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Questions tagged [qgis-3.0]

For questions about Version 3.0 of QGIS

3
votes
2answers
112 views

How to automaticaly create a buffer for a line in QGIS

I am creating some lines, and I would like to add a 500m buffer around thoses lines. But i need this buffer to automaticaly change if i modify my line around. Is there any solution to this?
0
votes
0answers
13 views

How do I change 'Coordinate Display' for a project, programatically?

From the user interface in QGIS, I can change the coordinate display (unit) for a project by going to: Project > Properties... > General (tab) and under the Coordinate Display section can ...
0
votes
0answers
15 views

Scale seems incorrect in QGIS 3.4.3 for Mac in the editing window

I've been working on a map for a few months now and decided to export it in Composer to see how it's rendering out elements like creek labels when I noticed the exported scale was vastly different ...
0
votes
1answer
33 views

Automatic calculation field based on line modification within QGIS [on hold]

I have a polygon layer with every cities in my region. One of the field of this layer is the population of the city. I also have a line layer which represents some bus route I would like to ...
0
votes
1answer
38 views

How to get osm tiles in QGIS 3

I am completely lost in the dozen of solution I've found. I would like an easy solution to create an OSM basemap for my different projects with nice styling. I work directly on my computer, no ...
1
vote
1answer
21 views

PyQGIS - Add items to print layout

I have created a blank print layout, now I want to add items to it like a map, legend, etc. Here is my code so far to create a new print layout, this works just fine: #This creates a new print ...
2
votes
0answers
31 views

Does the Clipper plugin for QGIS work for Shapefile layers?

I created 2 overlapped polygons in one Shapefile layer, run the intersection tool with another layer and then run the Clipper plugin. This causes the error: TypeError: MultiPolygon geometry cannot be ...
0
votes
0answers
12 views

QGIS 3.4 - Access Violation no RTTI data

i'm used to writing in C for embedded systems, so python is somewhat new to me. I've built up this script in QGIS script editor following the template. However, when I run the script I get an Access ...
2
votes
1answer
28 views

QGIS general character encoding

This isn't a particularly major issue, but I've had this thing nagging me for a while. When looking at QGIS 3.4's global variables, user_full_name is assigned my given and surname, which includes a ...
0
votes
0answers
9 views

How to increase the header height for an Layout Attribute Table in QGIS 3?

I need to increase the header height because the header text has 2 lines. The only way I could find to increase it was use cell margins. But that affects all rows. How to increase the height of the ...
1
vote
0answers
37 views

Strange behaviour viewing world map with EPSG:4326

I'm trying to visualise/convert EPSG:3857 map tiles to EPSG:4326, but am experiencing strange behavior in that I don't think the most zoomed out view of the world is using the correct CRS/Auth ID. ...
1
vote
0answers
12 views

QGIS 3.4.3 touch zoom and pan

QGIS 3.4.3 touch zoom and pan missing from Map Navigation Toolbar is this a permanent loss or will there be a fix?
4
votes
1answer
114 views

RGB TIFF goes black when zoomed out in QGIS 3.4!

Am importing a RGB TIFF into QGIS 3.4 and when I zoom in I can see the image properly, however, when I zoom out the layer turns black (most of it) and red (a small portion). After doing some search I ...
1
vote
1answer
40 views

Method asPoint().x() doesn't work in QGIS 3.4.3 but did in 3.4.1

I have built a plugin which does essentially this equal sized polygons along line Main parts of the code are from user lejedi76 I have used this plugin for months now and it worked as expected. ...
0
votes
0answers
25 views

QGIS plugin - Works on PC, not on Mac

I'm adding some functionality to an existing QGIS plugin (EcoValuator from Key-Log Economics). After playing with the existing version of the plugin, it works on a PC, but not on a Mac. The issue is ...
1
vote
0answers
13 views

Using formatting option 'aligned' in 'to_dms' function in QGIS 3.4.2

Using formatting option 'aligned' in the expression: to_dms(x(transform($geometry,'EPSG:32632','EPSG:4230')), 'x', 2, 'aligned') not only is the alignment of degrees, minutes, seconds as expected, ...
0
votes
2answers
39 views

Applying SVG marker as additional symbol to polygon layer in QGIS 3

I would like to add SVG markers as an additional symbol to a polygon layer. The polygon layer is rendered with a categorized symbol renderer with different fill-color, and I want to add SVG markers ...
3
votes
1answer
23 views

MMQGIS Geocode is failing in QGIS 3

I am facing troubles geocoding the CSV file in QGIS 3 with MMQGIS (OpenStreetMap). Images below are showing my workflow and the problem that I am encountering. I am getting the following error: ...
1
vote
0answers
23 views

Opening template project with PyQGIS in QGIS 3?

