Questions tagged [qgis]

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

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11 views

Raster values change after any kind of operation/calculation in ArcGIS, QGIS, R to -3.402823e+38 and new maximum

I have a single band raster file (.tif) with pixel values indicating the water depth (in meter) of a flooded area. The pixel size is 1m. My general objective is to extract these values for a given ...
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2answers
45 views

Spell Check in QGIS

Does anyone know if QGIS is going to have an in-built spell check as standard in future versions? It is one complaint I get from staff is lack of a spell check. If not has anyone successfully found a ...
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1answer
45 views

Donut shape related to concentric circles in QGIS

I would like to get an area between 10 miles and 20 miles from the center of counties. To do that, I wrote the code and got the following image. But, as you can see, there are some empty points, as ...
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7answers
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Performing Raster Reclassification in QGIS?

Is there a way to perform a reclassify of a raster image in QGIS? In ArcGIS you can do that in Spatial analyst Tools→Reclass→Reclassify Any ideas?
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1answer
22 views

QGIS: Converting a QVariantlist from a GeoJSON to a List with some prefix removed

I have some problem seeming to converting a QVariantList from a GeoJSON file to a list in a new shapefile. Every time I just do the expression "Column" and just put the type of data as List ...
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8 views

SCP Plugin for QGIS 3.10 on Mac

I'm using the semi-automatic classification (SCP) plugin in QGIS on a Mac OS Catalina 10.15.5. I've tried it in multiple versions and I'm having issues with saving files. Whenever I click the Run ...
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2answers
102 views

Issues reprojecting Hydro 1k to WGS84

I have downloaded the Hydro 1k dataset for Africa from the USGS Earth Explorer portal. Rasters are provided as .bil files, and according to the Readme are in Lambert Azimuthal Equal Area projection. ...
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14 views

QGIS export 3d view / vector layers of 3d model to cad/blender friendly format

I am loading vector layers in .gml format that create 3d models on a map. I'd like to save that model out of those layer using either 3d rendered map or other method. Is it possible, and If so, how?
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QGIS: How do I combine/summarize information from several attributes to one specific attribute?

I have a pretty specific question and I dont know how to approach this. I have a polygon layer for subbasins in the Danube area (HydroShed) which also contains information for water discharge. The ...
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32 views

Calculate Percentage population from Vector Grids

I have a vector grids layer of population (shapefile). Each grid represents population in that grid and have the following attributes: Area Population I want to calculate and display the percentages ...
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Naming clipped layer according to the attributes of the mask layer in QGIS

I have calculated the dnbr for a fire season across a whole region, and I've clipped it using a mask. The mask is a layer of ground survey plot locations because I want to find out the dnbr for each ...
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1answer
22 views

Has anybody else experienced having issues opening QGIS or .gqz project files on macs?

I have an old Macbook pro with QGIS 3.10 installed. I have not been able to open any QGIS projects I have saved because of this error -> There is no application set to open the document “test ...
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1answer
33 views

QGIS: Turning a string into “relative” hyperlink

I have a few columns in my shapefile that to refer to certain folders and files (PDF, JPG etc.). Because these are intresting in a form for each object, so that people can open them. I want to make a &...
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1answer
57 views

Displaying map title in PyQGIS

I have the following map but I don't know how to make a title appear on top of it. Any suggestion on how to?
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1answer
169 views

Is there a process that will name files using attributes from the clip layer?

My original file is thousands of points across the US. I would like to create separate files for each state and have them named using the attributes from the clip layer. I have been able to get the ...
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23 views

Extract common area from raster layer in QGIS

I have raster layers of satellite images (4 bands R,G,B and NIR) in GeoTIFF format. These images have been taken by a single satellite and consequent images have a small area of overlap between them. ...
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1answer
237 views

Batch export of layers as individual PNG files in QGIS 3.4?

