All Questions
1,644 questions
1
vote
1
answer
141
views
How are the joined results different between choosing “Only keep matching records” and “Keep all records”?
I don't really understand the main difference between these two functions? What are the key differences between these two options and why are they different? Like what makes these two so different ...
- 11
1
vote
1
answer
1k
views
Importing animated GIFs in QGIS
Is it possible to import a animated GIF into QGIS? And is it also possible to georeference it, to have it on the right place?
- 45
1
vote
1
answer
1k
views
Analytical hierarchy process tool - SAGA. How to configure Pairwise comparisons table?
What is the configuration and extension (.txt, .csv ...) of the Pairwise comparisons table file requested by the SAGA AHP tool- Analytical Hierarchy Process - in QGIS? Are there examples of ...
- 233
2
votes
1
answer
421
views
Creating an Action in QGIS with multiple Expression?
I want to create an action in QGIS with multiple Expression. But unable to do so. I want to open images from two different directories with one action. Is it possible? How can I do so?
e.g.
Type : ...
- 21
2
votes
2
answers
1k
views
QGIS2 to QGIS3 plugin migration issue AttributeError: type object 'QObject' has no attribute 'connect' [duplicate]
I am trying to migrate a plugin. I have these two lines:
QtCore.QObject.connect(self.buttonBox, QtCore.SIGNAL(_fromUtf8("accepted()")), Configuration.accept)
QtCore.QObject.connect(self.buttonBox, ...
- 1,443
1
vote
0
answers
36
views
Labelling layer not from attribute fields QGIS API v2.14?
How to label vector layer with my own values that aren't stored in the attribute fields?
- 123
1
vote
1
answer
2k
views
Trying to find the Qt5 version of QVBoxLayout
Migrating a plugin and started getting the error AttributeError: module 'qgis.PyQt.QtGui' has no attribute 'QVBoxLayout' I cannot find this one in the API changes I tied using qgis.PyQt5.QtGui but ...
- 1,443
4
votes
1
answer
1k
views
TypeError: qRegisterResourceData(int, bytes, bytes, bytes): argument 2 has unexpected type 'str'
Similar question here, I tried the suggested answer but it didn't work for my situation.
updating plugin from qgis 2 to 3. qRegisterResourceData . argument 2 has unexpected type 'str'
I am ...
- 1,443
1
vote
0
answers
135
views
QGIS 2.18 - Can't get click coordinates from mapCanvas
Trying to get click coordinates from map canvas but code is not working. Newbie for Python, pyqgis, pyqt
I already check these topics but still code is NOT working
1 - QGIS 3 Get coordinates from ...
- 123
2
votes
2
answers
668
views
qgis_version_2: add layer or group of layers always on the top of the legendInterface / Insert the layer at the top of the ToC
I have a code which is adding raster layer or group of raster layers, it's working fine.
I want to know if there is a way to add layer or group of the layers always on the top of the legend Interface?...
- 942
2
votes
0
answers
106
views
How to switch on snap option in QGIS 2.18 when creating customize polygon
How to switch on snap option in QGIS 2.18 when creating customize polygon as in:
class customPoly(QgsMapToolEmitPoint):
def __init__(self, iface):
self.iface = iface
QgsMapToolEmitPoint....
- 59
1
vote
0
answers
101
views
Integrating User Defined Coordinate System into PyQGIS?
Here is my current code:
#Loading of post-wrf(raster) files starts here
crs = 'USER:100000'
QSettings().setValue('/Projections/defaultBehaviour', 'useGlobal')
QSettings().setValue('/Projections/...
- 55
1
vote
1
answer
53
views
Counting features within other features
I've several files composed of elements like the one below which I'm trying to make sense of (essentially a very simple microtopography study).
I've vectorised the image with lots of separate lines ...
- 415
4
votes
1
answer
1k
views
Filter vector layer by searching through complete attribute table - limitations and improvements
In a case were I have a shapefile with a lot of attributes (predominantly text), also I don't have any information about the structure and I don't have any idea in which attribute I have to search/...
- 4,474
3
votes
1
answer
207
views
Counting number of roads between two points using QGIS
I use QGIS 2.18 and I have a point shapefile of many animal locations and a shapefile of roads.
I want to use QGIS to tell me how many roads are between each pair of animal locations.
So, basically ...
2
votes
1
answer
395
views
Inherited values between polygons in QGIS [duplicate]
In this project, I have three polygons, see the image below
'Polygons_From', includes input attributes, i.g. "Value_1", "Value_2", "Value_3", and $area for each quadrate ...
