Questions tagged [qgis]

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

Filter by
Sorted by
Tagged with
0
votes
0answers
12 views

QGIS forms : field display based on the value of another field

I have a form designed in QGIS 3.8.1. The form is associated with a layer for inputting data. Many of the fields on the form are only relevant if the first field is equal to True. Example: Field 1: ...
1
vote
1answer
26 views

Managing PostGIS default privileges for users in QGIS?

I have a PostGIS database for several projects, most of which we work with in QGIS. Each project has it's own schema. For each schema I have created a group role project-members, where project is ...
3
votes
1answer
127 views

Incorrect result while adding points along geometry in QGIS

I'm trying to add points along lines every 3 metres but I'd like the starting/ending point at certain non fixed distance. When I use the tool 'Points along geometry' inside Graphical Modeler. I don't ...
2
votes
1answer
27 views

Spatial distribution of vector polygons

I have two vector layers and I am looking for a tool for spatial distribution of the polygons. polygon 1 is the frame, polygon 2 are objects with different size and distribution. I need an index value ...
3
votes
1answer
47 views

Finding sum of points values within distance from paths

I'm willing to plot public transport data for a university project, and I'm currently trying to find out roughly how many people live with a reasonable distance from a set of bus routes. I have my ...
2
votes
1answer
58 views

Making colored hillshade in QGIS?

Today I found that ArcGis can make colored hillshade like on piture below. Here is link to their blog. I want to do that in QGIS. I know about layer coloring feature, and it's close for perfect, but ...
1
vote
1answer
15 views

Exporting NetCDF layer with defined colors using QGIS?

I have average wind speed NetCDF file (.nc) that I imported to QGIS. Then I defined colors for wind speeds in equal interval (3, 3.5, 4, 4.5 etc). Now I would like to save this colored map for sharing ...
1
vote
2answers
61 views

Aligning an edge to match another edge

I'm new to QGIS and I wonder whether there is a tool that helps to adjust the edges between two or more polygons; similar to that topology tool that's used in ArcGIS. http://desktop.arcgis.com/en/...
1
vote
1answer
119 views

Rounding numbers in QGIS raster legend?

Is it possible to have the numbers in the raster legend automatically rounded off? In the example below I'd like the labels to be 8, 29, 51 and so on. I know I can manually edit the labels, but is ...
0
votes
0answers
15 views

Selecting text characters within a string, or multiple field characteristic results as independent values? [duplicate]

I'm working to map data out using information extracted from a database where values were input based on characteristics assigned by a reviewer. I'm looking at mapping characteristics of a building's ...
1
vote
1answer
13 views

(QGIS) Shapefile with attribute table: Convert it to raster burning values of each polygon to the raster. “Heatmap”

I am working on QGis with a shapefile with an attribute table, I have created this shapefile through "Vector->Analysis tools->Count Points in Polygon", so this new shapefile got the count in the ...
1
vote
1answer
15 views

How to import CLR in QGIS python?

I created a plugin and I added my separate python file(added in plugin path itself) in the created qgis plugin. In that separate python file, I called a DLL file like below, import sys import clr ...
2
votes
1answer
95 views

Transposing raster values on the fly in QGIS

Say, I have a raster with some annual statistics data. Then Daily avg = Annual / 365 Weekly avg = Annual / 52 Monthly avg = Annual / 12 I know I can do this via Raster calculator in QGIS (v2.18.15)...
1
vote
2answers
146 views

Error adding qgis.org repository public key to apt keyring

The old QGIS key ring qgis-2017.gpg.key is expired and generates a warning during apt update today. Following the QGIS instructions, I tried to update the key as follows: wget -O - https://qgis.org/...
0
votes
3answers
410 views

pyQGis scale based visibility problem

Im loading some layers from postgis using pyqgis in my standalone qgis app. For each layer i also load a style using: lyr.loadNamedStyle("style.qml") I've setup 2 versions of styles in qgis desktop, ...
0
votes
1answer
128 views

Highlighting an area of a map

I would like to have a borderline around a subset South-South(SS) part of the map (Map 1) (More like highlighting the subset part). I tried to clip a vector of the subset (map 2) to the entire map, ...
1
vote
0answers
22 views

Correction of GPS-Track, snap to road (line, network)

