Questions tagged [qgis-3]

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

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2
votes
0answers
47 views

Error while exporting geometry to CSV with MMQGIS

I am importing a DIVA-GIS shapefile into QGIS. It has a lot of polygons on it. My aim is to group different groups of polygons together and dissolve their internal boundaries so that I end up with ...
2
votes
1answer
28 views

Adjusting brightness/contrast for XYZ Tile Data

Is there a way to adjust brightness and contrast for XYZ tile data in QGIS 3.4? Specifically, I'd like to adjust the settings for the Google Imagery Hybrid XYZ tile. I'm running QGIS on Windows 10.
3
votes
0answers
42 views

“Bring All to Front” is missing in QGIS 3

I am using QGIS 3.4 and 3.10 and a plugin's window ends up hiding behind the canvas. In QGIS 2.10 I had the option "Bring All to Front" to bring all windows to front. Is there an alternative for it ...
2
votes
0answers
33 views

System couldn't find given path while running v.split

I'm trying to run the Grass Tool v.split and get the following error message: the grayed outline in German translate to "The System couldn't find the given path" The .exe-files of the grass Tools ...
2
votes
1answer
66 views

Maximum and mean value is different in Python than QGIS 3.6

I read a Landsat-8 TIFF file using Python Rasterio to compute the max and mean using the following code: path = "LC08_L1TP_115036_20181025_20181031_01_T1_B7.TIF" test = rasterio.open(path).read() ...
1
vote
1answer
23 views

Tool for adding raster values to vector z axis

In ArcGIS, there is a tool called "Interpolate Shape" which takes a vector layer and underneath a raster. Then it adds the raster grid values to the vectors z-coordinates. Is there a tool in QGIS ...
3
votes
2answers
54 views

Set default style for QGIS Composer Items

When creating a Composer Layout in QGIS, it is useful to add multiple items such as text boxes, shapes and arrows. Once I have formatted an item (eg an arrow line) is it possible to set it as a ...
2
votes
1answer
36 views

Creating a Line feature in PyQGIS QGIS 3.x

In QGIS GUI, a line feature is created from this icon 1.jpg How to Create a line with a fixed distance from a vector layer in python console. This my example: from qgis.core import * from qgis....
2
votes
1answer
56 views

How to connect a QgsMaptool with a widget pushButton

I've write this QgsMaptool above and it works great in python console imports... class obsCreator(QgsMapToolEmitPoint): def __init__(self, iface): self.iface = iface self.canvas ...
5
votes
1answer
85 views

Rule-based labeling with optional second field

I need to label some polygons with 2 fields using only one label: The first being a field in the attribute table named "Bio-Code" the second one being optional if a cell in the field "BBT-Code" is ...
1
vote
0answers
39 views

QGIS wrong measurments on Google satellite images

I am new to QGIS but I understand the basic principles. I'm working with QGIS 3.8.3 on OpenSUSE Tumbleweed Linux using the KDE environment. Still trying to figure out QGIS, I'm opening a brand new ...
2
votes
0answers
33 views

Using Python code from QGIS 3.x Graphical Modeler in console?

I want to use "Join Attribute by Location (summary)" processing algorithm in Python console of QGIS 3.10. After design my algorithm process (join sum of field name "abc" form layer 2 (point layer) to ...
6
votes
1answer
257 views

Extracting features with equal field value using graphical modeler of QGIS

Is it possible to automate the following procedure with graphical modeler in qgis 3.4 or is it easier to perform such action with a python script using PyQGIS? Identify a feature (a line) in a vector ...
2
votes
1answer
49 views

Zooming to specific layer using PyQGIS

Using PyQGIS with QGIS 3, I am trying to zoom in a specific layer but I have not succeeded. He tried several answers but it doesn't work for me. Either it gives me a mistake or it does nothing to me ...
0
votes
2answers
65 views

Which versions of python3 can we use with current QGIS3 version

Mac OS 10.04, QGIS 3.10. I have been a way from QGIS for a while and I am now setting up a "new" Mac and having my usual battle with python. Great to see that we now have signed package for QGIS but ...
4
votes
1answer
41 views

Interpolation with Breaklines- How to Apply Breaklines as Surface Discontinuties

I can't seem to get Breaklines to behave as defined here with the QGIS 3 (3.10 today) built-in Interpolation (TIN or IDW) . In my case I am preparing a subsurface structure map with geologic faults (...
1
vote
1answer
53 views

