Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
-2
votes
0answers
19 views
Possibly wrong expression defined
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
23 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
0answers
13 views
How to preform viewshed 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 ...
0
votes
1answer
19 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
22 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
25 views
QGIS Atlas attribute table filtering
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. Although ...
0
votes
0answers
7 views
QGIS OpenCL and eGPU on Mac
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
24 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
23 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.
1
vote
2answers
36 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
41 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
18 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
44 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
15 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
24 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
46 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
23 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
87 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
47 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
83 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
16 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 ...
4
votes
1answer
44 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 ...
1
vote
2answers
32 views
Getting just land and water layers in QGIS with QuickOSM?
How can I just get land and water layers that I can style with different fills and outlines?
Really - Just "land is green, water is blue" layers (that I can then add other layers on top of)
I'm ...
0
votes
1answer
26 views
Expression returning wrong value in QGIS Field Calculator?
My QGIS Field Calculator expression:
case when "field_value" = '' or "field_value" <> NULL then (if( "field_value" = '', 'N', 'Y')) end
returns null value even if "field_value" has something ...
0
votes
2answers
50 views
Updating two or more fields in QGIS?
I have 5 layers:
NAM_USA (It has four fields of our interest, named 'bare', 'sand', 'woody' and 'built' depicting feature counts in each of the below corresponding layers.)
Baresoil
Woodyland
...
2
votes
1answer
75 views
Exposing GRASS GIS add-on in QGIS Processing framework?
Having QGIS and GRASS GIS 7 installed, how can I expose a GRASS GIS add-on, which has been installed using g.extension, in QGIS' Processing framework?
0
votes
1answer
32 views
Join by location (summary) returns null
I am trying to count points within polygons (311 calls by Census tract). Both shapefiles are EPSG 4326, and I've done define projection just to double-check. Every time I run Join attributes by ...
1
vote
0answers
14 views
Spatial join for closest features and using a sum merge rule in QGIS
I am trying to perform a spatial join based on nearest neighbor ("CLOSEST") spatial relationship in QGIS, and by summing the results of the join where multiple matches occur.
In ArcMap there is a way ...
2
votes
0answers
32 views
Measures of printed map in QGIS
I created a simple map with a point and a buffer (3 km) in QGIS2.18 (and also 3.4) with CRS WGS84 UTM33.
With QGIS Composer I created the layout adding the scalebars (for 500 m and 3 km) and printed ...
3
votes
2answers
113 views
Virtual layer functionality does not seem to support memory layers
I have a memory layer loaded in the QGIS virtual layer in the data source manager. I am trying to run a very simple query:
select * from layer
Here is a snapshot:
While this works for the physical ...
3
votes
1answer
28 views
Fixing self-connect polygon in QGIS 3.2
I'm trying to clip a soil map layer and am getting invalid geometry that affects my clip result. The problem appears to be a self-intersecting polygon.
I've tried using the 'check geometries', and ...
1
vote
1answer
31 views
How can I select feature, except null values?
I want to select feature except NULL values.
In the past, when I using ArcGIS, I used 'select by attributes', and type like 'NOT "field name"=NULL'
But now, in QGIS, it doesn't work.
Just like ...
0
votes
0answers
14 views
Using alternate glyphs/stylistic set with label font in QGIS?
I am using a non-standard font for my labeling in QGIS (the font is jost*, modeled on Futura), and would like to use one of the alternate stylistic sets. It's easy to do this in Word.
Is there a way ...
0
votes
2answers
49 views
How to convert multiple shapefiles of different geometries into a georeferenced raster
I have multiple shapefiles extracted from OSM vector data, as shown in the image bellow:
How can I render this into a raster of a specified resolution? Is there a way to do that using QGIS or ...
1
vote
1answer
24 views
Clipping Vector by Custom Raster Extent in QGIS?
I have a raster image (elevation map from DEM) where I have limited the rendered elevation to only 3,500' and higher. I would like to convert the boundary/extent of this rendered image into a vector ...
2
votes
0answers
24 views
QGIS install on OSX with homebrew: “You have other linked versions!”
I have an OSX Mojave setup where I've already installed PostGIS and GDAL using Homebrew.
Now I'd like to install QGIS. I'm trying:
brew install qgis
But... I'm getting lots of warnings of the form:
...
0
votes
0answers
22 views
Installing QGIS on OSX: “QGIS requires Python 3.6” but 3.6 is already default Python
I'm trying to install QGIS on OSX Mojave from the official installer.
I have system Python 3.6 installed, as the default:
$ which python
$ ls -al /usr/local/bin/python
lrwxr-xr-x 1 me admin 44 18 ...