Problem as shown in the image: I like to correct the GPS track (orange) to the right road (black). In a network of roads it is difficult to snap to the right path - for human it's obvious which one ...
0
votes
1answer
26 views

In QGIS: NetCDF image too pixelated

When i import NetCDF file (.nc) to QGIS then I get a picture that consists of quite big pixels. Is it somehow possible to soften those pixels to get something like this:
3
votes
1answer
35 views

Merging lines based on distance from point in QGIS

I have 5 groups of 4 lines, all the lines in all the data sets are centred around the same point. I need to algorithmically combine these lines into one line that is only the furthest from the point. ...
2
votes
0answers
40 views

Splitting layer with many polygons into independent shapefilles? [duplicate]

Is there any way to save many shapefile, which are not multipolygons, into shapefile, and then iterate over them? I have shapefile with plot polygons and I want to have each one independent in order ...
0
votes
1answer
137 views

Automatically Generate Attribute Table in Qgis

I am working with historical parcel data in Qgis and have the following fields in my attribute table, (name, grantee date, grantor date, parcel ID, acreage, previous owner). Unfortunately, I have ...
0
votes
0answers
22 views

QGIS map legend rendering problem

The maps look good, and the legend symbols match the maps. Once converted to .pdf the map legend symbols degrade to basically nothing. Horizontal red line patterns, or any colored line patterns for ...
2
votes
2answers
44 views

Joining CSV to shapefile with same Name field results in NULL fields

I am having some issues with using the join feature between my shapefile polygons and my CSV data (originally a xlsx file), when I join the layers together using the common field between them (name) ...
1
vote
1answer
196 views

Generating Tiles with QGIS

Is there any in the year 2019 working plugin? I try QTiles but this make errors (https://github.com/nextgis/QTiles/issues/100). So I need an alternative that is working with QGIS 3.6 How I can produce ...
1
vote
1answer
53 views

OS X PYTHONPATH for QGIS Standalone Apps?

What's the correct PYTHONPATH for OS X and QGIS 3.4? I want to make a QGIS standalone app but get the "ModuleNotFoundError: No module named 'qgis'" error. This happens after following the OS X ...
0
votes
0answers
58 views

Updating large Shapefile with new polygons

In QGIS I have a multipolygon layer that has about 100 polygons in it (property boundaries) and I will need to continually add polygons to it as they become available. What is the most efficient way ...
1
vote
1answer
24 views

Show/mark not visible labels (colliding labels)

If "show all labels, also colliding" is not active, some colliding labels will not show up. So far so good, but I would like to know, how often and where this happens and maybe why. Something like a ...
1
vote
1answer
36 views

QGIS: Joining data from multiple road lines onto polygons by location

I'm looking to add traffic data linked to a polyline shapefile of road centerlines to a multipolygon shapefile of land parcels. I want to join this data using proximity to roads instead of by matching ...
2
votes
0answers
23 views

How to custom format my coordinate grid?

I am custom formatting my coordinate grid. Is there a way to change the following formula so that the output comes with a decimal and suffix: substr(@grid_number, length(@grid_number) -6,5) The ...
2
votes
0answers
23 views

Transferring layer files from ArcGIS Pro to QGIS

I have access to ArcPro at my workplace and will be transferring a project over to someone who will be using Qgis. I have saved my layers as a layer file but the problem is that the other person is ...
3
votes
0answers
26 views

Displaying QGIS's “Map Tips” in OpenLayers?

Still a little new to QGIS and Openlayers. How would you display QGIS's "Map Tips" into OpenLayers? I am currently using QGIS 2.18 and have the latest update in Openlayers. In QGIS, I have created a ...
2
votes
1answer
30 views

How to get the type of the largest polygon inside a grid cell?

(1) I have a vector grid layer. (2) I have a multipolygon layer. Each polygon has a specific type (in this case a vegatation type) Now I want to get as an output the grid layer where each cell ...
0
votes
1answer
43 views

Rasterizing MULTIPLE vector layers in same “grid” so I can do a regression of sorts across pixel units?

