Questions tagged [qgis]

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

Filter by
Sorted by
Tagged with
5
votes
1answer
56 views

Optimizing number of printing pages in QGIS

When I try to print under QGIS, due to the framing, it prints me 4 pages. Looking more closely, and one by changing the angle of the 2 pages, I am at 2. How do I automate this? Current situation: ...
0
votes
0answers
23 views

QGIS link to web server

I am working on a project for a volunteer organization and they want to know if it's possible to link a project to a web server? Along with that, they want it to be password protected. Does anyone ...
1
vote
2answers
92 views

Selection of names according to their termination

I would like to select cities in my attribute table according to their suffix. For example: select only cities which end with "ton". How can I do this?
3
votes
2answers
55 views

Making curved line between points by using QGIS Geometry Generator

I am testing different tree crown drawing options in QGIS. At the moment, I have found this option to be the most suitable for me. Code: convex_hull( combine(buffer(make_point($x-("...
2
votes
1answer
35 views

Exporting separately ground and the sea from QGIS as TIFF files

I am very bad at QGIS, but I really need to have TIFF of the area on the picture, to export it later to Unreal Engine. The problem is the sea. Unreal takes it as a part of the ground. It doesn't ...
2
votes
0answers
27 views

Combining DEM, GeoTiff and CityGML in QGIS

I'm trying to combine DEM, GeoTiff, and CityGML in QGIS to create a 3D representation like in this example. The problem I have is that:- The CityGML buildings are hovering above the 3D view and The ...
0
votes
0answers
23 views

Print layout of multiple maps revert to one identical map after save as image/zoom

I have a map with 8 graduated classes. I have created a print layout with 8 separate maps - one for each of the classes. I used "lock layers" to ensure that each separate map displays just ...
0
votes
0answers
24 views

QGIS Georeferencer Plugin missing compression parameters

I am trying to georeference a rather large PDF. I was successful in doing so without compression. However, when trying to make the map lighter, I added some compression. The options are: LWZ, PACKBITS,...
0
votes
0answers
41 views

QGIS Vector Geometry Vanished

I've been working on a project, in QGIS 3.16 Hannover (we started the project a while ago, in the Bonn version, but upgraded during the duration of project). Upon project completion we've been asked ...
0
votes
1answer
39 views

Changing symbology from simple marker into a vector (print of a building)

I've got a question about changing the symbology of a certain rule-based layer. See below as to the current simple marker: As you can see the house is given this grey color because of the added 'topo'...
3
votes
1answer
55 views

Changing field type of a shapefile

I have two polygon shapefiles that I need to merge. I applied 'Merge vector layers' tool from Data management in QGIS 3.16, but it took too long to process and I realized a message indicating that one ...
2
votes
0answers
36 views

QGIS Shortest path (point to layer) start point expression in modeller

When in QGIS I run processing tool Shortest path (point to layer) ... I am satisfied with the result (below picture red line). But when I try to run the same tool in QGIS modeller, the result is ...
5
votes
2answers
65 views

Extraction of line segments in front of the street

I have a layer of lines that represents a layer of plots. I want to eliminate all the inner segments to have only the segments that go out into the street. Thus, I want to determine the sum of the ...
0
votes
1answer
32 views

Importing vector files regardless of having point, line and polygon information using a geopackage in QGIS

How do I import vector files regardless of having point, line and polygon information using a geopackage in QGIS? I am used to using a geodatabase in ESRI's ArcGIS, but since my mac is not compatible ...
3
votes
0answers
51 views

EPSG:3857 to 4326 - incorrect geometry

I need to get simplified boundaries of all countries with some buffer around them (20 km). I am using QGIS, I converted my country polygons vector layer from 4326 to 3857, set buffer, used simplify ...
0
votes
0answers
26 views

Crop a satellite image to 32 by 32 pixel

I have a satellite image of resolution size 10 m. I want to get a cropped image of 32x32 pixels of that image using a polygon. I randomly generate a polygon no matter the size but to reduce the ...
1
vote
1answer
54 views

SLD GeoServer COPY of styled labels from QGIS -with a created centroid - every label moved manually with X and Y on different places

In QGIS both in line, point and polygon type layers (for rivers, settlements, lakes..) I created labels for the objects - I created a field X and Y (Decimal Number), so that I define their location (...
0
votes
0answers
25 views