- 34k
2
votes
0
answers
179
views
Inverting shapefile in QGIS 2.18?
I asked a question earlier about how to invert my file "hydropolys.shp" from a vector of ocean and seas to a vector of land and got sent to here, but I am experiencing issues where using the "...
- 53
2
votes
1
answer
461
views
UNION two LEFT JOINs as Virtual Layer in QGIS
In QGIS 2.18, there are two layers, e.g. "Locations" and "Connections"
"Locations" has values
Id | Dimension
---------------
1 | 4
2 | 8
3 | 2
"...
- 34k
8
votes
3
answers
1k
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'...
- 799
1
vote
0
answers
29
views
Saving individual figures in Print Composer in QGIS 2
Can anyone tell me how to save individual figures in QGIS print composer that I can later go back and edit?
Do I have to create a new print composer for each figure?
I am using QGIS 2.18.9.
- 11
1
vote
1
answer
57
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 ...
- 13
1
vote
1
answer
505
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?...
- 11
0
votes
0
answers
95
views
Converting QGIS 3.6 Templates for use in QGIS 2.18?
How do I convert QGIS 3.6 Templates for use in QGIS 2.18?
I have found plenty of stuff on converting the opposite way around.
- 101
9
votes
2
answers
1k
views
Adjusting flow map styles in QGIS 2
In one project, I am trying to adopt marvellous styles for flow maps created by @underdark.
At this moment I have the following output
Shapefile was created with the usage of Flow maps (Oursins) ...
- 34k
2
votes
0
answers
259
views
Updating set of attributes on vector layer from .csv table?
I have over 1,000 records in a .shp file, all with a unique ID field (LINKID), along with many other fields containing data (TXTFLD1, TXTFLD2, INTFLD1, INTFLD2, etc).
These records have been copied ...
4
votes
1
answer
682
views
How to update the Layer Tree View after changing the color ramp in PyQGIS?
After changing a raster style/color ramp (wich is working properly to define the class colors and values) using:
layer = processing.getObjectFromName('NDVIrec')
provider = layer.dataProvider()
...
5
votes
1
answer
1k
views
Geopackage - select on geometry column returns null
In DB Manager in QGIS 2.18.26
I want to select geometries in geopackage table.
The returned geometry column is null but the source layer can be loaded as a geometry table in Qgis and i can read the ...
- 1,096
4
votes
1
answer
2k
views
PyQGIS: "for" loop with nested "if ..elif ..." condition
I want to update an existing field according to another, it means the equivalent of a CASE WHEN .... THEN ..... ELSE .... END in SQL , but I want to know how to write this same update in Python for ...
1
vote
1
answer
111
views
Why "Unique ID fields" is not saving its value in Dissolve algorithm in Graphical modeler?
I am working on my project in QGIS 2.18 through Graphical modeller and using some basic algorithms for polyline objects.
However, I do not understand why specification for Dissolve algorithm cannot ...
- 34k
2
votes
1
answer
604
views
QgsMapToolEmitPoint.canvasReleaseEvent not firing with SHIFT modifier
I've created a plugin that implements a Map Tool. It captures mouse click events, which works fine. Now I want to capture Shift+Mouseclick. This doesn't work at all, while Alt+Mouseclick and Ctrl+...
- 171
1
vote
1
answer
248
views
Using GRASS 7 in QGIS 2.18 on MacOS
Does anybody found a way to use GRASS 7 in QGIS 2.18 under MacOS?
QGIS 2.18.19-2 is the latest version packaged with GRASS 7. For many reasons, all the following versions been have packaged with ...
- 476
1
vote
0
answers
60
views
pyqgis: using gdalogr:rastercalculator not working
I have an Int16 - 16 bit GeoTiff and would like to do a simple calculation.
Using the GUI in QGIS (raster calculator) it works without problems. The expression in the raster calculator is: ...
- 545
8
votes
2
answers
3k
views
Export as SVG with path / polygon IDs
I imported two layers to my Project (one is a shapefile from natural earth, the other is built out of lon/lat Points in a csv-data-file) QGIS fits the two graphics perfect together. Now my goal is to ...
- 83
3
votes
2
answers
340
views
Calculating tortuosity in QGIS 2.18.27
I am struggling on how to calculate tortuosity in QGIS. My data includes numerous lines (the mapping of animal trails) I have tried calculating tortuosity with the field calculator but had no luck is ...
