Questions tagged [qgis]

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

Filter by
Sorted by
Tagged with
1
vote
1answer
41 views

Overlapping topology layer issue on mapping crops QGIS

Trying to map cotton fields of CA using data from this site https://nassgeodata.gmu.edu/CropScape/ Can not get my map to have a topographic underlayer without the other crops showing up as well ...
1
vote
0answers
33 views

Google satellite xyz tile layer in QGIS has lower resolution than the basemap in Google Earth?

As far as I can tell, the Google satellite imagery loaded as an xyz tile in QGIS is the same image that is used in Google Earth, but at a lower resolution. The lower image below is from QGIS using the ...
2
votes
0answers
62 views

Elevation Profiles Using QGIS vs. Google Earth

I have several routes I am calculating elevation stats for. What I want is Total Ascent/Cumulative Gain, where all ascents and descents are accounted for. As opposed to solely the difference between ...
0
votes
1answer
31 views

Converting raster into polygon using QGIS?

I am using QGIS. I am working with a raster which basically shows like 5 colors. I chose some values with the raster calc in QGIS so I have now 5 different TIFFs where each "color" is defined as 1. ...
0
votes
1answer
30 views

Prevent GeoPackage from saving when it is not edited in QGIS

So in QGIS, GeoPackage will be automatically saved when it is read even if you didn't edit. How to avoid this from happening?
3
votes
2answers
30 views

Omitting certain style string labels in QGIS 3 rule-based labeling

I’m labeling airport taxiways. The taxiway labels are all strings but they tend to be one of three varieties and I would only like to show one of those. I’ve been trying to mess around with Rule-Based ...
1
vote
1answer
33 views

Seeking Transit Feed (GTFS) Toolset for QGIS?

I can see that ArcGIS has a transit feed toolset that enables converting the .txt files from GTFS data directly into usable feature classes for GIS. I am trying to develop catchment areas in the ...
1
vote
2answers
30 views

Maximum pixel value by color [closed]

I have an image with three bands that are RGB and correspond to percent values from 0 - 100. I want to create an image where the maximum pixel value amongst all three bands is one single color. For ...
1
vote
0answers
11 views

Image error polynominal transfomation

I'm georeferencing a Landsat 8 oli no QGIS trip. I include the control points and the system calculates the residuals for each point. At the end it indicates the polynominal mean error of the ...
1
vote
0answers
31 views

No longer able to change shapefile field types in QGIS 3.6 or 3.8 using Refactor tool

I'm looking to merge 3 shapefiles and I am changing field names and types to coordinate before the merge process. I have been able to successfully use the refactor tool to change field types before (...
1
vote
1answer
42 views

QGIS server installation: Do I need to create a qgis user?

I am following the instructions in the official docs to install QGIS Server (3.8) on my Ubuntu server (18.04). Throughout the docs, a /home/qgis/ folder is mentioned. 12.1.3. Follow Along: HTTP ...
1
vote
1answer
43 views

Missing points using QGIS2Web? [closed]

I have created a map with multiple points and path layers in QGIS 3.8 (Zanzibar). When I try to publish the map with the QGIS2Web plugin, there are two kind of results: When I use the "OpenLayers" ...
2
votes
0answers
22 views

Adding additional points to GCP table after an image has been georeferenced

I have finished georeferencing an image with no attached coordinate system. I was unsatisfied as the image was not accurately overlayed on the map. The dx/dy & Residual error values are not ...
2
votes
1answer
34 views

PyQGIS/PlugIn: How do I pre-check if processing function is executable before I get a QGIS critical error?

I built a PlugIn with the 'native:shortestpathpointtopoint' tool to find the shortest path between two points on a multipolyline. When I run the Plugin I want to get a message with information about ...
1
vote
1answer
48 views

Creating LAT / LONG grid labels with Northing/Southing and Easting/Westing suffix in QGIS?

I´m using QGIS 3.6. I have my map as you can see below: I would like to have the labels in LAT / LONG coordinates like (40E ; -10S). Can you please tell me how can I do this? I saw: https://...
0
votes
1answer
39 views

Visually show input data from attribute table on map

I have 8500+ point-locations in QGIS, all with unique ID numbers, showing on my map; however, the unique ID numbers are not displayed. Is there any way to filter this so that the ID numbers are ...
2
votes
2answers
48 views

Calculate Convex Hull based on attributes

I have a layer with lots of (spatially grouped) lines - lines belonging to a group share the same value in a field. I would like create convex hulls around each of these groups using QGIS 3.8. I ...
1
vote
1answer
66 views

Incomprehensible speed lowered situation [closed]

I recently started to learn QGIS system and used quite well to develop a project. I wanted to have faster outputs so I bought a new desktop. The old one specification is like this: CPU intel i5-7400 ...
1
vote
1answer
44 views

Where is config file for QGIS 2.18?