Designing small letters under words in QGIS

I want to design small letters under words in QGIS when I designed the labels (attach picture). Is there any way to do it?
2
votes
1answer
49 views

Designing text in QGIS

I want to write cubic meters in QGIS 3, I searched a lot but I didn't find any instructions. Is there a way to write cubic meters as m³?
1
vote
0answers
51 views

How to fill a field with comboBox.currentText()

Basically, I want to create a widget plugin (QGIS 3.x) in which any user can choose a standard text from a combo box and, after press a ok button, enable a layer for editing and calls the add feature ...
1
vote
1answer
45 views

Select by location tool Vs layer.getFeatures(QgsRectangle(xmin,ymin…)))

I can't make sense of the difference between: QGIS Select by location tool (Vector->Research tools->Select by Location") which gives the correct result :7 records match the extent: Creating a ...
4
votes
2answers
132 views

Automating vector data entry in QGIS

I have a vector contour data(polyline). I want to add values to each contour lines. Means I want to digitize my contour lines with proper values. Those values are with me in a paper. I'm adding those (...
0
votes
0answers
72 views

Unable to load PostGIS-table for QGIS on MacOS Catalina

I just updated to the QGIS 3.10 release under MacOS Catalina. In 3.8 I had no problem using PostGIS-data. When I now try to load the same PostGIS-layer in 3.10 it fails. When testing the connection, ...
1
vote
1answer
47 views

Persistent data for QGIS plugin

I am writing a qgis plugin to display spectral information stored in a geodatabase (Spectre Viewer). For this, I need calibration factors to get from channel values to energies. I want the end users ...
2
votes
1answer
215 views

Deep Learning in QGIS: installing Tensorflow

I am trying to install tensorflow (with or without GPU support) with the keras API in the QGIS 3.4 LTR python 3 environment but without success. I do have a working install of tensorflow-gpu that I ...
2
votes
0answers
41 views

Qgis2web mouse cursor changing symbology

Hovering mouse cursor over polygon on QGIS created webpage changing symbology. I´m have exported webpage from QGIS, thru qgis2web plugin. On settings I have checked "Highlight on hover". When I move ...
4
votes
2answers
175 views

Adding coordinate constant to file in QGIS

i have a dxf file where the coordinate constants has been dropped from x coordinate. For example my real coordinate should read +2954632 but instead it reads as 54632. How can I add the 29 000 00 in ...
2
votes
1answer
36 views

QGIS polygonize issue: GDAL DLL load failed

I am using QGIS Desktop 3.10.0 and I have some issues with the polygonize tool. When I run the polygonize tool, a warning shows up saying that there is an “Import Error: DLL load failed” (see Figure 2)...
2
votes
1answer
37 views

Sort or add Rank within QGIS 3 model

I have the following function in order to add a sorting value to a layer: array_find( array_sort( array_agg("field")), "field") This works fine if I use it through the calculator within the ...
3
votes
1answer
39 views

Getting list of layers when opening a QGIS project on a standalone app?

I am trying to make a standalone QGIS app to read a .qgs file for rendering an image based on the vectors using LayoutManager. The problem is that when I try to print project.mapLayers() I get an ...
1
vote
0answers
20 views

Add help tab in plugins from the toolbox

Is it possible to add in QGIS 3 (Python Script) a help tab on the plugins created for the toolbox as it was in QGIS 2? Looking in the API I found the parameters helpString that will be deprecated in ...
2
votes
1answer
45 views

PermissionError : [WinError 32] --> how to close raster file handler after use?

I created a function where I access to a Raster folder and get all files CRS for Rsubdir, Rdirs, Rfiles in os.walk(Rrootdir): for Rfile in Rfiles: ...
2
votes
0answers
43 views

How to install GDAL version 3.0 on Windows in order to generate GeoPDF with Qgis 3.10? [duplicate]

I am very enthusiastic to create some GeoPDFs using the new version of Qgis 3.10 on Windows. Unfortunately, using the OSGeo Installer, the newest gdal package version proposed is 2.4.1, which is ...
2
votes
1answer
26 views

Optional variable (with default value) in custom function

Is it possible to use an optional variable (value2) like ... @qgsfunction(args='auto', group='Custom') def my_test(value1, value2=True, feature, parent) .... in a custom function? Using QGIS 3.8 ......
1
vote
0answers
23 views

QGIS: clip raster by mask with .xyz?

