Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
35,855
questions
2
votes
0
answers
33
views
How to make a projection of a linear layer on an another layer
I'd like to know how to make a projection of a complex linear layer on an another layer, overlapping their geometries perfectly and considering the extremities of lyr_1; using geoprocessing of QGIS. ...
- 639
3
votes
0
answers
45
views
Unavailable layer saved on computer as .txt file in my all projects (.qgz)
I have a problem with all my saved .qgz projects. I always worked with layers in projects only as .txt files, not saving them as shapefile, because I can make changes in .txt files (eg. add more ...
2
votes
1
answer
44
views
Select records by area and update value of CSV
In my little project I have a CSV with more rows than I can count, and I am trying to find a tool that can do the following:
Plot each record on a map using their lat lon coordinates, interactively ...
- 51
1
vote
0
answers
28
views
QGIS - Link derived coordinates to an attribute table
How can I link a field of derived coordinates and attributes to an attribute table? It cannot be copied manually, many lines (100,000).
1
vote
0
answers
41
views
QGIS Add dynamic text in layout from selected feature's attributes
I have a layer called ERVEN with property details from which I select a property/ies. I create an automatic layout from a plugin.
In the layout, I need to add dynamic text. The text will be certain ...
1
vote
0
answers
22
views
Extracting/Filtering of string data based on z Coordinate
I have been supplied with a complex 3D file of a historic mine in .dxf format. The plan is made up of a series "slices", each slice captured at a specific elevation. I have successfully ...
- 21
0
votes
0
answers
22
views
Remodeling of an attribute table in Atlas-Qgis 3.22.4
As part of a project (flood expansion zone inventory [FEZ]) I want to create "Summary sheets" using my attribute table. The latter contains the code of the plots, the owner(s), their ...
- 39
2
votes
0
answers
57
views
Problem with opening .las files in QGIS
For the last few days I tried to open .las Files from my work into QGIS. I have heard that the newest version of QGIS is able to open .las .laz files without any problem. The problem is that the ...
- 29
3
votes
1
answer
103
views
GeoPackage, SQLite: features count but don't exist (QGIS)
GeoPackage is my favorite geo-format but I also have some strange behaviors. One of them: I delete all records/features within a table using QGIS -> Delete Features or SQL statement but there are ...
- 7,653
2
votes
1
answer
13
views
How to set default attribute values on a new line based on overlay_touches/nearest for start_point and end_point
I have 2 tables/layers:
A Point table called "Chambers Used" with names in a field called "Chamber Identifier"
A LineString table called "Ducts Used" including fields &...
- 131
2
votes
1
answer
29
views
"array_agg" function for label in atlas by inserting an expression in QGIS
I want to put a label on the atlas, to know which points correspond to each student for a data survey. That is to show me for each student a list like this --> [252, 254, 271]
In the attributes ...
- 23
2
votes
0
answers
23
views
QGIS 3.14 Set attribute of vector layer based on color of raster layer
I am using QGIS 3.14.
I am working with a raster layer and a vector layer. The Vector layer is a shapefile, and the raster layer is a PDF. I have them over laid on my map and I want to set an ...
- 21
2
votes
1
answer
50
views
Importing text file with coordinates with "N12.345" and "E6.789" as shapefile in QGIS
In our project we have an app that provides data of coordinates with "N" and "E" for Lat and Lon correspondingly. We get the data as Excel and want to open it as shape in QGIS. We ...
0
votes
1
answer
45
views
QGIS defining beginning and the end of the linear element based on point location from the different layer
I have the situation, where I draw the lines from one point to another. They in fact proceed along with the other linear items, but it works well with the snapping tool.
As you can see I must fill up ...
- 3,584
4
votes
1
answer
103
views
Anonymize site locations
I'm putting together some training materials for a workshop on R for spatial data analysis in archaeology, and need to anonymize the true site locations (confidential information) while keeping the ...
- 143
0
votes
0
answers
60
views
QGIS WMS layer alignment with OSM
Please bear with as I'm a complete novice when it comes to GIS and QGIS, so some of the terminology may be incorrect.
I am using QGIS as a WMS client to test my WMS server. I am trying to overlay a ...
- 101
2
votes
0
answers
67
views
ogr2ogr errors: PROJ: proj_create no database context specified, cannot prase CRS, proj.db lacks database.layout.version.major/minor metadata etc
I have a PostgreSQL/PostGIS database that I have been working on and it's generated in a docker container. I access it via PGAdmin to the docker DB or sometimes I create a backup and restore locally ...
