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Questions tagged [qgis-3]

for questions specific to the 3.x series of QGIS.

0
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0answers
3 views

GRASS v.surf.idw in PyQGIS

I have a point shapefile I am trying to run the GRASS v.surf.idw tool on in python. Here is a link to the data: https://github.com/tanyahelena/qgis_data I have a short script which runs. I don't get ...
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0answers
8 views

Standalone error using Python 3: layer.isValid is False

I am trying to create a standalone application using Python 3.7 and QGIS3.6. on Windows 10. I have installed QGIS using the OSGEO4W method, in the 64-bit flavour. My issue is that when I try to load ...
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0answers
8 views

Connect optimal path and optimal destination [on hold]

I have the following problem which can be solved in 2 stages: The first stage is to calculate the least cost path for transporting the produce from a pixel on the field to the edge of the road, for ...
1
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0answers
17 views

Is it possible to insert a string without ' ' in the modeler?

QGIS 3.4.7 I have a lot of Models where there are some string inputs. In all of them, I have to enter the string between quotation marks ''. I understand the meaning and pourpose of them in any ...
1
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0answers
6 views

SourceCrs TIN Error

I am trying to use the TIN interpolation to interpolate conductivities between a vector layer in QGIS 3.4. and I always get this error: Traceback (most recent call last): File "C:/PROGRA~1/QGIS3~1.4/...
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0answers
9 views

Is it possible to open a raster or raster dataset contained in a file geodatabase with QGIS 3.X?

I know that it is possible to extract vector data from .gdb's. I have found some similar questions here on StackExchange, but they were either not exactly what I was looking for or really old where ...
1
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0answers
8 views

Feature Count for Categorized Layers with the Atlas function of Print Layout in QGIS 3

In QGIS, is it possible to count the features of each class in a categorized layer where the features being counted are limited to those that are inside the current atlas feature? I have tried ...
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0answers
26 views

What signal can be used to get the selection change on a feature?

Right now I am using: self.iface.mapCanvas().selectionChanged.connect(FunctionThatReactsToTheSignal) But this one sends two signals, one for the deselection of the previous feature and one for te ...
1
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1answer
14 views

Append Symbol Layer PyQGIS3

I am updating a QGIS2 plugin to QGIS3. The following code in PyQGIS2 works: association_symbol = QgsSymbolLayerV2Registry.instance().symbolLayerMetadata("ArrowLine").createSymbolLayer({ ...
2
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0answers
27 views

QGIS 3.6 picture in ui form (Qt5 Designer)

I'm facing trouble with display a picture in a ui form based on a field (path). With the autogenerate form it works but when I try with a personalized form I cannot see the picture. I tried with a ...
1
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0answers
19 views

Hide columns in QgsAttributeTableView with Python

I use this code to initialize QgsAttributeTableView and hide some columns in it in my custom widget: def __init__(self, layer, canvas, hidden_columns, cache_size=5000, parent=None): """...
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0answers
35 views

How to create equidistant points along lines (network)?

I am trying to create points at every X meters along a set of lines that represent a network. As suggested in QChainage doesn't place points evenly along dissolved lines I managed to this ...
2
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1answer
44 views

Smoothing polygons in QGIS? [duplicate]

I vectorised an image and all my polygons have extremely jagged edges. What is the best way to smooth these polygons?
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0answers
21 views

Python Floating Point Error when using SCP plug-in (QGIS 3.6)

I receive a python error every time i try to save a temporary ROI to training input in the Semi-automatic classification plug-in in QGIS 3.6. I'm unable to add any training ROI to training input. ...
1
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0answers
9 views

An internal QGIS plugin repository shows available plugin (3.1) version predating the installed version (3.2)

The metadata file is updated and the ui and resource files were compiled. The .xml file is also updated. Where else does QGIS store the plugin version? The plugin works just fine but the 'installed ...
0
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1answer
38 views

QGIS transparency as 4th input layer

I have a file that contains four rows. The first row indicates the longitude, the second row indicates the latitude, the third row indicates the colour of a specific longitude and latitude and the ...
1
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0answers
12 views

Value Map Form Widgets in QGIS 3.x

I am using QGIS 3.6 and I have a list of cities and zipcodes for my county, in my geopackage address layer I have a field called zip I tried to set up a value map with city names in the "description" ...
1
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1answer
25 views