I have a DEM in .xyz format and a polygon. I tried to use the "Clip raster by mask" tool to Clip the raster but it doesn't work. The error message just said "couldn't create layer ... there are more ...
2
votes
1answer
83 views

gdal_calc raster calculcator : “any” syntax

I'm trying to combine 2 raster layers using gdal_calc in order to use them in QGIS 3.8. One of the condition that has to be met could be translated as "if the value of raster A is 1 and the value of ...
3
votes
1answer
58 views

Regular expression delimiter for text file in QGIS 3

I have a text file containing coordinates but also comment lines such as : #file description #description point 1 id1 X1 Y1 Z1 #description point 2 id2 X2 Y2 Z2 and I want to import this file in ...
1
vote
1answer
40 views

Raster layer statistics QGIS 3.4 doesn't give information about pixel count

I created a plugin in QGIS 2 AND I used the qgis:rasterlayerstatistics , I could get the 'COUNT' information : pixels number, but when I migrate my plugin to version 3.4 I found out that this ...
1
vote
1answer
23 views

What method is used to assign values to raster projected raster cells in QGIS?

I have a raster in GCS NAD83 with a resolution of 0.008333 (see properties below) I want to project it to NAD83 /Conus Albers with a new pixel resolution of 2500m. Can I do this using the save as ...
2
votes
0answers
25 views

Selecting features of one layer based on another layer

I have a polygon layer A, then a new layer is created by applying minimum bounded boxes algorithm and then I selected those features in which height and width of bounded boxes is less than 150 and ...
2
votes
1answer
74 views

Moving point A to point B with attributes using QGIS

I have an A layer containing points with a XX attribute. I would like to move (on points A) the points of a layer B with the same XX attribute as A. There is no notion of distances (from a few cm to ...
2
votes
0answers
37 views

Adding raster layer from WMTS URL using PyQGIS

I am trying to add a WMTS raster layer in QGIS 3.8 using Python (for my plugin). I have found this Loading Layers - Raster in the documentation, but I cannot make it work. I tried this: ...
1
vote
1answer
54 views

Plotting points using AusMap plugin QGIS v3?

I am trying to plot infrastructure points from the AusMap plugin but it does not align with my current CRS. The points are in GDA2020 - when I change my basemap to this it still does not align. I am ...
1
vote
1answer
42 views

Setting output path to PostgreSQL in processing function of PyQGIS

I am studying PyQGIS to analyze gis data. I want to set output path to PostgreSQL in QGIS 3.8 but I have no idea... According to processing.algorithmHelp('qgis:simplifygeometries'), only show OUTPUT: ...
1
vote
0answers
38 views

QGIS Memory Usage Eventually Crashes Program

I am using the long-term release of QGIS (3.4.12). When I first start the program, it takes up about 625K of memory. After I have been working with it for several hours, the memory usage often ...
3
votes
0answers
42 views

Joining attributes from points to polygon

I am working with two shapefile, polygons and points. These shapefiles do not overlap and have different attribute values. The point layer contains data that I want to join to the beginning and end ...
3
votes
1answer
86 views

Keeping lines in PDF after export in QGIS 3.4?

I have regularly this problem: when I export lines from QGIS to Illustrator with a .pdf (or even .svg), my lines are destroyed in several lines. Is there a way to keep my lines unbroken?
1
vote
2answers
55 views

PyQGIS Close Layout Window

I have a script that iterates through layer subgroups in QGIS 3.6, opens a layout with the with the same name as the subgroup and exports a PDF. What I am struggling with is to close the active layout ...
4
votes
1answer
74 views

Create boundary polygon in QGIS

Given a set of polygons of property boundary's where there is a field "Network" which shows us which network a property is in, I need to create a tight boundary for each network -it can be multipart ...
3
votes
0answers
53 views

Error while running batch processing in QGIS 3

I have built a straightforward model in the Graphical Modeller in QGIS 3.4 to select features by expression and then save the selected features to a new shapefile. It works when running singly but ...
2
votes
0answers
30 views

Point Displacement in MapServer

In QGIS symbology controls there is a "Point Displacment" option for offsetting points that are close visual clarity. Is there a similar control for MapServer?