I search the config (.ini) file for QGIS 2.18 on my pc. For QGIS 3.4.8 the file is stored under this path C:\Users\AppData\Roaming\QGIS\QGIS3\profiles\default\QGIS\QGIS3 I can´t find this file for ...
1
vote
1answer
30 views

Calculating minimum distance between all points of 2 different point layers using QGIS? [closed]

I use QGIS 2.8.3 or 3.4 whatever works better. I need to calculate the mimumum distance between all points of 2 different point layers. I was reading this post https://gis.stackexchange.com/a/62212/...
1
vote
1answer
31 views

How to count points of a point layer (shp) for each depth class of a bathymetry vector layer

I am using QGIS 2.8.3 but also have 3.4 whatever works better for this issue. I have a bathymetry shapefile and a point layer. One of the columns of the bathymetry vector gives the maximum depth and ...
2
votes
1answer
44 views

Getting libpng error for QGIS on Ubuntu 19.04?

So I have already attempted the solutions that were posted here, and I still get the same issue even after reinstalling QGIS: libpng problems for QGIS I keep getting the following error message: ...
0
votes
0answers
13 views

ModuleNotFoundError: No module named "PKG.resources'

Trying to use plugin builder to work create plugins in QGIS 3.6 The conventional fix would appear to be running pb_tools the issue being that I can't get it to read everything from the right places. ...
3
votes
0answers
42 views

Get Isochrones for Public Transport in QGIS

I'm using QGIS and trying to get public transportation isochrones in Montreal for 20, 40, and 60 minutes. I was able to use the ORS plugin to do the same for cars, walking and cycling in the area. I ...
1
vote
2answers
77 views

Install Whitebox to QGIS

I am working in QGIS 4.8, and I am trying to use the Whitebox Processing plugin. I have Whitebox Tools and Whitebox GAT zip files installed and unzipped on my drive. However, I cannot use the Whitebox ...
3
votes
1answer
43 views

Incorrect raster extent in R but not QGIS?

I am attempting to read extents in R from a number of raster digital elevation models downloaded from here: http://www.tngis.org/elevation.htm In doing so, I'm getting incorrect extents for a third (...
1
vote
0answers
41 views

Measuring wrong, EPSG:27700 in QGIS3.6

If "enable on the fly" is on and the CRS changes at all during the lifetime of a project then seemingly, it refuses to measure (using the measure tool I just get 0.00000). So new project with all the ...
1
vote
0answers
15 views

How to show Turn Restriction data from OS MasterMap Highways on the map?

I want to obtain the location and details of all turn restrictions from the OS MasterMap Highway Network datasets I have. I tried loading the Turn Restriction dataset into QGIS but it does not read ...
2
votes
1answer
50 views

Extracting points as CSV from count polygon

By using "points count polygon" I found the number of points in every polygon. I have to extract those points to a CSV file but I can't. I came to know that I have 957 points in my 1st polygon (as ...
2
votes
1answer
51 views

Polygon area from Google Earth so different to QGIS & Shapely/PyProj?

I have a set of points defined by their longitudes and latitudes in WGS84 that define a polygon that I need to calculate the area of. I originally tried to approach this using pyproj and Shapely as ...
0
votes
0answers
27 views

QGIS 3.8 heatmap error

I had assumed it was an error due to lack of space but no matter where we try to save it we get the folllowing error: Traceback (most recent call last): File "C:/PROGRA~1/QGIS3~1.8/apps/qgis/./python/...
4
votes
0answers
38 views

QGIS export to PDF - rasterize only basemap layers but keep others as vectors

I am building my own map in QGIS 3.4 in which I created a basemap from ESRI satellite imagery and a ESRI hillshade overlay. On top I have several custom vector layers (country borders, city names etc.)...
0
votes
1answer
56 views

Red lines appearing in QGIS Georeferencing?

