Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
1
vote
1answer
13 views
Showing Outline of Island on Topographical Contour Map using QGIS?
I am fairly new to GIS.
I have been reading through this site and have not quite been able to figure out what I am doing wrong.
I am trying to create a contoured topographical map that I can cut ...
2
votes
1answer
16 views
QGIS 2.18 label by expression concatenate field strings
For a building layer I have an attribute table with several fields for the building type where data was entered with a manually created form using checkboxes. Example:
Production: 1 = (yes), 0 = (no)
...
1
vote
0answers
16 views
How to determine the status of snapping in QGIS 3?
I can use toggleEnabled to turn snapping on and off, but is there anyway to know the status of the snapping tool (on or off)? as toggleEnabled doesn't return a value nor does it take a value.
1
vote
0answers
13 views
Read a .csv file from a URL with an API call in QGIS 3?
How do I read a .csv file from a URL with an API call, including key, in QGIS 3?
I've tried creating a .vrt file as outlined here
I've tried the solutions presented here
If I'm doing everything ...
2
votes
0answers
29 views
Migrate QGIS2 projects to QGIS3
I have like 40 QGIS2 projects. If I open them with QGIS3 labels and svg icons are not displayed. I don't know if there is any other feature that is not working when upgrading to QGIS3 but I suppose ...
1
vote
0answers
14 views
Rasterize produces wrong result - R
I am trying to rasterize a polygon in R using teh rasterize function but the output is not correct. I am comparing the result with the output produced by the rasterize tool available in QGIS
May data ...
-1
votes
0answers
17 views
SAGA - QGIS open DLL
Is possible to load SAGA io_shapes.dll directly to tool in QGIS 3.6? I need export line shapes to xyz points.
0
votes
0answers
16 views
Strange values after vector to raster QGIS
I have tried to rasterize a vector file made by polygons, each one with own temperature value, but I got a raster with different values. In addition, the min and max values do not correspond to the ...
0
votes
1answer
16 views
How to change PostgreSQL layer encoding for QGIS Server
I'm actually stuck trying to update encoding of my PostgreSQL layers to be able to set my project as QGIS server project.
In the layers properties, I can't change the layer's encoding.
Any hints on ...
1
vote
1answer
17 views
What is the search mechanism in “join attributes by location”?
While running join attributes by location, we can either choose one to many or one to one mapping. In One-to-one, it assigns the first located features value.
What is meant by first located feature? ...
1
vote
0answers
22 views
How to solve this error?
I am getting this error message :
"Processing algorithm…
Algorithm 'Warp (reproject)' starting…
Input parameters:
{ 'DATA_TYPE' : 0, 'EXTRA' : '', 'INPUT' : 'C:/Users/DELL/Documents/Geodata/mosic.vrt'...
0
votes
0answers
20 views
From point with z value to “3D” line in QGIS [on hold]
Image to have a point layer with z values and you want to convert this point layer to a line layer. Each line layer node should contain the z value of the point layer.
Is this easily achievable in ...
0
votes
0answers
9 views
Printing shows extra lines on Print or ExportToBitmap
I am trying to print the following map (from LayoutControl)
But the actual output is different from expected one as below
There are extra lines and missing lines in resulting print.
I am creating ...
2
votes
1answer
71 views
How to dissolve shared line segments together in QGIS?
I have 2 features which are lines on a single layer re-projected to ESPG:2039.
I wish to combine them into one MultiLineString but in a way that their common part is merged to a single LineString. I'...
-1
votes
0answers
15 views
Python error : Couldn't load plugin 'processing' See message log (Python Error) for more details [on hold]
2019-04-23T19:14:57 WARNING Failed to load C:/PROGRA~1/QGIS 3.4/apps/qgis-ltr/plugins/grassplugin7.dll (Reason: Cannot load library C:\PROGRA~1\QGIS 3.4\apps\qgis-ltr\plugins\grassplugin7.dll: ...
-2
votes
0answers
31 views
Possibly wrong expression defined [on hold]
I have written code but it is not returning any value in the plugin.
def btn_nuf_pressed(self):
layer = geo_utils.LayerUtils.get_lay_from_id(self.cbo_layer.itemData(self.cbo_layer.currentIndex())...