I have hundreds of layers. I'd like to be able export each one as a PNG. I can do this by selecting one, and going to project, export map to image, calculate from layer -> select layer -> save. Is ...
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12 views

Legend in map atlas anchored to bottom left or bottom right will not correctly reposition in PDF

I submitted this as a bug but I'd like to know if anyone here has experienced or has a solution. In a map atlas, if I anchor a legend to either the bottom left of bottom right and if the legend is set ...
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1answer
2k views

Displaying/opening local TMS with QGIS

I want to display the content of a local TMS (a tile map, stored in a directory structure Z/X/Y.png) in QGIS. This is for quick check and comparison. I am not willing to set WMTS webserver for this ...
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14 views

Save a QGIS project as a “no-setup” package containing the project itself, all the layers loaded, and the layer styles?

In ArcMap, you can do this by saving it as a Map Package. When you open the package, the layers are loaded already and is styled the way you saved it. No setup nor finding of necessary files needed. I'...
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1answer
23 views

Printing Output in PyQGIS Plugin

In developing a PyQGIS plugin, I would like to be able to print out variable values to ensure that my program has the desired functionality. I am aware that I can print messages with something like ...
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1answer
29 views

Documenting workflow and processing in QGIS-project

I want to include a documentation about the steps I undertook to create a QGIS-project to be able to understand how my data was prepared and processed, which steps I performed in QGIS. I'm not sure ...
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1answer
225 views

How to delete vertices with the same direction

I have feature with a big amount of vertices. But these vertices are totally useless and make Qgis editing too slow. Lets look on image with example: These vertices inside of black line I want to ...
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9answers
23k views

Identifying duplicate attributes in field using QGIS?

I have a point shapefile with thousands of points. It has an ID code field that is supposed to be unique. Every now and then the data entry clerk wrongly type the ID creating duplicates. Right now I'm ...
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0answers
97 views

Understandiung difference between TIN interpolation methods Linear and Clough-Toucher of QGIS

I started to study TIN in QGIS and created my first TIN from a point layer with elevation. There are two interpolation methods called Linear and Clough-Tocher that give very different results. Linear ...
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28 views

How is Topographic Position Index calculated?

My understanding of how topographic position index is calculated is: TPI = cell value - (mean of cell values within defined neighborhood) But, I see that Weiss' original poster (http://www.jennessent....
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1answer
214 views

Drawing graticule with GDAL/OGR?

I'm trying to generate a graticule with user-defined range of latitude, longitude, and interval; however, my code only displays one line of latitude and one line of longitude when loading it in QGIS. ...
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1answer
17 views

Missing classes from qgis.core module only in PyCharm's editor

I would like to use PyCharm Community Edition 2020.1.2 x64 on Windows 10 as IDE for writing QGIS plugins. I need to base on old version - QGIS 2.18, so I need python 2.7, qt4, and also core modules ...
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0answers
322 views

QGIS - Topographic Position Index

I am trying to compute the TPI from a raster file (geotiff with elevation data) but when I run the tool it works forever. I have left the PC working over the weekend without any results. The file is ...
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3answers
52 views

Creating inset of the polygon

How to create inset of a polygon? Not just visually but as a new polygon. For example - I have yellow polygon and need to create green one: Looking for solution in QGIS.
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1answer
57 views

QGIS (3.10.7) SAGA tools resulting in “The following layers were not correctly generated.”

I am using QGIS 3.10.7 and want to use SAGA tools. I am using an ASCII file (.asc) with a projected coordinate system - EPSG:26919 - NAD83 / UTM zone 19N - Projected. When attempting to use the tools, ...
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2answers
70 views

Do SAGA tools work on QGIS 3.10.7?

Is anyone successfully using SAGA tools in QGIS 3.10.7? I have downloaded QGIS 3.10.7 on multiple PCs and a Mac. All of them have resulted in the same problem when I try to run SAGA tools. A message ...
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0answers
16 views

TIN interpolation to construct DEM shows strange triangulation

I'm working with QGIS and I am trying to create a DEM starting from a DXF containing the grid of points located at 5m from each other. The following picture shows the points imported: I used a TIN ...
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1answer
28 views

Trouble importing coordinates

I'm having trouble importing coordinates. I have a map over Scandinavia, and I need to import sampling coordinates that I've downloaded. The CRS I'm using is SWEREF99 TM EPSG:3006, and the format I'm ...
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2answers
62 views

How to make the display of a satellite image the same across users?