QGIS: Plug-in to determine optimal distance between coordinate and shape file [duplicate]

I have coordinates of power plants and I would like to determine their optimal distance (shortest distance) to electric grid lines (shape file). How could this be done in QGIS?
0
votes
0answers
36 views

R in QGIS not working after change of computers

I have installed, uninstalled a couple of times, but still get the same issue. Windows 7 and QGIS 3.6.1 and latest versions if R and R Studio. It used to work perfect until I changed computers. R ...
5
votes
3answers
175 views

Calculating buffer distance for different groups of parallel lines in QGIS

I have a number of parallel lines (see here for the background: How to extend lines to Bounding Box in QGIS?). My final aim is to create the Centerline for each group of lines as illustrated here: ...
0
votes
1answer
29 views

Joining and Updating PostGIS data using QGIS

I have a PostGIS database with which I am currently using QGIS to manage the layers. Say I have a layer in PostGIS that I want to do a join to to add new data in. Is it possible to do this join in-...
4
votes
2answers
128 views

Extending lines to their Bounding Box in QGIS

How to extend lines to Bounding Box in QGIS as in the following image: Figure 1: Lines Figure 2: Lines extended to Bounding Box Link to Shapefile of Bounding Box: https://drive.google.com/drive/...
1
vote
0answers
39 views

QGIS does not polygonize [closed]

I have a .tif which I want to have polygonized. I take the Raster/Conversion/Raster to Polygon. QGIS 3.12 starts the process but never ends (once I waited half an hour). I maybe don't see a mistake. ...
2
votes
1answer
44 views

Does the cross over the projection graphic indicate the origin of the projection? [QGIS]

I am using a projection that I have defined from a WKT format, and not included in QGIS' default roster of projections. See below in the image. The origin of my projection is 40N and 100W. Why is the ...
7
votes
1answer
175 views

Creating wedge buffers from many to one in QGIS

I have two point layers. One point layer has many random points which are start points. The second point layer has only one point which is the endpoint. I want to create wedge buffers from the start ...
1
vote
1answer
65 views

Joining shape and comma delimited files

I am using QGIS 2.18.23 on Windows 10. I keep trying to link a csv file (Pits6) to a shp file (Pits). It seems to work but when I click on one of the pits I get none of the information in the csv file....
1
vote
1answer
37 views

How do I turn around the ticks on digitized faults?

I have downloaded the USGS geology symbology and can assign a symbol, e.g. thrust fault, to a digitized line, but I have no control on the direction in which the ticks showing. How do I tell QGIS in ...
2
votes
1answer
72 views

Generating Hough transform (Hough line transformation) of binary image using QGIS

How do I generate a Hough transform (Hough line transformation) of a binary image in QGIS? I tried in GRASS and I got Error: unable to fetch interface description for command I found from the link: ...
8
votes
1answer
128 views

Selecting features by quartiles in QGIS

I have a polygon layer. I drew a boxplot calculated from field area in the layer. How can I select the features whose area value is within interquartile range (25%-75%)?
0
votes
1answer
150 views

Creating oriented centerlines in QGIS

How do I create oriented centerlines in QGIS as in the following image: Input data is a shapefile of irregular polygons as in the image below and available on the following link:https://drive.google....
-1
votes
1answer
36 views

QGIS: Interactive cursor to know latitude and longitude in boundary layer (shapefile)

Is there a way of knowing the coordinates in a specific point of a shapefile (boundary layer/map of the country) in QGIS? Similar to what is done on Google Earth. As the cursor moves, the coordinates ...
0
votes
1answer
18 views

No FeatureTypeList in WFS published by QGIS Server!