I am georeferencing some old aerial pictures in QGIS. The area encompass mountains, hills and a flat area. For some pictures the error is quite low and I am satisfied with the overlapping (error is ...
3
votes
2answers
52 views

Extracting or categorizing shared boundaries of polygons QGIS

I would like to recreate the style in this Wikipedia Locator map, where there are three distinct styles for boundaries: Coastline (thin blue line) High-level administrative land-border (thick grey ...
2
votes
0answers
31 views

Removing ONLY black background in QGIS (without removing black dots within the image)

Related to question: Removing black background and black font from raster in QGIS I have also a black backround and when doing as it is suggested in the answer the black backround goes away but also ...
2
votes
0answers
23 views

Create catchments/subbasins for specific nodes

I have an XPSWMM model of a neighborhood storm drainage system. Nearly all of the drainage is above ground through a network of ditches and culverts. I still need to create catchments for the ...
1
vote
0answers
38 views

Wrong scalebar for a map of Scotland

I am working on a project that focuses on Scotland. When I use the print composer to add a scalebar the scale is wrong. It shows 50 km for a distance that is probably around 200 km. Following the ...
0
votes
0answers
26 views

Getting to the code of a QGIS 3 plugin [duplicate]

So I installed a QGIS plugin and want to look how this plugin works internally. I have installed it within QGIS using the 'manage and install plugins' functionality. In the installation folder I ...
3
votes
0answers
34 views

Nearest neighbour joins for two geodataframes using KDtree from scipy/sklearn

I have a number of large geodataframes and want to automate the implementation of a Nearest Neighbour function using a KDtree for more efficient processing. The process I want to achieve here is to ...
2
votes
1answer
41 views

Tableview with 2 columns

I'm using QlistView to show my names of departement in the studied area after using the 'extract by location' processus: # res=QgsVectorLayer() # capture département inside the studied area : ...
2
votes
1answer
61 views

QGIS raster calculator ^2 operation gives negativs results

I want to compare 2 same tiles at different dates. I use the raster calculator like this : (IR_band_frb - IR_band-aug)^2 But I get this result : The data range goes from -6049 to 4486 ... Why I ...
1
vote
0answers
40 views

Error adding ArcGIS MapServer Layer to QGIS 3.6? [closed]

I have QGIS 2.18 and QGIS 3.6 installed on my machine (running Windows 10) and I am able to add ArcGIS MapServer Layers to my project in QGIS 2.18 without problems, but in QGIS 3.6, using the same ...
0
votes
0answers
11 views

QGIS Network - OD matrix within local neighborhood based on line feature length

I have a given road network dataset as polylines and want to create a network out it. For that, I found v.net from the GRASS GIS toolbox. Now (1) I'd like to get the OD matrix from the intersections ...
1
vote
0answers
33 views

Shortest route between large amount of points

I have to check the street lights of various communities. There are approx. 540 lamps to check, I was wondering if QGIS (or any other opensource software like PostGIS or R) can help me finding the ...
0
votes
2answers
47 views

QGIS changing map options distance units

I want to change the map distance units option in QGIS from metres to centimetres. I am currently using projection British National Grid EPSG 27700. I would like the print composer to print a map ...
4
votes
3answers
65 views

Counting number of polygons inside zone using QGIS?

I've seen a lot of questions about counting the number of points within a polygon but my question is I have 1 vector layer with polygons showing past landslides that have occurred and another 206 ...
0
votes
0answers
17 views

Converting an ASCII File to raster image using QGIS

Following a previous issue discussed --> Cross section profile distance not providing accurate distances? It was highlighted that 1. My CRS layer projections were different to one another. this was ...
1
vote
0answers
20 views

Vector tool menu missing in QGIS3

I am using QGIS3 on a Mac and the Vector tool menu is missing entirely. The processing plugin is enabled and online it suggested deleting .qgis2, which I don't have. Can anyone help?
0
votes
0answers
20 views

Create a grid in QGIS [duplicate]

I have GIS points (x, y data) for every minute over a landscape. If I load them up as a CSV into QGIS they all show up as points, which you would expect. However, what I would like to do is use these ...
1
vote
0answers
15 views

Raster Calculator in the Graphical Modeler of QGIS 2.18

How to convert this expression from raster calculator ("noise_heatmap_clip@1" <= 50) * 5 + ("noise_heatmap_clip@1" > 50 AND "noise_heatmap_clip@1" <= 100) * 4 + ("noise_heatmap_clip@1" > ...