of them are working. For testing, I just drew 4 points and used "points to ...
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1answer
219 views

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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1answer
105 views

Sort selected points by latitude/northing with field calculator

I have bathimetry data in .shp format. The points (picture below shows one of multiple groups/profiles) do not have ID numbers and are randomly dispersed through the attribute table. I have selected ...
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2answers
274 views

Adding two vector shapefiles together (one on top of the other) in QGIS [closed]

I understand how to merge two vector shapefiles together but I don't know how to layer one layer on top of another one and export it to make it permanent? I would like to add the GreaterMan shapefile ...
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2answers
199 views

How to open a layer in QGIS from another application?

Let's say I have some metadata about a layer stored in some custom application, and I would like to open or view the layer in QGIS. What, if any, are my options? Edit: formats include shp, wms, ...
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1answer
504 views

Adding multiple layer on Map Canvas using pyqgis

I am facing issues on adding Multiple layer in Qgis3.0. I tried below code but its not working. I am unable to detect what wrong since its not giving error. Both Layers are valid, but cant be added ...
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1answer
929 views

Nearest neighbor analysis not showing results

I'm trying to do a nearest neighbour analysis on fish shoals distribution. I go to Vector > Analysis Tools > Nearest neighbour analysis. I choose the appropriate layer and when I hit ok the black ...
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1answer
422 views

Calculating area under each polygon in QGIS [duplicate]

I would like to know how to calculate the area of the vector layer (red in the photo) under each polygon (white square in the photo). The red layer has the area (km2) in its attributes. But what I ...
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1answer
251 views

How to add a buffer in QGIS that updates itself [duplicate]

I wish to add a buffer into project that will update the buffer fields when new points/ polygons are added into the project
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1answer
2k views

Receiving GDAL Clipper Error from QGIS? [duplicate]

I realise there has been quite a lot of discussion on this topic and have already read through the suggestions on this forum of how to rectify this problem, but still nothing has worked. I am ...
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1answer
276 views

Is possible to create a new column of QGIS?

I want to create a new column according to the column A & column B. Column A 1 2 3 Column B A B C New Column 1:A 2:B 3:C How can I do that in QGIS?