1
vote
0answers
31 views
How to render OSM vector data to raster
I am using OSM vector data which has been converted into shapefiles. I have polygons representing buildings, landuse and lines representing roads as shown bellow:
I want to assign some symbology to ...
0
votes
1answer
20 views
How to perform viewshed analysis for each pixel in raster?
I am having a problem making a viewshed analysis for every pixel on a raster.
To perform the viewshed analysis from every single pixel in a raster I will need:
A viewshed plugin (which I am willing ...
1
vote
1answer
30 views
The Logic Marker Moving with the Offset Function in QGIS 3.6.2
In QGIS the location of the marker can be changed, without changing the coordinates in the Attribute Table. This is done by changing the X or Y values in the Offset function, located in the Layer ...
2
votes
0answers
30 views
How to create an index map of atlas features in QGIS 3?
I realise that this question has been asked before (Making overview with linked detailed maps in QGIS?), however I am still unable to figure out how to create an index map of atlas features in the ...
0
votes
0answers
30 views
Filtering attribute table in QGIS Atlas?
I have encountered a problem with filtering "show only features visible within a map" in QGIS Atlas ?composer.
I need to have an attribute table with all mileage posts visible within one map. ...
0
votes
0answers
9 views
QGIS OpenCL and eGPU on Mac [on hold]
I'm using a Mac Mini with a Radeon RX Vega 64 as external GPU but the OpenCL Acceleration doesn't seem to be supported. Does anyone know if QGIS lacks support for this chipset or is there anything I ...
0
votes
0answers
25 views
Data security under WebGIS by QGIS
We would like to offer our Client a webGIS solution for showing/Monitoring their data. Based on my Knowledge WebGIS by ESRI would be helpful and provide the user with the Login Information and it is ...
1
vote
0answers
32 views
How to use ATOM FEED Data in QGIS 3.6.1?
I would like to know how I can work with ATOM FEED Data in QGIS. In ealier QGIS versions this worked with the Plugin "INSPIRE ATOM Client", but this Plugin doesn't work in the current version.
An ...
1
vote
3answers
42 views
Showing two sets of points from two different fields in QGIS?
I made a union of two adjacent shp (points) files with the same theme (Geochemistry) so the resulting attribute table gave duplicated fields, for example: ID, As_ppm, Ag_ppm, Pb_ppm, ... , ID_2, ...
2
votes
1answer
46 views
Knowing/converting AREA, PERIMETER units in QGIS?
I use Convexhull tool in QGIS and there are result value :
AREA = 0.0017494390 PERIMETER = 0.1725495172
I thought the result was strange. So, I took a rough estimate of the points through the ...
0
votes
0answers
19 views
Fixing tiny microscopic Map font size on UHD?
QGIS 3.0
Added OSM layer via QuickMap services. This is what I see on my UHD display:
I understand that tile server just seeds tiles and we don't have any control over tiles generation. But why not ...
1
vote
2answers
46 views
Filter points by proximity
Is there any tool/plugin in QGIS that will allow me to filter a point layer to remove all points closer than a given distance? I have a project in which I need no points to be closer than 50m from ...
0
votes
0answers
16 views
QGIS @parent or import to database(Error 7) not working for layer
I have a shape file layer that won't load into the SpatiaLite database and it gives Error 7. It also won't run functions that work in other layers and works fine without the @parent or if I remove ...
1
vote
0answers
25 views
Aligning font when rotated using QGIS?
I added a label in the print composer of QGIS (3.6). I rotated the label, but then the font is no longer aligned to a common line. I think it is stair-stepping where the letters go, perhaps snapping ...
1
vote
1answer
48 views
Layer not visible after deleting from attribute table QGIS
I'm a newbie for QGIS and trying to learn.
I was editing the attribute table in which process I deleted some rows. Then the layer became invisible in the project. After trying a lot I decided to redo ...
1
vote
0answers
13 views
Replicating the Layers Panel in my app, with sub-layers [on hold]
I've followed this post, using the QGIS Desktop Python Console, to create color ranges for my vector layer. QGIS displays a nice selectable tree in the Layers Panel.
Now I want to develop my own app, ...
0
votes
0answers
29 views
Removing inner border of merged polygons using QGIS? [on hold]
How do I remove the border of two polygons created from bordering raster images?
I used dissolve but it filled other areas and in some cases removed the feature table completely.
I'm new to QGIS ...