- 651
2
votes
0
answers
153
views
Count the number of points of a multipoint-feature [duplicate]
I try to use the fieldcalculator in QGIS 2.18 to count the number of points of a multipoint-feature. Is it possible?
- 21
1
vote
0
answers
93
views
Difference between DEM raster in QGIS 2.18 and 3.4.4 [duplicate]
I came across a really strange problem.
Untill today i always worked in QGIS 2.18. Now i wanted to upgraded to 3.4.4 ( it was already downloaded but hadn't used it yet)
When opening my QGIS ...
- 166
3
votes
3
answers
708
views
Automatically populate r.reclass rules based on table values
In QGIS I have a raster map showing land, snow and cloud zones, having resp. pixel values 1, 2, and 3. I extracted the mean altitude values (in m) of each zone on the basis of an underlying DEM and ...
- 111
0
votes
1
answer
644
views
KML polygon rainbow filled colors is showing only as simple color?
I draw filled color contour in Surfer application
I imported this file to Google Earth as .kml file
There is no problem so far
I tried to import the same file to QGIS 2.18.28
But the colors is not ...
- 1
1
vote
1
answer
172
views
QGIS 2.18: Import Result Table of a query into QGIS as pointlayer
I have a query which outputs a table with an unique nodeID and x-,y-coordinates.
How can I import this query result table into qgis as an point-layer?
I have tried it with the DB-Manager (see below)...
- 725
0
votes
0
answers
42
views
QGIS 2.18 Workaround minidump in C [duplicate]
I have an input POINT-layer with lots of features in it. What I am trying to do is to calculate the azimuth for two features. And the way I am doing this is the following:
geomFrom = (...).geometry() ...
- 725
0
votes
1
answer
702
views
QGIS - online Bing basemap shifts when map is exported as a PDF [duplicate]
Using QGIS 2.18 “Las Palmas”
Created a map to print using the “New Print Composer” extension.
When working on this all polygons are perfectly in place.
Once the map is saved as a PDF/Image the ...
0
votes
0
answers
181
views
Difference tool becomes unresponsive and causes QGIS (2.18.24) to crash
I'm trying to find the difference between two layers (the first is a manitoba wide shapefile and the second is a layer that narrows down the water bodies of manitoba selected from another canadian ...
- 1
2
votes
2
answers
789
views
How to remove the boundaries of a Polyline?
I have a polyline. I want to delete outside boundaries of that polyline. I achieved it by splitting the features of that polyline and selecting/deleting the outer lines/boundary.
I'm thinking, is ...
- 772
0
votes
0
answers
101
views
using multiple mapbox wmts baselayers with dififerent labels in QGIS composer
I have created two basemap layers in mapbox.
https://api.mapbox.com/styles/v1/akrystos/cjr1epzf905a32sqhkwvjl5i7.html?fresh=true&title=true&access_token=pk....
- 1
0
votes
1
answer
141
views
The new version of qgis (2.18.20) no longer scales maps in the print composer
I've used various versions of qgis to make maps and never had a problem scaling them until now.
My system updated, including my version of qgis which has the scale option but doesn't apply it to the ...
3
votes
0
answers
492
views
Unable to compute intersection between two polygons using PyQGIS?
I have two polygons in different layers. I am trying to find the intersect between the two polygons. Below a figure showing my test case. I initially wanted to find the intersect between the green ...
- 31
1
vote
1
answer
2k
views
Merging TIFF files using QGIS?
I have around 1200 tiff files (example below), and corresponding .tfw files and .aux files with sonar data that I'd need to merge into one file and I'm struggling to do so.
I browsed some topics ...
- 408
1
vote
1
answer
105
views
Creating label coordinates in a virtual columns in QGIS 2.18
I'm working from a database (PostgreSQL/ PostGIS).
I created a view in QGIS of joined polylines from one table with the ST_union function.
I want to label this polylines in QGIS. So, I created 2 ...
- 13
1
vote
1
answer
162
views
Line first,last node distance along another line QGIS
I am using QGIS 2.18.6 . I have created two line layers. First layer "testroad" with long line (road). Second with short lines along,near road. I would like to know distance of first and last point of ...
- 61
3
votes
1
answer
684
views
Assigning function to a key in QGIS Plugin
I have trouble assigning function to a hotkey in my plugin. I have a class that does things with a mouse click. I'd like to assign another function to a keyboard key or sequence. I've tried two ...
- 372