Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
25,707
questions
-1
votes
0answers
12 views
How to users upload shapefile into PostGIS from HTML page? [on hold]
I am learning the interaction between server and client. I develop a site to publish GIS data in the web. Here, I used PostGIS, GeoServer and OpenLayers. Now, I try to add some extra features in the ...
3
votes
1answer
24 views
Adding parameters to SQL layers?
I have a SQL-Layer that is defined by the following statement:
select b.id,
b.description,
b.is_event,
geodesic_buffer(b.location_point, 3000)
from bus_stop b
where b.event_id = ...
1
vote
1answer
42 views
Retaining ruler when digitising in QGIS?
I just switched from QGIS 3.4.4 to 3.8, and now when I am digitising or editing nodes, the ruler/measuring disappears when I go/click to digitise a shape or edit a node.
I would like to keep my ...
1
vote
2answers
24 views
Launch bat. for QGIS 3 python not working
I'm trying to build a launch.bat for qgis 3 python. I would want to run python via batch file but I get an error 'no module named processing'
Launch.bat:
@ECHO OFF
set OSGEO4W_ROOT=C:\OSGeo4W64
@...
0
votes
1answer
15 views
How to set CRS on OpenStreetMap? V. 3.8
I am completely new to QGIS and have a basic wuestion,
I am trying to create a map with OpenStreetMap and set it to a specific coordinate system. The problem is that when I set the CRS the map ...
0
votes
1answer
14 views
How to display a Layer Group in QGIS Server with WFS
I want to display layers with QQgis server, but the group layer doesn't get displayed, instead I get a bad request response from the server :
the request : http://myserver/cgi-bin/91589/qgis_mapserv....
0
votes
0answers
34 views
Counting points in polygon containing holes using QGIS?
Basically, I have these area (part of a bigger map) containing many holes (e.g. lakes) I have thrown on the map some 1000 random points and I want now to count those that fall in that area. I already ...
3
votes
1answer
52 views
Cleaning linestrings created from points in PostGIS/QGIS
Can someone please explain the steps to take in order to eliminate the parts of these linestrings which jump across large distances (not along with the road network)?
They were created from GPS ...
1
vote
0answers
22 views
Loading RGB legend for vector layer from text file using QGIS?
I have a shapefile with one field containing a code for geological unit. I don't have ArcGIS Desktop l and therefore cannot access the layer file. However, from the source, I obtained a text file ...
2
votes
1answer
32 views
Moving a memory layer in the TOC using PyQGIS
I've got a layer (difflayer) that has been created in memory. Basically, all the layers I've got in this project are in memory and the layer creation/manipulation is all being handled via a plugin.
...
0
votes
1answer
24 views
Error in catchment delineation process [on hold]
While delineating catchment in QGIS using Upslope Area, error:could not create index insufficient memory prompted and software got hang again and again. What should I do?
1
vote
1answer
24 views
Translating and renaming attributes from one layer to another
I have two shapefiles, one that contains data from our Corporate GIS system and another that I want to import into a software model.
I want to select a subset of the Corporate GIS data (for instance ...
0
votes
0answers
18 views
Combine duplicate geometries into single records with v.clean in QGIS 3.6
I have a points file that contains multiple duplicate geometries. I am using the QGIS "Processing Modeller" to clean up data, and want to identify duplicate point geometries and combine so that I ...
2
votes
1answer
38 views
Displaying Bing Maps WMS in QGIS?
I am trying to display my bing map raster tiles in QGIS. I am using an HTML file like this, except with my own raster tiles, as described in WMS Tile Layer Example.
My own raster tiles don't have a ...
3
votes
2answers
70 views
Creating raster where each cell records distance to sea?
I want to create a raster with a 25 metre × 25 metre resolution, where each cell contains the distance to the nearest coastline, as calculated from the center of the cell. To do this, all I have is a ...
1
vote
1answer
31 views
QGIS - Disable ability to download plugins for unauthorized users?
In QGIS desktop, is there a way to disable the ability for unauthorized users to download plugins? Is it possible to change the settings so that the "Manage and Install Plugins" menu item is not ...