I have a group of users counting objects in a satellite image. To keep viewing conditions the same I wish each user to have the same display (e.g., the same scale). To do this, I have asked users to ...
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0answers
782 views

KML with raster in QGIS

I have a kml file which displays correctly in Google Earth but only as a bounding box in QGIS . What can I do to see the associated raster image?
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2answers
4k views

Importing kmz/kml into QGIS as raster

I have a .kmz file that I can't load properly into QGIS. I already rename the file as .zip and look into the files inside. I found the .kml text file and an other folder with a .png image (the one ...
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2answers
41 views

Ubuntu 20.04 with QGIS 3.14 (pi) SAGA is missing

After updating to QGIS 3.14 in Ubuntu 20.04, SAGA is not available. The Log Panel (View->Panels->Log Messages) said SAGA didn't load. In the Processing Toolbox, the SAGA category is missing.
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0answers
22 views

QGIS can output shapefiles larger than 2 GB [duplicate]

I have read that shapefiles are limited to 2 GB, yet I have found that QGIS can go beyond that limit. In this case, I was generating contours from DEMs. The output would have been greater than 2 GB, ...
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0answers
26 views

Merge polygons to fixed number of equal attribute size [closed]

I have polygons containing data of 60 parishes. I would like to merge these 60 polygons into larger ones according to the number of people. The overall population is 35 916. I would like join ...
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0answers
31 views

(QGIS) Add 3D geometry to a given point for 3D printing

I was wondering if it's possible to add 3D geometry to a given point. My goal is to 3D print a DEM model and highlight some points from a shapefile with a cilinder or something like that, so I can see ...
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0answers
31 views

Disconnect editingStarted in PyQGIS

I am creating a Plugin, where on addFeature button, first user will get a dialog box to select the type of feature user wants to draw. On the basis of users choice, other editing constraints will get ...
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0answers
16 views

How to integrate a Python Script into Processing Modeler in QGIS

I have a model in QGIS and I've generated a Python Script to calculate the matching between two strings (Levenshtein Distance with the FuzzyWuzzy Package) for one of the OUTPUTS. #####################...
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0answers
20 views

Joining attributes between layers based on proximity of features [duplicate]

In QGIS 3.12 I have a Layer Y that has a specific attribute and my objective is to fill this attribute with information from Layer X regarding the proximity between the features of Layer X and Layer Y....
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0answers
28 views

Enable QGIS Core Plugin with Python Code

Kind of a follow on from this related question: Installing QGIS Plugin with Python code Within QGIS, how using Python can I list the keys of the core plugins and enable/disable them? When listing the ...
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1answer
36 views

Redistribute raster pixel value in underlying polygons

Given a raster layer (e.g 10km resolution) and a vector layer with many features (with finer resolution), is it possible to redistribute the value of each raster pixel in an attribute among the ...
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2answers
126 views

Isochrone along direction map of watershed

I am interested in producing a isochrone map given a raster speed map and a direction map (like the output of r.watershed), but I do not see how to produce it. I have studied r.walk and r.cost wich ...
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0answers
18 views

GetCapabilities to themes.json

We have the QWC2 client installed on our server and it opens correctly in the client with the standard Swiss layers. We have a QGIS WMS Server running with a number of layers. We want to know how to ...
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0answers
14 views

How do I get the layer from a featureSource within a QGIS plugin?

I'm writing a QGIS processing toolbox plugin 3.14 and need to modify its features: So am doing something like this: source = self.parameterAsSource(parameters, 'LAYER', context) features = source....
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0answers
23 views

Weighted Voronoi polygons in QGIS

I want to build weighted Voronoi polygons in QGIS, as in How to draw weighted voronoi polygons (thiessen) from points in QGIS?? but the aforementioned answer and code (https://github.com/HichamZouarhi/...

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