Questions tagged [qgis]
QGIS is a cross-platform GIS application licensed under the GNU General Public License.
-1
votes
0answers
11 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 ...
0
votes
2answers
32 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
9 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 ...
0
votes
0answers
14 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 ...
0
votes
1answer
41 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
12 views
Replicating the Layers Panel in my app, with sub-layers
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
24 views
Removing inner border of merged polygons using QGIS?
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
16 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
21 views
Cannot convert 'nan' to double, QGIS Field Calculator
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
84 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
21 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
18 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....
-1
votes
1answer
42 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
2answers
75 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
22 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
21 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
15 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
48 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
40 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
22 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
36 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
43 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
25 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
49 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
13 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
30 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
103 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
29 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
13 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
41 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
22 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
21 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 ...
0
votes
0answers
16 views
Kernel Density Estimation Weighting Factor
I dont understand where is this weighting factor coming from, does it need to be in the quakeLyr in the attribute table named with "mag" or?
##Now, we can run the kernel density estimation algorithm ...
0
votes
0answers
22 views
SDO Oracle Table not recognized as Geometry in QGIS
I can connect to the Oracle Database with QGIS but spatial table/layers are not recognized as such.
I have read the following in the QGIS documentation:
Normally, an Oracle Spatial layer is ...
1
vote
0answers
29 views
Changing the field colour/design on a QGIS 3 QT attribute form?
I have problems with changing the physical appearance of a custom attribute form (QGIS 3, Windows 7).
A custom attribute form can be designed, for use in QGIS, using QT / QT Designer. In QT Designer ...
3
votes
1answer
35 views
Cheapest path through polygons and lines from point to point
I want to find the cheapest path or the least cost path from one point to another point. The points are part of a vector map and do not lie on a network. All features being part of the map have ...
3
votes
1answer
37 views
Central deployment of startup.py in QGIS
In QGIS 3 on Win10 we use a startup.py script for setting up e.g. database connections and a couple of other things, residing in C:\Users\me\AppData\Roaming\QGIS\QGIS3
What we are after is to ...
2
votes
1answer
39 views
Get OGR driver Name for QGIS VectorLayer
Is it possible in the Python script to get the name of the OGR driver (for example, "Esri Shapefile" or "MapInfo File") for the QGIS vector layer?
__
QGIS 2.18
2
votes
2answers
144 views
Apply Line Pattern Fill to LineStrings?
I am trying to print out a network map using black/white hatching patterns, similar to Black/white hatching pattern fills in QGis but for Lines. Is there some trick I can use?
0
votes
0answers
12 views
XML to TIFF raster and zonal statistics in QGIS
I was sent several XML files of a flood model's peak extent that works fine in ArcGIS, I need to use zonal statistics, and I don't have that available in my workplace's ArcGIS subscription, so I need ...
1
vote
0answers
9 views
Cannot find Grass7 folder in QGIS 2.18 content folder
I have freshly re-installed QGIS 2.18.28 in the prescribed order.
I was under the impression Grass7 in included in one of the install packages.
But when trying to point QGIS to the grass7 folder under ...
1
vote
1answer
46 views
Raster Volume Returning Wrong Volume
I have a clipped surface using Washington State Plane North (feet) added to a QGIS project using the same CRS. I am trying to calculate the area under this surface (a dirt pile) using SAGA Raster ...
1
vote
1answer
40 views
How to split vector layer in PostgreSQL/PostGIS
QGIS has this nice tool to Split a layer into multiple layers based on one attribute and create a new layer for each unique value within that attribute.
Is this also possible using PostgreSQL/PostGIS?...
