Questions tagged [qgis]

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

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29 views

How QGIS shows “EPSG:4326 - WGS 84 - Geographic” for the GeoTIFF file's CRS, and how to reproduce it in GDAL and Python?

I have a GeoTIFF file (named avhrr.tif), and tried detect it's CRS in Python and gdal and compare it's values with that in QGIS. Here is a screenshot that is taken from the QGIS: Here is the code ...
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1answer
27 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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12 views

Correcting MODIS band stripes [closed]

I am trying to generate the NDVI and NDWI in order to calculate the NDDI based on MODIS imagery. For this, I am using the bands 1,2 and 7. While working with the data, I have remarked that the band 7 ...
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3answers
45 views

Where to find the applied transformation method and accuracy information when reprojecting a layer in QGIS?

When I load two layers with different CRS I'm prompted to choose a transformation method and there is a column indicating the accuracy (see image 1). I would like to know where the information as part ...
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34 views

QGIS. How to generate XYZ tiles (mbtiles) from Web (XYZ) Layer for limited by boundaries area?

I'm using QGIS v. 3.14 and want to create mbtiles database on the base of XYZ layers (from QuickMapServices, for example, OSM Standart) for a limited area on the map. That means an only selected area ...
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10 views

QGIS Modeler: Layer Rename does not output

I am currently in the creating a process in my QGIS model builder where I am trying to rename a finished process layer based on some best practice rules. Here is the model: Now here is the expression ...
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1answer
38 views

QGIS how can I open my own Map into QGIS (not an Open Street Map)?

I am working on a project, that shows a list of german instituts financed by a treaty in the year 1949. Therefore I need to work with an historical map of this year, which I have. So my question is, ...
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34 views

QGIS how to select a set of features in field calculator expression

I try to connect one feature from a polygon layer to many in a point layer, using geometry generator and expression calculator in the polygon layer. If I can connect 1 polygon to all the points, ...
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0answers
18 views

Customize header for coordinates in CSV export

Is it possible to customize the header for csv export from QGIS? I use "Export -> Save Features as" to create a csv with the names and coordinates for a list of points. The default when ...
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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
30 views

Raster artefacts after saving to GeoTIFF in QGIS

When processing DEMs created using downloaded SRTM data (initially HGT files) I produce a nice-looking product; however, saving this as a GeoTIFF creates square artefacts which are plain to see (and ...
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1answer
26 views

Different number of grid cells between years when using a grid layer to look at area of land cover change over time

My goal is to calculate the area of mangrove cover (vector layer) per grid cell (vector layer) over time (yearly), to determine land cover change. I have tried two ways so far. Initially I wanted to ...
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32 views

Get point layer from CSV with coordinates in meters [closed]

QGIS 3.10. Project in WGS 84/UTM zone 41N. Trying to create new point layer from CSV file, where coordinates for X and Y are given in meters (MSK-66 zone 1 - one of local CRS for Russia based on Gauss-...
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20 views

How to uninstall QGIS 3.8 from MacOS in a clean way?

I have two installations of QGIS, 3.14 and 3.8, I want to uninstall 3.8. What is the proper way to do it? Do these instructions also apply to this newer version? The following are the paths that the ...
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1answer
68 views

How to get real lat lon values (degrees) of line geometry in QGIS?

I have a line layer in QGIS. The project CRS is WGS84 (4326) and the layer CRS too. The goal is to have the coordinates of the line nodes in a csv - one row/field per line. Now I tried copy/paste of ...
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1answer
29 views

Can't get array_foreach function working

I have a STRING field with values. When I want to apply some additional text after each value using an array function, I get the text added to the end of the whole initial string instead of each value....
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34 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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28 views

How to interpret the Maximum flow path length raster, from the SAGA Maximum flow path length tool

Does anyone know how to interpret the Maximum flow path length raster, after running the SAGA Maximum flow path length tool? I have used this tool and received a raster but I'm not sure how I can get ...
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14 views

What's the role Qwidget and Qlayout in the QGIS interface?

I use miniconda3 to manage my software installations, including QGIS, so I can use packages like geopandas easily in the QGIS python console. Lately however, when I open qgis from the command line ...
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0answers
36 views

QGIS 2.14.9 refuses to open GeoPackage file

I tried to open in QGIS 2.14.9 a .gpkg file but this action resulted in an error message stating that the file is not a valid or recognised data source. However, QGIS includes support for the ...
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2answers
29 views

Callout lines grouping on Lables with the same name

I am using callout lines to take the label away from the point to make my maps easier to read. Running QGIS 3.4.11 I am using this expression: make_line( make_point($x, $y), make_point( "...
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2answers
49 views

Merging attributes of point features at same location

I have a CSV-file with all the facilities in an area, some sites have multiple facilities so at some locations there will be multiple points e.g. sports hall and swimming pool. Is there a way to join ...
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36 views

Creating a Python loop to add up automatically generated rasters on QGIS 3

I'm creating a QGIS 3 program that extracts flow paths from a DTM, then slightly modifies the DTM to extract new flow paths that I want to add to the previous flow path raster. I have used the ...
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0answers
13 views

QGIS SCP doesn't stack all bands for Sentinel 2

I've been following various tutorials to try and stack and then eventually classify images from Sentinel 2, but after downloading the images and running the band set tool, it simply only stacks 4 ...
2
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1answer
47 views

“Move feature” for points, manually moving a set of points with the mouse in QGIS

For moving a feature, the process is to edit the layer, use the "move feature" button, then drag and drop the feature. I have a point shapefile layer, and would like to move a set of points. ...
2
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1answer
36 views

How can I render a composite (multi-band) raster in true color in QGIS?