What do I need to do to open a project-file as a template with PyQGIS in QGIS 3? I am able to open a project like this: project = QgsProject.instance() project.read('C:/path/to/my/project.qgs') But ...
3
votes
1answer
74 views

Install QGIS plugin manually - Package not available in Plugin Manager

If it is helpful, I am using QGIS 3.4.3 (Madeira) and MacOS High Sierra v10.13.6 I am trying to install a QGIS plugin manually, I've been using the instructions from the PyQGIS Programmer's Guide by ...
1
vote
1answer
32 views

Writing pyQGIS 3 script to modify layer (add field and feel it) inside QGIS?

I have the following PyQGIS script with QGIS 3 that tries to ask for a layer, add a new field in that layer and modify the value of this field. But the code doesn't work. I get either Seems there is ...
2
votes
0answers
23 views

Showing split polygons in different layers in QGIS

I used the split feature to split a polygon into two parts. Is it possible to show the split parts in sub-layers in the layers panel, so that I can hide them individually? I am using QGIS 3.
2
votes
1answer
95 views

QProgressDialog in QGIS 3.0 not updating

I am using a QProgressDialog to show the progress of a routine that is running. I found this very helpful question/answer how-to-show-a-moving-progress-bar-in-qgis, but I can not reproduce successful ...
1
vote
1answer
28 views

Inputting CSV in QGIS graphical modeler and defining its geometry [duplicate]

Is it possible to have a model in QGIS graphical modeller which accepts a CSV with geometry fields and then allows you to use them for the rest of the model as if it was a vector file? This is ...
0
votes
0answers
36 views

Looping through Clip Raster By Mask function

I created a script to loop through the Clip Raster By Mask function. I assign my personal files to the variables and use a nested for loop to iterate through the feature ID numbers in my selected ...
1
vote
1answer
41 views

Is there any plugin that plots a profile from point survey data in QGIS 3

I used to work with the plugin ProfileFromPoints, but it is not avaible 8or updated) in Qgis 3. I wonder if there is another one which does the same or if there is an easy (foolproof) way to use the ...
0
votes
0answers
33 views

QGIS 3 - Variables in rule-based rendering?

I'll try and lay this out clearly, I have most of it covered, but there's a very specific thing I'm looking for in the rules - whether or not it can be done and if so, how? Key things I have done and/...
1
vote
1answer
42 views

Export MultiPolygon data as WKT from QGIS 3

I have the polygon data for the city of Kamloops in QGIS 3. When I try to copy features of this polygon and try to paste it over here: https://arthur-e.github.io/Wicket/sandbox-gmaps3.html I don't get ...
2
votes
1answer
38 views

Method to convert all 'overlapping' points to exact same geometry in QGIS 3.4

I have a point vector layer with approximately 2.5 million points, many of which share the same or a very similar geometry (within 1 m of each other). I would like to know if I can bulk amend the ...
0
votes
1answer
32 views

PosGIS KNN returns different results from QGIS hub spoke function

Following example here I have tried to get nearest neighbours where code is; CREATE TABLE model.hub_spoke_spokes3f AS SELECT hub.id AS hub_id, spoke.id, spoke.point_geom, ST_Distance(hub....
1
vote
1answer
47 views

Efficient way to find polygons with no neighbours, eg, detached houses

I have a map of buildings, I'm looking to identify only those buildings which are detached (no neighbours). I can run select by location touches in QGIS and invert this but it does not seem the most ...
4
votes
2answers
130 views

QGIS Joined Layer not displaying points visible on pre-join layer (No Extent)

I have a shp file which is the output of the Toolbox Check validity tool in QGIS 3.4.3 The points display for me correctly but if I then join the layer with a csv attribute using the toolbox Join ...
1
vote
0answers
34 views

Printing plugin data on QGIS map canvas

I created a Python plugin in QGIS & when i am running my plugin it printing the data on python console. But i want that when i run my plugin it will print the data on QGIS map canvas. How can i do ...
0
votes
2answers
47 views

Faster alternative to `Intersection` in QGIS to just retain overlapping features without cutting

I want to keep only the features from my data layer (polygon A) within my area of interest (AOI). If I compare two methods to perform that, the processing time is very different. Intersection tool I ...
3
votes
0answers
41 views

Updating Algorithm list in pyqgis3?