1
vote
1answer
39 views
Raster TIFF file does not project onto QGIS basemap correctly
Forgive me if this is a simple fix, I am new to QGIS 3.8. I have a .tif file that when opened into QGIS is projected on the (0,0) lat/long coordinate of the base map and is very small. I have ...
1
vote
0answers
30 views
Is there a tool to cut a polygon with the outline of a raster layer?
I would like my polygon layer to be cut into two where the end of the raster layer meets the polygon, is it possible? I've tried to polygonize my raster layer, but that doesn't seem to work. Any ...
0
votes
0answers
12 views
Connect MS SQL Database with QGIS Server fails
We have a QGIS Project (2.14) which should be pubished with QGIS Server on a Linux system (debian). On Windows the MS SQL Server data is visible, but with QGIS Server (2.14) the layers from the MS SQL ...
1
vote
1answer
19 views
Check error polyline in QGIS
I am working with topology checker in QGIS 2.18 to check error overshoot, undershoot , but it show all error, so I got many difficult in fix error.
Is there any tool the same with topology checker to ...
1
vote
0answers
28 views
Extract borders from country polygons
I'm trying to convert a polygon GeoJSON of countries into a line layer that contains only the borders. It should not contain the edges of the polygons that border the ocean (in my polygon dataset, ...
0
votes
0answers
17 views
Connecting QGIS to Oracle?
I am using QGIS 3.8 MacOS.
I know that prior releases of QGIS (2.x releases) did not include drivers to connect to Oracle databases, and one would need to compile QGIS themselves with the proper ...
-1
votes
0answers
14 views
Creating TIN from ASCII files containing coordinate definitions in QGIS
In Arc GIS you can create a TIN from ASCII files with coordinates. Is there an equivalent in QGIS 3?
2
votes
0answers
28 views
Discrete color ramp in QGIS
This seems basic but I am new to QGIS and I can't find how to do it. I have three shape files each with the same attribute. Each shape file is imported into its own layer. Each shape file has ...
1
vote
0answers
24 views
PyQGIS ogr provider not Found
I using PyQGIS in my python application，My program couldn't find org provider and failed to create layer.
My code and environment are as follows.
The env:
The Code:
from qgis.PyQt.QtCore import Qt
...
2
votes
0answers
11 views
Making informative legend for Kernel Density Estimate in QGIS?
I have used heatmap (kernel density estimation) in QGIS 3.0.1 to make a heatmap of boat counts.
In my point data-each point is one boat.
Then, in my kernel, I have used a 500m radius, with 500m pixel ...
1
vote
0answers
27 views
QGIS: Authentication System: Resources
I tried to delete and redownload QGIS 3.8 and now I can not make new projects on QGIS because of this error message:
Authentication System: DISABLED. Resources authenticating via the system can not ...
0
votes
1answer
34 views
Importing GeoJSON File
I am dragging and dropping this GeoJSON file into QGIS but for some reason I cannot reproject it from WGS 84 (EPSG:4326). It remains at the original LAT/LONG even in a new project where UTMs are ...
2
votes
0answers
20 views
Issues synchronizing QField into PostGIS
I'm having issues synchronizing my QField project into a PostGIS database.
Nothing is synchronized, and I have the following error in the PostgreSQL logs:
2019-08-29 13:06:34 HST INSTRUCTION : ...
2
votes
0answers
42 views
How to create a filter expression from selection QGIS 3.6.3
I need to create a filter expression to filter only the selected polygons in a layer. Yes I know I can save the selected elements to a new layer but this solution is not suitable for me.
I managed to ...
4
votes
0answers
21 views
Difference between merge and create virtual raster
I have the DEM of a defined region that has been split into sub-DEM with a resolution of 1 km x 1 km. When I merge the sub-DEM to create a single DEM (Raster -> Miscellaneous -> Merge), the overall ...
1
vote
0answers
16 views
How to update or uninstall new “All-In-One” QGIS macOS packages
Recently new "All-In-One" QGIS packages for macOS have been released. This new packages make installation very simple but inside the .dmg file I have not found any readme file for uninstalling or ...
1
vote
1answer
39 views
Create QML Widget with a picture in Attributes Form
I would like a Qmlwidget in the Attributes Form to show a picture.