Apply color ramp to (QgsSingleSymbolRenderer) Simple marker

I'm using a QgsSingleSymbolRenderer to display various points and lines etc for a Line geometry. I have a Single symbol symbology to display the last vertex as a: Line > Marker line > Marker &...
0
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1answer
30 views

Create WFS-connection in QGIS 3.4

I'm adding a WFS-Layer to QGIS 3.4. Can somebody tell me if the URL http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap is a correct adress. I need to connect to this server. Are there any special settings ...
1
vote
1answer
20 views

Expand or Collapse Layer Groups in PyQGIS3

PyQGIS2 has a function to expand/collapse a layers with a subset of styles in the Layers panel as follows: self.iface.legendInterface().setLayerExpanded(self.segments_layer, False) I know that in ...
3
votes
1answer
26 views

Data source not found when opening .qgs file

I am using QGIS 3.6.1 with the new geopackage (.gpkg) format. When some of my co-workers open my .qgs-file, QGIS (same version as mine) does to not find the data source for most of the layers. ...
3
votes
1answer
140 views

Change to uppercase all tables data [on hold]

I have 190 layers in shape file with attribute filled in lower case. I want to change data of all tables in uppercase using Qgis. I am able do to do it one by one using upper in expression. How to ...
0
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1answer
24 views

.tif image (made in QGIS 3) imported into Google Earth Pro is blank/has no symbology options

I am trying to import .tif images into Google Earth Pro, which have been created in QGIS 3. The image has two colours, black and white, with only two values, 1 and 0, which was represented by each ...
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0answers
20 views

AttributeError: 'NearestNeighbour' object has no attribute 'dlg' [on hold]

I am learning to make my first python plugin named NearestNeighbour(different from the one we have in QGIS3, name are coincidentally same) which take two vector layer. With the help Qt Creator I was ...
1
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0answers
13 views

Is there an API to tell which feature is currently being a target of “identify” tool?

I want to make a plugin that calculates some property of a selected feature. I can use "select feature" tool and then use l=iface.layerTreeView().selectedLayers()[0] f=list(l.getSelectedFeatures())[0]...
1
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1answer
18 views

Parsing an input parameter to gdal:rastercalculator formula in QGIS 3.6 Python script

For training purposes I'm writing a QGIS 3.6 Python script. The script takes as inputs a raster layer and band, and three float numbers (refmult, refadd, sunel) and computes a simple formula: ((layer@...
1
vote
1answer
46 views

Set label precision with QgsRendererRangeLabelFormat class

I'm trying to control the number of decimal places represented for a layer in my project. I can do this in the symbology tab like this: I want to do this in PyQGIS. Here is an example of how I would ...
1
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0answers
15 views

How to update datasource of handle bad layer with Python console in QGIS 3.4

How do I update the datasource of file project in QGIS, for example myexample.qgz from Python console? What is the command needed, or scripts standalone? For example: layer = iface.activeLayer() ...
1
vote
1answer
31 views

Renderer and Rules in QGIS

This question is somewhat involved, so please bear with me. I am updating several plugins from QGIS 2 to 3. Most of them include accessing spatialite databases and creating layers from the various ...
-1
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0answers
24 views

Geochemical map of sample data using QGIS [closed]

I have points with tin concentration values. I want to create a geochemical map with QGIS 3.4. Any URL link or idea how to do is welcome?
1
vote
1answer
25 views

Area Value not getting reflected in attribute Table using PyQGIS?

I have a WardBoundary.shp file in my project. I need to find the area of each polygon ( representing different wards).With the help of this comment on Adding Area column in Polygon layer using PyQGIS?,...
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0answers
8 views

Reproject Sinusoidal Big Raster to EPSG 4396

Today reproject MODIS Sinudoidal to EPSG 4396, in my older GDAL and Qgis 2.14 easy. But today no understand why not and sending this bugs!! david@dummy13:/mosaiced_tiles$ gdalwarp -s_srs "+proj=sinu +...
-1
votes
1answer
46 views

Adding Area column in Polygon layer using PyQGIS? [closed]

I have a WardBoundary.shp file with Polygon Features in it. I have to calculate the area of each Polygon and write into attribute Table. I can do manually by using '$area` but I need to automate ...
1
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0answers
26 views

Error in Raster/Merge tool

I am completely new to QGIS. I am on a Mac using OS 10.13.6. I have installed QGIS 3.6, and installed Python 3.6.8 per install instructions. I opened a terminal window to check python install: ...
0
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0answers
20 views

Create a map grid with CRS EPSG 4326 [closed]

I need to create a map grid in the QGIS 3.4 print layout. I'm using a map with CRS 4326 and created a map item in the print layout view. I created a grid with the appropriate interval units and ...
1
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0answers
21 views

Where is “Nearest neighbour analysis” tool in pyqgis documentation?