I am attempting to run a union operation in a standalone pyqgis script and I'm receiving this error: Algorithm qgis:union not found The union operation fails with this code: params = { 'INPUT' ...
2
votes
0answers
27 views

How to create a valid QgsVectorLayer from a PostgreSQL view?

I am attempting to create a QgsVectorLayer with the same code as I am using for a PostgreSQL table, which works correctly and the isValid() method on the layer returns true. uri=QgsDataSourceUri() ...
1
vote
1answer
49 views

How to Create Gradient map from GRID file in QGIS-3 Above?

I have a very important Question. I have a GRD file which can be opened in SURFER or QGIS or GIS. The problem is that how can I customize and make my grid file perfect? Here I have two photos which ...
0
votes
1answer
18 views

Can a Geopackage style be deleted through SQL window in DB Manager?

I am trying to clean up a Geopackage and as part of this I would like to delete some styles from the "layer_styles" table. I have tried doing this with the below query in the SQL window of the DB ...
1
vote
0answers
14 views

Match a custom CRS to existing (proj4 database) ones in QGIS 3

I am reading SPS files (see format definition here) from which I gather CRS information. Unfortunately, there is no ESPG reference available nor is there any standard naming scheme for Ellipsoids so ...
2
votes
1answer
54 views

How to open and add SQLite connection to browser with PyQgis

I have a code to open the layers of a SQLite database. When executing this code, the layers are loaded correctly (1 & 2). However i also need to connect to the database and show the connection in ...
0
votes
0answers
32 views

How to edit manually file geodatabase's OBJECTID column in QGIS?

I'm using QGIS version 3.4.1 with a Windows 10 OS. I'm trying to edit an Esri FGDB folder. Haven't succeeded. So far so I'm using a workaround: exporting specific layer to a new FGDB - with 'Save ...
0
votes
1answer
20 views

Why can't I load layers from PostGIS db (populated with osm2pgsql) in QGIS?

I have downloaded some OSM data from geofabrik and used this to create a PostgreSQL/PostGIS database using the osm2pgsql tool: osm2pgsql -G -d <db> -U postgres myfile.osm Examining the ...
0
votes
0answers
42 views

QGIS 3 Plugin with cascade list runs slower each time I launch it

I'm writing write a plugin for QGIS. Its first step is to select an item after having selected 'parents items', in a cascade selection. It works, but it is getting slower and slower after a few ...
1
vote
0answers
29 views

In QGIS, How to add the database connection in DB Manager via Python [closed]

I am using QGIS 3.0.2 I want to add connection settings in DB Manager via Python script. is it possible ? (I am interested in PostGIS and Oracle Spatial for now) This script will save the ...
0
votes
0answers
34 views

Display issues in QGIS Madeira

This is the second time I have tried installing Madeira on a new Dell XPS machine (Madeira works okay on my old Mac although there are some bugs including with changing font sizes in a layout). This ...
1
vote
1answer
41 views

QGIS 3.4.3 Refactor fields changes symbols in fields (cp1250)

I've been using QGIS Refactor fields to change type, re-order and rename a substantial ammount of columns (statistical data). Most of them hold purely numerical values and are as such not material to ...
2
votes
0answers
68 views

Unresponsive MessageBar in QGIS 3

I created a little plugin to geocode addresses using the HERE API and QGIS 3. Especially in batch mode, I can see that the plugin is iterating over my features in a table and my messageBar progress ...
0
votes
1answer
28 views

Difficulties working with QGIS 3.4 API

I want to work with QGIS 3.4 in a C++ Qt project, but the API in version 3 has been completely changed and the sample code for older version don't compile anymore. Is there some sample code which ...
1
vote
0answers
36 views

How do you view your Python scripts in the processing toolbox in QGIS 3?

I have been stuck on this for a while and I'm not sure if it is a bug or me doing something wrong but I cannot work out how to add Scripts to the processing toolbox in QGIS 3 series. When I click the ...
1
vote
0answers
21 views

Way of viewing attribute table of layer at end of model without loading layer in QGIS

I have created a model in QGIS 3 graphical modeler, with the final output being a shapefile. I was wondering if it is possible to have the final result as a pop up of the data table just to view the ...