I have gone through most QGIS troubleshooting steps in the GIS stack exchange but have not found a solution. I have imported a composite multi-band spectral GEOTIFF raster as part of the Hansen Global ...
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0answers
17 views

Change GeoPandas column value from PostGIS query

I have some QGIS layers and I am performing some spatial queries with them using GeoPandas. I'm using psycopg2 to make a connection to a local PostgreSQL/PostGIS database. Then I use the read_postgis()...
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0answers
40 views

How to store metadata in PostGIS [closed]

How can I include metadata for my data in PostGIS? I want to have the associated metadata for my shapefiles saved alongside the data in my database so that I can connect the database to QGIS and ...
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1answer
54 views

In QGIS, how to input & select multiple values from GUI? (without repetitive OR, OR, OR)

In QGIS, most likely from the SELECT FEATURES BY VALUE...(F3) or SELECT FEATURES BY EXPRESSION...(CTRL-F3), what is the simplest most flexible way to put in multiple values and have QGIS show that ...
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1answer
28 views

Installing QGIS 3.14 on Mac OS 10.15.5

I have installed Python 3.6.8 and am attempting to run QGIS 3.14. I get this message, which doesn't show in any existing questions I could find: Should I try an earlier version of QGIS? Tried 3.10 ...
2
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1answer
31 views

Extract points automatically from GeoPDF

I have a GeoPDF file which have some small icons (e.g. triangle, small man, small boat, circle, and so on..). I need to extract these icons in a point shapefile - automatically. Is there any plugin or ...
3
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1answer
73 views

Looking for a deep learning platform for image recognition, preferably in QGIS [closed]

As part of a project I am working on, I am collecting an image training dataset consisting of various images of agricultural fields (details spared for confidentiality). The end goal of the project is ...
1
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1answer
44 views

Sorting Points after distance from start point

Currently, I am working in QGIS to draw and plan grids. For different reasons I need to sort my pole layer (points) in the order that they run along with a cable layer (lines) with the same "...
1
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2answers
42 views

how to convert the geometry of the elements of my table to move it from one srid system to another?

I have a table containing a column geom loaded from a shape file which was defined in lambert II system (27582), but when I loaded it I specified that I want to work in lambert 93 (2154). ...
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0answers
20 views

Data type gets converted from “qlonglong” to “int” when creating Virtual Layer

I have a source layer with ID column as qlonglong. When I execute a query in DB Manager the types seems correctly preserved. The problem is that if I "Load as New Layer" the resulting ...
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0answers
41 views

How to visualise generic geometry column from SpatiaLite database in QGIS

I have a SpatiaLite database with various tables. One is a table called Geometries that has a geometry column which is defined as a generic Geometry column - that is, not POINT or POLYGON or anything, ...
2
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0answers
21 views

Generating TIN and/or DTM from point feature data

I have parameter data that is linked to points within a polygon area. I am trying to find ways of creating an interpolated layer for the extent of the polygon within which the points are located as ...
5
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1answer
69 views

Label direction check

I want to visualize direction of river's course by an arrow placed next to the river's name label. I have an idea to place the blue arrow as a text in front of my label or at the end of my label, but ...
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0answers
12 views

QGIS 3.10 drop-drown list (value relation)

I am using QGIS 3.10. I created a field with a drop-drown list of 10 country names (using an imported csv file) . Is there an option to add a country that does not inculded in the list manually ...
5
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1answer
86 views

Blending features in QGIS: Approximating road edges for map render

I'm having trouble getting the right render for the tertiary roads and service roads look in my map render. I'm trying to get road edges like in the old USGS topo maps: Notice how the road interior ...
5
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3answers
683 views

Creating all possible line segments between all points

I want to connect all points in a point feature with every possible line segment using QGIS. For example, how a pentagon has five points with ten line segments connecting them all to form a pentagram ...
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1answer
37 views

QGIS points disappear after changing CSV file location, changing data source doesn't help

I moved my database and shape files, and wanted to relink them to my QGIS project. The shape file worked fine, but the CSV file wasn't reloading properly no matter what I tried. I could see the fields ...
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0answers
17 views

Preventing loss of detail using “Clip Raster by Mask Layer” QGIS

I am using a raster file of satellite imagry as input for a 'Clip Raster by Mask Layer' process and a shape file polygon as my mask layer. Each time I run the process the output clipped layer is ...
3
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2answers
73 views

Setting QField for 1:n photos

I'm using QGIS 3.12 on Win10 x64. I'm trying to configure QField for 1:n photos. I have a point layer representing trees, and I want to be able to add multiple photos to that pt. I have set up as ...
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0answers
38 views

Converting US Flood Maps from .kml to .shp

I am trying to obtain the flood maps for the United States (base flood elevation and 500-year flood). They are available in .kmz format from https://hazards.fema.gov/femaportal/wps/portal/...
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0answers
45 views

Generating similar random points in QGIS

I have data (Lat, Lon) of 32 buildings, and their plot in QGIS is given below in red dots. Now based on the calculated mean distance (Nearest neighbor analysis) between these points, I want to ...
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0answers
24 views

Rasterize failes in QGIS 3.8

I'm trying to rasterize a polygon layer which has two columns : id and code. I would like each polygon to get value according to the code field. I have used the tool rasterize from the raster menu ...
2
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2answers
43 views

Writing a number if another field is not null in QGIS Table

I am trying to make a condition in a new column that if there is a value in another column, a number will be filled accordingly For example Here's the table If there is a value in "watt_3" ...
7
votes
1answer
133 views

QGIS: Is there a way to make the “Python Console” a separate window?

QGIS 3.10; Ubuntu 18.04 When Plugins->PythonConsole is accessed, it opens as a panel, changing the shape of the map canvas. Can it be a separate window instead? Alternatively, is there a way to run ...
0
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1answer
18 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 ...