I have a group of point features for which I want to run the Nearest neighbour analysis using python. The problem is that I cannot find that function in the documentation. The closest I got was: ...
2
votes
0answers
16 views

Merge Vectorfile Outputs from Model Batchprocess in QGIS

I have written a model in QGIS 3.6 that allows to vectorize the outlines of raster layers containing measurement data. I run this model as a batch process to vectorize several field outlines in one go....
0
votes
1answer
27 views

Creating Vector Attribute Field with Raster Value in QGIS

I want to create a new attribute field contains data coming from a raster in a vector file. I tried the GRASS v.drape tool but the analysis did not create any new field in shapefile. Also, I tried the ...
0
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0answers
12 views

GRASS r.sun returns “ERROR: insol_time and incidout are incompatible options”

I'm trying to measure irradiance on a DEM using the r.sun tool in QGIS 3.6. I have grids for the elevation (EPSG:32735 - WGS 84 / UTM zone 35S), the slope and aspect (EPSG:4326 - WGS 84). I've tried ...
2
votes
1answer
47 views

Sort inputs parameters in QGIS modeler

I created a model in QGIS 3.6 with three inputs parameters (two vector layer and one vector field). When I run the model, the inputs are not sorted in a correct way: the vector field is requested ...
-1
votes
0answers
44 views

Plugin Not Installed in Qgis

I am using QGIS3.4 and want to in instal XYZ Tile plugin. this plugin(XYZ tile Ver2) released today,but not installed successfully. Plugin Link: https://plugins.qgis.org/plugins/tiles_xyz/ can anyone ...
1
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0answers
22 views

Getting rectangle coordinates created in custom QgsMapTool Class of PyQGIS?

I am developing a QGIS (QGIS 3.6) dockwidget plugin where the user creates a rectangle (boundingbox) on the canvas and the plugin sends the rectangles coordinates attached to a HTTP request to my FME ...
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votes
0answers
30 views

Any3D objects not rendered?There is a compatibility issue with QGIS 3D view. You need to close QGIS 3d VEIW(S) AND RESTART QGIS TO USE THIS PREVEIW [closed]

I am using QGIS 3.4 version it showing error message or warning while using with plugin Qgis2threejs. I need know how to remove the 3D view option from QGIS.
0
votes
1answer
22 views

Aligning Cartosat-2 Image?

Recently our company purchased Cartosat-2 Image from NRSC. Our Mining Lease area Boundary is not aligning with Image.It is around 100 meter offset.We are using QGIS 3.4.Spatial reference of Cartosat-...
6
votes
1answer
73 views

Changing column order in QGIS?

There was a table manager plugin in earlier versions I can't see anymore. Is there a way to achieve this in QGIS 3.6?
2
votes
1answer
41 views

Snapping to sketch' vertices while editing in QGIS?

I'm trying to digitize buildings in QGIS and encountered a problem: after digitizing several vertices in a sketch, I want to place my final vertex in accordance with the first one - i.e 'square and ...
0
votes
0answers
26 views

Converting GeoTIFF file into vector file using QGIS? [closed]

I have a GeoTIFF file and what I want is to convert this raster file into a vector file. I've tried several times, but it didn't work. My aim is to get a file to create a terrain analysis
2
votes
1answer
38 views

QGIS 3.4 using pygis for deleting colomns

I am currently building a model for importing and preparing multiple data by merging shapes and joining tables. Almost finished with the model, but I haven't found a useful tool for deleting certain ...
2
votes
1answer
22 views

Control feature rendering order in QGIS with plugin

I am trying to find the python equivalent of enabling the checkbox for controlling the feature rendering order based on an attribute of the features of a layer (see below screenshot). I want to base ...
1
vote
1answer
29 views

Update QGIS Canvas while debugging

I am upgrading some QGIS 2 plugins to QGIS 3 and need to do some debugging. It appears that the canvas does not update until the code stops running, regardless of any calls to self.iface.mapCanvas()....