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Questions tagged [qgis]

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

2
votes
1answer
58 views

QGIS split vector layer gives me GPKG files but I need shp files

QGIS 3.6.0 I am new to QGIS software and not very technical on its deep workings. I am trying to split a .shp file using split vector layer. I need .shp file outputs but it auto creates .gpkg files. ...
0
votes
0answers
46 views

Install QGIS 3.4.5 LTR on CentOS 7

I have already read this post but, I am still getting problems with my QGIS installation, and always show error with libgeos-3.4.2.so. I think, is because the default GEOS version installed by yum ...
1
vote
0answers
32 views

Channel network polyline shapefile filter [closed]

I need to filter the red polyline shapefile keeping only the real channel network without the little features (noise). I use ArcGIS
2
votes
1answer
41 views

QGIS print file title

How to automatically make the title of your print equal to the name of the printed layer? Tried by using the next piece of code, but it doesn't work (QGIS 3.X): from qgis.core import * from qgis.gui ...
0
votes
1answer
45 views

Merge small underlying polygons into overlaying shapefile with larger polygons [closed]

I have a dataset with the average rent prices saved in a vector layer (.shp). It is "street" based, so it has quite a fine resolution. I have a different dataset (containing info about crime rates) in ...
1
vote
2answers
40 views

Altas with rules on different layer than the cover layer [duplicate]

I need to generate an atlas based on a polygon shapefile, but I'd like to see just what is inside the polygon itself. Maybe with rules that involves other shape's attributes. Any suggestion?
0
votes
0answers
22 views

How to make the background of an shapefile the vector layer? [duplicate]

So from another question I asked about show raster layer over background, I learned how to duplicate a shapefile and use the inverted polygons tool to make the land the vector layer. I am now ...
6
votes
3answers
750 views

What happened to QGIS 2.x LTR?

I've been using QGIS 2.x LTR version for quite some time now (mostly for Lizmap webclient because 3.x didn't perform as well), but today as I wanted to install QGIS on another PC, I realized I couldn'...
0
votes
0answers
45 views

QField 1.0.0: How to clip and use a Google Satellite Hybrid basemap offline?

After a few attempts I've transferred my QGIS project successfully to Qfield. I'm using Google Satellite Hybrid as my basemap and need to use it at as high a resolution as possible offline. I've ...
1
vote
1answer
28 views

CRS of QGIS CAD tool and measure line tool

Does any one know what CRS the QGIS digitizing toolbox (CAD tool) and the measure line tool use? Because I couldn't find any way to manually set the CRS for the tools in QGIS 3, my assumption is ...
4
votes
0answers
41 views

Creating a segment for fixing water pipes and finding disconnected areas

I'm wondering if there is a tool for this problem. I'm using QGIS 2.14.2. Basically I want to select a pipe and find closest valves there is and to turn them off. After that I need to find all pipes ...
2
votes
0answers
20 views

Traceback Distance Matrix

I am using the QGIS Distance Matrix to calculate the distance of points along a line to that specific line. I used the tool before with 2 points layers and it worked well. This time I created a ...
2
votes
0answers
42 views

Difference between units in QGIS: Map Unit vs. Millimeter vs. Inch vs. Pixel vs. Point

In QGIS 2 there were three Unit types: Map Unit, Millimeter and Pixel. With a new version of QGIS 3 two additional arose Inch and Point. What is the difference between those Units, in sense of their ...
0
votes
0answers
14 views

Filtered WMS from QGIS 3.2 Python console

I am using QGIS 3.2 and I am trying to get the WMS with a filtered display based on an attribute. The code works but the WMS is not filtered. urlWithParams3 = 'url=http://localhost:8080/sso/wms&...
1
vote
1answer
42 views

How to auto populate feature attribute values for new polygon (B) from parent layer (A) where B is made over layer A?

Is there any way in QGIS where we can auto populate new layer feature_attributes from parent layer? We have layer A as . It has attributes including: f_id, class_name, class_type, r_total. We now ...
2
votes
1answer
61 views

Which Units Geometry Generator in QGIS works with?