For my research, I have collected a bunch of climatic data from my state in vector form. I also have my raster data, which is about 60 points around the state that have a binary assignment of yes/no. ...
0
votes
0answers
21 views

Point Geometry doesn't have X and Y values and prints (0,0) as it's coordinate but overlays properly on satellite imagery

I have downloaded a point layer which is in the projection WGS84 as per it's .prj file. It also displays properly on the map and when I hover over points it shows the correct lat long. But when I ...
0
votes
2answers
60 views

Geographic coordinates in PostGIS to QGIS and shapefile layers

I've got in PostgreSQL/PostGIS the table "points" with latitude and longitude fields. I've done update points set geom = st_point (longitude, latitude); and also select updategeometrysrid ('points'...
2
votes
1answer
166 views
+50

Clip all layers of a GeoPackage (GPKG) in one step

I would like to clip all layers of a GPKG-File to a given extend (canvas, mask layer, rectangle...) in one step. I could use clipping in batch mode but isn't there a nicer solution doing this in one ...
0
votes
1answer
55 views

QGIS Project saved in PostgreSQL not loading on other computers

I have created QGIS projects that are reading from PostgreSQL(data source). I then saved the individual projects to PostgreSQL in the public schema under their respective databases. When I open or ...
19
votes
2answers
31k views

Controlling Image Output Settings in QGIS?

I am exporting a QGIS map to an image format. I would like to have control over the output settings of the image (dpi), as currently it is only exporting the images at 96 dpi. Does anyone know if ...
1
vote
2answers
187 views

How to pan/zoom while QInputDialog

I'm iterating over a layer with a python-script in QGIS 2.18. I am going to pan to every feature and ask the user a question regarding this feature an do something depending on his answer. How is it ...
0
votes
1answer
17 views

Give non-overlapping parts of 2 rasters a value 0 (QGIS)

Is there a way in QGIS to give non-overlapping parts of 2 rasters a value of 0 in the new raster file? I would like the data gaps in the velocity file (so where Ice mask is displayed on the chart) ...
0
votes
0answers
18 views

Connecting QGIS 3.4 to a MS Access database

I try to connect to MS Access and i have already created an ODBC connection. Now, I have the the problem that I cannot open the database in QGIS (but the connection was succesful).
4
votes
2answers
1k views

Customise the splash image of QGIS

Where can I find the splash image which is shown while starting QGIS, and how to customise it? I am developing a GIS software for myself based on QGIS, but I don't want to just start anew with QGIS's ...
1
vote
1answer
37 views

Adding points randomly inside a polygon from an attribute table to a different polygon layer

I have two layers: 1. One with polygons geometry 2. CSV table with more than 600k rows They have an atribute ID in common, so, I want to distribute randomly each row, inside the polygon as a point. ...
3
votes
1answer
32 views

Problems with analyzing MODIS Aerosol Optical Depth

I want to extract AOD from the following hd5 file.Would be grateful for any help. Objective is to have a tif file projected in EPSG:4326 with values of all 3 bands. https://e4ftl01.cr.usgs.gov/MOTA/...
1
vote
0answers
29 views

PYQGIS 3: Processing Toolbox, output vector & raster layers

I figured out that besides from the python editor within QGIS, the layers that I'm creating in my .qgs projects with a Processing Toolbox are not saved and displayed. --> see image: 1) what I get ...
2
votes
0answers
22 views

Batch process aligning multiple rasters in QGIS

I would like to know if there´s a way to run a batch process that consists in aligning (changing cell size from 10 to 20 in Sentinel 2 imagery) in QGIS 3.4? I need to resample band #8 (resolution 10m)...
2
votes
2answers
58 views

Change path to help in QGIS 3.4.8 LTR

I want to use the offical help from qgis, which I can open with the F1 button. But it doesn´t work. I always get this message: I checked the Settings → Options →System, the path is right. And in the ....
1
vote
0answers
22 views

Change the azimuth of Graticule lines

I have created polygon graticule and I used ''polygons to lines'' to change the polygons into lines. I want to change their azimuth to make them more feet into my polygons. I had the idea to calculate ...
3
votes
1answer
52 views

Calculating the number of days between two dates as number

For some expression in QGIS I need to get the number of days between two dates as numeric value. If I substract two dates I get an interval back: to_date('2019-12-31') - to_date('2019-01-01') gives ...
-2
votes
0answers
44 views

Switch from 3 to 3.8 for QGIS [on hold]

For QGIS 3 there is a plugin called open layout, I have installed 3.8 and what is the QGIS 3.8 plugin called, for open layout?