0
votes
1answer
17 views
Blown out TIFF image after merge in QGIS?
I'm attempting to merge four GeoTIFF images in QGIS for the first time and am getting unexpected results.
Navigating to Raster --> Miscellaneous --> Merge..., I set up the merge as follows:
Once the ...
0
votes
0answers
24 views
Cannot convert 'nan' to double, QGIS Field Calculator [on hold]
I have about 1,6 million lines I need to get the bearings of (0-360).
When running below code in Field Calculator, I get error after a few seconds "An error occurred while evaluating the calculation ...
0
votes
0answers
15 views
Install SWAT hydrological model on Ubuntu [duplicate]
I am trying to go back using Ubuntu in my work as hydrologist.
Is there any way to install the SWAT model, and in particular QSWAT on Ubuntu?
3
votes
1answer
88 views
latest version of QGIS fails to edit attribute table of GeoJSON file
I am using QGIS 3.6.4 and working with GeoJSON files. I have come across a very annoying problem. Whenever I try to add an attribute and assign values to it using the field calculator, the values will ...
0
votes
0answers
23 views
My work closed and now I cannot see the Temporary Scratch Layers [duplicate]
This is my first project on QGIS 3.6.1. Over night my computer restarted and updated itself closing my QGIS work.. I created two separate Temporary Scratch Layers and frequently saved it on my ...
0
votes
0answers
20 views
OpenLayers Plugin Issue
I get this error when pulling a map from the OpenLayers Plugin. See Below.
An error has occurred while executing Python code:
AttributeError: 'OpenlayersLayer' object has no attribute
'...
-1
votes
0answers
18 views
indendation error after typing code in the QGIS python console [on hold]
I just started to study the python console in QGIS and follow a tutorial. Unfortunately, the code I copied doesn't work and I have no idea why. Can somewhat explain it to me.
layer = iface....
0
votes
1answer
50 views
NameError: global name 'layer' is not defined
I've modified code of a plugin go2nextfeature as below
import os
from collections import OrderedDict
from geo_utils import utils as geo_utils, vector_utils as vutils
from qgis.core import *
from ...
3
votes
1answer
84 views
Simplify multiple lines: create central axis?
I have a layer with railway lines, downloaded from OpenStreetMap. Every single track is represented separately, so at trainstations, you have several parallel lines, as well as sidelines that lead to ...
0
votes
0answers
23 views
Printing satellite imagery from ArcGIS Server using QGIS? [on hold]
I am using QGIS 3.6.1 I made a map (my first one ever) that includes satellite imagery that I obtained from the ArcGIS Server. The map looks perfect in the Layout, but when I save to a file (PDF, ...
0
votes
0answers
22 views
Using list of attributes to create layers?
I have a very long list of values (over 2000 rows) in the following format:
1: TAY100, AB60, EM10
2: CA40, 9, UT26, 24
3: YO56, YE
I have a layer with features each with a distinct attribute called ...
0
votes
0answers
17 views
RGB image file to Y'CbCr and other Luma+Chroma Representations
is it possible using QGIS on windows to convert an RGB image file to Y'CbCr and other Luma+Chroma Representations format.
I've seen various formulas for this written in MATLAB and R. I am looking to ...
1
vote
0answers
49 views
Grid rendering in QGIS?
Rendering a grid in QGIS causes problems: The outmost grid line is not drawn on different zoom-levels:
Here it is ok:
While here it is not ok:
I have tried to change these rendering-settings, but ...
5
votes
1answer
54 views
Customizing QGIS plugins
Is a user legally allowed to make changes to available plugins according to his needs? e.g. changing UI, code etc but not the licenses and other info.
0
votes
1answer
23 views
Table Join on distance measures returns NULL
I followed every step of this tutorial but when I join the distToRoads and distance in m I get a table distToRoads which contains just the null vaues, why is that?
Tutorial: https://www....
0
votes
1answer
37 views
Continuous buffer from individual polygons in QGIS
I have a stream segment for which I am trying to find a buffer around with criteria as 5m of elevation. So for each straight line within a stream segment, I have found buffer (polygon) for it. Now I ...
1
vote
1answer
44 views
Export road system to CSV file
I'm using QGIS to extract coordinates of a road network.
Concretely, I downloaded a mbtiles file from Internet and loaded the file into QGIS like following:
Then I tried to export the layer ...