While modifying some geometries in QGIS in my previous question Adjusting flow map styles in QGIS: Varying buffers' sizes I ended up with a huge confusion regarding the dimensions/units that Geometry ...
2
votes
1answer
32 views

Computing Shortest Path Distance for multiple points in QGIS

I have been looking for ways on how to compute the shortest distance between one point to multiple points using a specific road network. I have not been successful in achieving the solutions in this ...
0
votes
0answers
17 views

ECW errors on ubuntugis

i have successfully installed the ECW support on ubuntu qgis. the main challenge that i have is that whenever i try and load an ecw file, the qgis main window crashes. On the other had i am able to ...
1
vote
0answers
47 views

QGIS 3.6 Ordinary Kriging Error

I have downloaded a couple of landsat 8 images and created NDVI raster layers. I clipped these layers to the size of a polygon I created and found the average of them. I used the raster pixel to ...
1
vote
1answer
50 views

Convert to geospatial PDF issue

I just installed QGIS 3.6 on a new Macbook pro running Mojave, and I'm trying to produce geospatial PDFs of some basic maps of property boundaries overlaid onto aerial imagery base maps to use in ...
0
votes
1answer
33 views

Find higher elevation (10m) perpendicular point from stream network at regular interval

I have a stream network and for that network, I want to find the points at regular intervals which lie at 10m distance perpendicular from the stream.The final goal is to find the buffer of that 10m ...
0
votes
1answer
82 views

QGIS 3.4.4 and 3.6 SAGA Tools all not working with same error

C:\OSGeo4W\bin>exit Execution completed in 12.17 seconds Results: {'SHADE': 'C:/QGIS/output/HS.sdat'} Loading resulting layers The following layers were not correctly generated.C:/QGIS/output/HS....
-1
votes
0answers
21 views

How to get lat/lon of points from GDB tables using QGIS?

I have a GDB dataset . To get the point lat/longs, I have imported this as a layer in QGIS. I can see the points in the layer. I then used the "Add Geometry Attributes" algorithm from "processing" ...
1
vote
1answer
34 views

operator FIELD_NAME IS NULL is not working

I have a map of soil properties. I am trying to exclude areas that are designated for protection from a selection on this map. I have tried to use the following query: SOIL_TEXTURE = 'clay' AND ...
1
vote
0answers
25 views

Dimensioning line with QAD plugin

I would like to use QAD plugin to emulate AutoCAD, especially to draw some dimensioning. There are two possibilities to do so: click on 2 points or select an object. I want to use the object ...
2
votes
1answer
57 views

QGIS 3 - shortest path routing for multiple pairs of origins and destinations over a road network [closed]

I'm trying to map routes from an O-D survey with about 450,000 individual trips with different start and end points defined by lat, long. I want to estimate total VMT for the area by extrapolating ...
0
votes
0answers
19 views

Sharing interactive/dynamic maps online with restricted access for free?

I've produced a number of maps for work using QGIS that I want to be able to share online, but I only want people within my organisation to be able to access the maps. QGIS Cloud looked perfect, but ...
2
votes
1answer
64 views

Adding vertices to multiple overlapping line segments in QGIS?

I have a polyline dataset of transit routes for my city. Around the transit stations, up to hundreds of routes overlap completely, but do not follow the correct path that the busses actually travel (...
1
vote
1answer
36 views

Clipping in PyQGIS2 working but error in PyQGIS3 (argument 1 has unexpected type 'str')

I am trying to clip streets by a layer with municipalities in them. I was trying to run this script in QGIS3 but obtain the error hereunder. Traceback (most recent call last): File "C:\OSGEO4~1\...
1
vote
0answers
35 views

Convex boundary of polygon [closed]

Is there any tool that can help me with my problem? I have polygons looking like this : And what I want, is to simplify or gain convex boundary of such polygons. I tried Simplify Polygon in ArcMap, ...
2
votes
2answers
30 views

Automatically (re)classify data from layer using QGIS?

Is it possible to automatically (re)classify the data of a layer? (properties-symbology-delete all-classify) Because now I have to do this manually each time my data source changes.
1
vote
1answer
58 views

QGIS filtering a whole field using NOT

I'd like to negate some values from my map using the NOT operator. However, i need to deselect a whole field which contains over 600 entries so I don't want to select each. Is there a way to do this?...
1
vote
1answer
25 views

creating lines (distances) from points within buffer - thousands of points and buffers

i'm trying to assess the connectivity of an arboreal species' pathway. i have (1) a vector layer with approximately 15,000 tree points and (2) a layer with a buffer created for each of these trees. ...
1
vote
1answer
37 views

Create categorized rendered from styles in QGIS 3.4.3

How does this tool work? I've been trying to use it but it needs xml file and I dont know how to create one and running the tool without inputting a style database returns a single colorised map Is ...
1
vote
3answers
128 views

Displaying single band from multi-band raster using QGIS

How can I extract a single band from multi-band raster in QGIS? I have an remote sensed image which has 6 bands (including NDVI band), I want to display each band separately, but have no idea how to ...
0
votes
1answer
34 views

How to get an ECW file into a database which QGIS can read?