The WFS URL I'm using to get service from QGIS Server has no data about the layers and features type. It should be noted that the WMS URL is ok. Is there any problem with the URL I'm using? Should I ...
4
votes
1answer
48 views

QGIS HTML labels only for objects visible on map

I'm printing QR-code that is generated on the fly in QGIS Print Composer. The URL to get the QR-code ist stored in a PostgreSQL database in the attribute-field "url". <img src = "[% &...
3
votes
0answers
89 views

Getting active PostgreSQL connection username when stored through authentication configuration in QGIS 3.16

How do I get the username on the current layer PostGIS in QGIS 3.16.2-Hannover? We tried examples: Getting active PostgreSQL connection username when stored through authentication configuration in ...
0
votes
2answers
67 views

Executing QGIS tools in Python from Linux Shell [duplicate]

I would like to execute a Python script which uses QGIS Processing tools. On Ubuntu 20.x I installed qgis, qgis-common, python3-qgis and python3-qgis-common. My objective is to execute the tool Exploe ...
5
votes
1answer
62 views

Adding page to layout after populating the page using PyQGIS

TL;DR How can I add items to the page (QgsLayoutItemPage) without using layout? I want to add an item to the 2nd (or 3rd, ...) page in the project layout. Normally, I can add the item to the 2nd page ...
1
vote
0answers
46 views

How to get centerline of each polygon (rectangles) in QGIS [duplicate]

How to get centerline of each polygon (rectangles) as in Figure 1 in QGIS to obtain centerlines as in Figure 2 Figure 1 Figure 2
4
votes
1answer
78 views

Exporting QGIS Field Calculator user defined function [duplicate]

I have created many Python functions in QGIS Field Calculator Function Editor. How can I export the user defined functions to use in other computers or share to other people? My QGIS is 3.12.1 on ...
1
vote
1answer
36 views

Drawing with interior angle and distance

In QGIS Azimuth and distance plugin draws with azimuth angle and distance. I want to draw with interior angle between consecutive lines. For the starting point and base station(reference point to plot ...
-1
votes
1answer
74 views

Applying Otsu thresholding method to raster in QGIS

How can I apply Otsu’s threshold method to a Raster in QGIS for reduction of a gray level image to a binary image?
2
votes
0answers
32 views

Rendering raster with fine structure at low resolution in QGIS

I have a raster showing a map with a lot of fine-scale structure (water depths and rivers) in QGIS, and I'd like to make the structure visible when the plot is low resolution. Up close, I have ...
2
votes
0answers
21 views

Retaining Bounding Box after Fishnet Clip

I have a large image that contains around 7000 trees. I created a bounding box around each one of them and then saved it as a .xml file. I would now like to create different fishnet sizes and clip ...
0
votes
1answer
17 views

Failing to load OS .gz files into QGIS 3.16 using OS Translator II

I'm new to QGIS and not strong on writing scripts or code. That said I've installed QGIS 3.16, PostGIS 3.1.0, PostgreSQL 13 and also OS Translator 2 and followed the configuration guidance at https://...
-1
votes
1answer
34 views

Performing an operation on all values in certain fields as specified in a list, then overwrite those fields in their layer file using PyQGIS

I'm stumped here. I want to multiply all of the values by 100 in all of the CSV files I'm using in this project for all fields other than the join field. I don't need to create a new field. I simply ...
0
votes
0answers
26 views

gdal2xyz Ignore nodata values

I am trying to export a DEM raster into a xyz file (for later use). I first clipped the raster in order to limit its extent and the lines in the xyz file. However, gdal2xyz does not ignore the nodata ...
6
votes
1answer
70 views

Difference between QGIS export and gdalwarp

Does QGIS export/save as use a different projection system/process than gdalwarp? I am working with MASIE ice coverage data available here. My goal is to automate the process of reprojecting the daily ...
1
vote
1answer
28 views

QGIS Create Feature for closed Polygons

I have one single layer that consists of different polygons. In the attribute table all the polygons are summarized in one feature (see picture for both). I am looking for a way to split up the ...
4
votes
2answers
134 views

Computing Excess Green Vegetation Index (ExG) in QGIS [duplicate]

I have to process the image for Sugarcane row detection and extraction. Sample image is accessible from the link: https://github.com/AndresHerrera/croprows_generator_pa_v2/tree/master/droneimages I ...
5
votes
0answers
41 views

QGIS vector field marker not respecting map rotation

I’m working on a map the shows point displacement between two dates. These are survey benchmarks that are surveyed periodically to observe slope movement. Symbolizing this is QGIS is straight forward ...
-1
votes
0answers
69 views

Image Enhancement in QGIS

Can I have assistance on methods to carry out Image enhancement: contrast enhancement, intensity manipulation and sharpening, and filtering on QGIS to produce results as in the following image: The ...