- 21
0
votes
1
answer
53
views
How to create boundary (outline) polygon from raster grid (GeoTIFF floating point grid) [duplicate]
I would like to create a vector boundary polygon from a raster(for instance GeoTIFF floating point grid) in a smooth way.
Anyone have a clue about how to use QGIS and/or GDAL?
Input: GeoTIFF floating ...
- 1
1
vote
0
answers
42
views
Change the headlines of a attribute table in QGIS
I would like to change the heading of a column in the attribute table of QGIS.
Originally I had a vector layer linked to an Excel table and so now I have old and new forest locations.
But both columns ...
- 11
0
votes
0
answers
16
views
How to specify the class values for an ENVI .hdr labelled raster
I have this set of an ENVI .hdr Labelled Raster which have the following files:
mosaic
mosaic.hdr
mosaic.aux.xml
The mosaic file is the actual raster while the mosaic.hdr file that comes along is ...
1
vote
0
answers
28
views
QGIS Model Designer: 'Algorithm is not available' and 'NoneType' object has no attribute 'displayName'
I am building a model to automate a process of generating points at street intersections. When I run the model, there is no output. Checking the error logs, I see this:
2022-04-26T10:55:36 WARNING ...
- 21
2
votes
1
answer
54
views
QGIS 3.24.1 - Problem Plugin NTv2 Datum Transformations - A failure in the SSL library occurred (_ssl.c:1129)
I'm trying to use the NTV2 Datum Transformations Plugin, but I'm not able to process it without errors (I'm using Win10). I am trying to use the transformation "[AT] Direct and inverse Vector ...
- 21
4
votes
1
answer
94
views
Adding lines to polygons in QGIS
I'm mapping quick clay risk areas and have extracted areas which could trigger slides (slope > 1:2.5; height (min/max) > 5m). The areas are separated into zones of roughly equal aspect (30 deg), ...
4
votes
2
answers
206
views
Drawing lines that overlap inside the perimeter using QGIS
I want to make a map, with two plots. I want to draw them only with a line along the perimeter of each one, with different colour. My problem is that when the lines overlap, only one colour is showed.
...
- 811
1
vote
1
answer
32
views
Raster slope created in QGIS: values do not exist when imported into R [closed]
I used an ocean bathymetry raster (depth) to create a slope raster in QGIS with the "declividad" raster tool. Besides the fact that I was only able to do this by converting the bathymetry ...
0
votes
0
answers
21
views
Convert 3D vector points to LAS data for use in QGIS
I have a vector layer of points with 3D coordinates and one numerical category attribute. I would like to convert these to a LAS-file which can be visualised in QGIS with the attribute as a component ...
- 2,486
4
votes
3
answers
81
views
Hiding multiple horizontal rows in the attribute table in QGIS
I would like to see only the first 10 of my 150 attributes show up in the attribute table and have the rest 140 attributes "hidden". Is this possible? However, it would have to be possible ...
- 41
1
vote
0
answers
21
views
Is it possible to "copy" one layer from WMS and create another WMS only with this layer automatically?
I'm using Lizmap and QGIS to create WMS service with multiple layers. Now I need to find a way to create WMS containing only one layer that the 'main' WMS contains.
Is there any way to do it without ...
- 11
3
votes
1
answer
49
views
Adjusting size of North Arrow with rotation in QGIS Print Layout
I'm trying to fix the size of my north arrow with 20mm x 20mm. My problem is when my map has a rotation, the arrow is smaller (due to the inner box).
So I'm trying to set the size of my box with:
20*(...
- 600
1
vote
0
answers
33
views
Vector files in QGIS are very badly deformed in different projection systems [duplicate]
I have a vector file of a world map, a shapefile. I wanted to make a map of the world centered on the Pacific Ocean, so I used EPSG:8859 BUT the Arctic and Antarctic regions will undergo severe ...
- 35
0
votes
0
answers
20
views
Tool to find and delete empty images (for tile layers)?
I just generated a tile layer using QMetaTiles for QGIS.
But it renders a lot of empty images: I don't need to upload those ones on my FTP.
Does anyone know a tool that might detect (and delete) those ...
- 187
1
vote
0
answers
17
views
Mapping netCDF file in the right location with different value and location files
I'm looking to work with data from the Sentinel-3 Sat of ESA.
I downloaded data in a zip with multiple netCDF files.
I want to open the data in QGIS in order to visualise it.
I figure out that the ...
- 27
0
votes
0
answers
39
views
Dissolve multiple layers
I want to dissolve over 100 shapefiles into same attributes to eliminate number of features. I was going to merge all the polygon first then dissolve it, but each layer has 10,000 to over 50,000 ...