So far I have created the basic qml for a blue rectangle:
import QtQuick 2.0
Rectangle {
width: 100
height: 100
color: "...
0
votes
0answers
33 views
Distance matrix only for a specific rule [QGIS]
I am having a hard time using distance matrix vector tool in QGIS for a specific need.
I know you need to have two different point layers in order to get a distance matrix, so far so good.
But as I ...
2
votes
0answers
45 views
QGIS large map with high resolution details
I am trying to make a map that shows a very large region of southern Ontario but i would like to be able to zoom in on the map once it is created to see fine details such as the names of much smaller ...
0
votes
0answers
20 views
How to come up with Radius maps in qgis [duplicate]
I am relatively new to qgis. I have GPS coordinates of two types of sites in csv format, (water point site and sanitation site). I wanted to find out if it is possible to create a 100 meter radius on ...
5
votes
2answers
138 views
Creating grid following points in QGIS?
I am working with a set of coordinates from a csv file that creates a grid (of points) in QGIS. There is an id attribute along with the X and Y coordinates for each point.
I need to work with a ...
1
vote
1answer
45 views
Varying layout map scale based on layer visibility in QGIS?
I am looking for a method to vary the map scale of a QGIS layout according to the visibility of a layer.
The output should show the minimum scale at which the layer can be seen in the layout from a ...
0
votes
0answers
45 views
Decrease geopackage file size QGIS [on hold]
I have a few geopackage files that are each about 2 GB in size. Is there a way to make them smaller?
2
votes
1answer
48 views
QGIS Mutually exclusive legend within a shapefile
I have a shapefile with 30 different categories/symbols which I would like to make mutually exclusive. I am able to make the shapefile itself mutually exclusive by adding it to a group, but not the ...
-1
votes
1answer
38 views
Seeking QGIS equivalent for ArcGIS route editing tools?
In ArcGIS Desktop I frequently use the route editing Tools for line features and I was wondering if the same or similar tools exist in QGIS as well. I couldn't find them so far.
With "create route" ...
1
vote
1answer
27 views
Converting Longitude range from (0,360) to (-180,180) in Python or by using gdal commands
I have a raster downloaded.
Visualising it in QGIS.
I want to correctly project it so that its extent varies with longitudes from -180 to 180 instead of 0 to 360.
gdalinfo filename.nc outputs the ...
0
votes
0answers
18 views
Using Virtual Raster File Viewer of QGIS?
I have created a virtual file using Build Virtual File functionality of QGIS.
Is the file linked strictly to where the raster files are stored or can it be viewed on another computer?
2
votes
2answers
46 views
Copying feature from one layer while mapping fields in QGIS?
I am trying to copy features from one layer to another. What I would like to do is for QGIS to ask me which field should each field copy to.
For example, layer A has 4 features that I am trying to ...
1
vote
1answer
116 views
Seeking tutorials online explaining how to draw squares (having specific length) in QGIS?
I need to produce in QGIS a square having a specific dimension (1km x 1km). First I created a new polygon layer, but when I start editing through the Advanced editing tool, the program crashes. I ...
3
votes
1answer
38 views
Exporting attributes from QGIS to .dxf/dwg
I have a QGIS point layer with attributes in table. I want to export a layer with some of the attributes as a CAD block with attributes. Is it possible to do something like this?
0
votes
1answer
40 views
QGIS 3.4. project file editing
How can I edit a QGIS project file so that it would open, save and edit data from given folder and save the results for different directory? Kind of like MapInfo's Wor. file.
I read from QGIS ...
3
votes
1answer
61 views
QGIS make line attribute
How to automatically load all my attribute values into a layer after manually adding an attribute field? Or how to achieve the effect of PointConnector plugin in a more flexible that retains ...
3
votes
1answer
47 views
Eliminate Sliver Polygons QGIS 3
I'm a regular user of the 'Eliminate Sliver Polygons' tool in QGIS. I've just switched from 2.18 to 3.4.4 and the 'Eliminate Sliver Polygons' tool isn't available. Has it been removed from this ...
2
votes
1answer
62 views
Filtering by multiple attributes in QGIS
I have a layer that contains multiple attributes in multiple fields that I would like to select between without needing to type out a query each time.
I am able to do this with extract by expression,...