I have ECW imagery I want to store in my spatial database. I am using QGIS and a PostGIS database. How do I do it? Everything I have read so far (its actually unreadable to me) seems way too ...
2
votes
1answer
44 views

When is it worthwhile to reproject in QGIS? [closed]

My QGIS project has various raster and (complex) vector layers from different sources, in different CRSes. Using reprojection on the fly, I don't have to reproject them. But should I, especially for ...
1
vote
0answers
34 views

No Data Analysis In QGIS

I have two rasters and am using QGIS 3.6 I want to know which areas in raster 1 that are "no data" are not "no data" in raster 2. I also want to know what areas in raster 2 that are "no data" are ...
0
votes
0answers
21 views

Problem with dialog boxes being too large for a small laptop screen

I'm relatively new to the GIS world having just started a course in QGIS. I've been relatively successfully using QGIS for a couple of weeks on my desktop (large display), but have just switched to ...
1
vote
0answers
46 views

QGIS plugin + project: Enter db credentials(password and username) programmatically

I am developing QGIS Python plugin. I have a QGIS project and layers stored in a PostGIS database. I don't want to store the password into the project and I want to avoid that user need to type ...
1
vote
2answers
32 views

How to make QGIS indicate that a layer has not CRS set in layer properties info

I have QGIS 3.4.5 32bits. I added to the canvas a shapefile which has no defined coordinate system, but QGIS correctly guesses is WGS84 and warns about it. However when I go to the properties of the ...
2
votes
1answer
57 views

File tools in QGIS 3 [closed]

What is the use of the download files tool under files tools in QGIS 3.4.3? I'm trying to bring a csv file directly from the web into my processing modeler but even when the tool runs successfully ...
1
vote
0answers
28 views

Make a script run indefinitly

I have created a script which reads a JSON file and based on the attributes creates a grid and assigns values to the grid. This JSON file may change. I wanted to create an infinite loop to run the ...
2
votes
1answer
51 views

QGIS 3.4.4 snapping does not lead to expected topology and st_relate result

I try to snap a line to a polygon boundary. This is working fine, due using the snapping option in QGIS (snap mode vertex and segments & tolerance 0 pixels) Line 1 is snapping to the polygon ...
1
vote
0answers
15 views

Why does the QGIS Conversion (Translate Format) fail in batch mode? QGIS 3.4.4

QGIS Conversion (Translate Format) will convert individual file from tif and tfw to tiff that does not need the tfw. But the batch process gives the error "Wrong or missing output value: Converted (...
-2
votes
0answers
47 views

Adding messagebox to a command button interface in QGIS? [closed]

I teach my students QGIS. As much as I try, when they need to use a new CRS, some of the students go to properties>Source>set CRS. What I wanted to do is add a msgbox every time they push this button ...
5
votes
1answer
111 views

QGIS: use geometry from different layer in symbology expression

I have a project with multiple layers. The purple dots are from a pointfile with the symbology-expression: z($geometry)> '14.5'. (so it only displays a purple dot when the Z-value is more than 14....
1
vote
1answer
41 views

Reprojecting a shapefile into 'geographic coordinates' to load into iTree Canopy with QGIS

I have a polygon shapefile in CRS EPSG:27700 British National Grid that is a boundary of a study area that I would like to load into the iTree Canopy online tool. https://canopy.itreetools.org/index....
1
vote
0answers
41 views

Can't load Python in QGIS

I am following a tutorial developing a Python plugin in QGIS. After completing the script for the plugin I got the following message the next time I started QGIS. Warning I am a complete novice with ...
1
vote
1answer
38 views

'QgsLayerTreeLayer' is not defined when running from python plugin but not when run in the console in QGIS 3

When I run the following in a plugin I get name 'QgsLayerTreeLayer' is not defined print('Loading raster layer...') #QgsProject.instance().removeMapLayer(tLayer) print("%s called %s" % (filePath, ...