- 33
1
vote
1
answer
28
views
Simplifying Water Areas in QGIS for Artwork
I am using QGIS to create geographic artwork with topo and water features.
I have downloaded the NHDWaterbody dataset from the USGS. Some of the wetlands are causing me real issues. For example, here ...
- 111
-1
votes
0
answers
37
views
Getting rid of "Text" with no layer and not annotation using QGIS
Not sure how it got there, but I have "Text" sitting on my map. I've turned off every layer but it's still there. I've tried all the annotation tools, but it's not an annotation. It sits at ...
1
vote
0
answers
30
views
Creating QField form where answer for drop-down field opens linked drop-down field [duplicate]
I'm trying to create a qfield form where an answer for one drop-down field determines the next field's drop-down options. Specifically, I want a value map with the options Sedimentary, ...
2
votes
2
answers
51
views
OSGeo4W Install from Local Directory seems to expect Win32 applications
I want to install QGIS 3.18 on a PC running Win7-64bits.
I have manually downloaded all required files (listed in https://download.osgeo.org/osgeo4w/v1/x86_64/setup.ini) from here: https://download....
- 549
3
votes
0
answers
67
views
Selecting and changing fields in QGIS graphical modeler
I am trying to run a model that makes a selection from a refactored and name changed field, and changes the value of the selection.
Refactoring is easy, as is making the selection within the renamed ...
- 31
2
votes
1
answer
37
views
Counting how many unique values each pixel contains across rasters/layers
I am using QGIS.
I have 20 large rasters showing land cover over 20 years (MCD12Q1). Each pixel contains a value between 1 and 17 that corresponds to a land cover class.
I am trying to create a new ...
2
votes
0
answers
37
views
How to join attributes by field value on-the-fly?
I have two spatial (polygon) layers (table 1 and 2), and another non spatial table (table 3).
Table 1 & Table 2 have identical columns but different fields.
Table 1 is edited by user 1 only
Table ...
- 49
0
votes
1
answer
28
views
ogr2ogr convert WFS data, when WFS has password and username
I am trying to use ogr2ogr on a WFS with username and password.
I tried to follow this answer here
Import data from password protected WFS using OGR2OGR
Does anyone have some examples of doing this?
...
- 561
1
vote
0
answers
41
views
Could not find the matplotlib module. Make sure the matplotlib is installed
When I open my QGIS this message is open :
Could not find the matplotlib module. Make sure the matplotlib is
installed.
I am trying to install the matplotlib through OSGeo shell (windows system) but ...
- 11
1
vote
1
answer
35
views
Using QGIS Information tool on WMS Image Service
I'm new to QGIS but with decent ArcGIS experience.
I'm trying to use the information tool in QGIS to interrogate the date an image was taken from a WMS (https://spatial-img.information.qld.gov.au/...
1
vote
0
answers
29
views
Different number of records in gpkg vs. shapefile after join
I'm using pyqgis 3.10.1.and trying do Spatial join with one-to-many option for points and multipolygon. After processing result shows me too low number of records. I save results to geopackage but ...
- 31
1
vote
0
answers
17
views
Delineate valley floor and valley width in SAGA GIS [closed]
How can I delineate valley floor and compute valley width in SAGA GIS?
- 31
2
votes
0
answers
32
views
Why Betweenness Centrality in large networks have negative values?
I use GRASS GIS v.net.centrality to calculate betweenness centrality.
As far as I know there should be values from 0 to (n-1)(n-2) in any given network with n nodes.
However I got lots of negatives (...
- 71
0
votes
0
answers
125
views
QGIS 3.24 on Ubuntu 22.04 issue with SIP Python support is disabled
I'm not able to load any plugin on a freshly installed QGIS 3.24.2 (I step by step followed the documentation available here: https://www.qgis.org/en/site/forusers/alldownloads.html#debian-ubuntu) on ...
- 6,698
2
votes
1
answer
42
views
Given table of coordinates, obtain attribute from GeoTIFF file for given location
I am completely new to GIS, am currently using QGIS to try and accomplish a major feat.
Background: I have a file of over 150,000 property lat/long coordinates that exist in WA & OR (USA). I have ...
- 21
2
votes
1
answer
44
views
QGIS: Layout Manager->Legend->Format numbers
In a layout, I have a legend with concentrations that are very low values with high precision. The preferred option is scientific notation. I employed the recommended expression in Is it possible to ...
1
vote
1
answer
26
views
Creating map through atlas defined by attributes
I am trying to automate the creation of maps using atlas. I have a shapefile with the location of different big cat species in an area of Africe. I want to plot each species on a different map. The ...
- 11