Questions tagged [mapcanvas]

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7
votes
1answer
133 views

QGIS: Is there a way to make the “Python Console” a separate window?

QGIS 3.10; Ubuntu 18.04 When Plugins->PythonConsole is accessed, it opens as a panel, changing the shape of the map canvas. Can it be a separate window instead? Alternatively, is there a way to run ...
1
vote
0answers
17 views

How can i save and load items in canvas format in leaflet?

I've created a leaflet map and added draw control. I can draw lines, polygons, and markers but I need to add a canvas and draw my favorite drawing items like this : I want to save these items and ...
3
votes
0answers
10k views

Hiding a layer in Layers panel, but showing in Map Canvas

When a layer is added to QGIS, it is ordinarily added to "Layers" panel and "Map Canvas". The same thing happens when a memory layer (loaded/created by QgsVectorLayer) is added using QgsProject....
2
votes
1answer
31 views

Shortcut to activate and deactivate a layer filter

I'm looking for the fastest way to filter and unfilter a layer in qgis 3. My current workflow is too tedious: right click on layer / filter / write filter or delete filter My final goal is to see ...
0
votes
1answer
93 views

Adding layer to canvas crashes QGIS

I am having some difficulties in adding a layer to my canvas or even to main project. I create a plugin in QGIS 3.10. This plugin has a table of contents and a canvas to open some maps. I search and ...
1
vote
0answers
37 views

2D canvas library for OpenLayers. Drawing custom interactive objects

I am looking for the 2D canvas library like Konva.js that I can use above OpenLayers 5.x. I need to draw shapes with font inside that are interactive - can be dragged over the map to the appropriate ...
1
vote
0answers
267 views

PyQGIS (3.6.3 Noosa) Why is self.iface.mapCanvas().setExtent() being overridden in plugin?

I am writing a plugin that first adds the Google Imagery XYZ tile layer and then adds various other layers - some from a GeoPackage and others by creating their geometry in PyQGIS. The last function ...
1
vote
0answers
2k views

Increasing size/height of OpenLayers map/canvas?

I'm trying to let the Map/Canvas height of OpenLayers 100%, but I'm not able to do it. I've already tried putting in several places the "height: 100%;" and used the "map.updateSize()" function, but ...
2
votes
1answer
67 views

Unable to delete certain elements from my map

Can anyone help me get rid of these 2 boxes ? I can't figure out how they showed up in the first place... I've remove the check marks next to all my layers and the boxes won't go away. I'm getting ...
1
vote
1answer
658 views

Get QgsLayoutItemMap from existing QPT Layout

I created a QPT model with a map inside QGIS. The problem is when I try to select the map under pyQGIS : qpt = QDomDocument() qpt.setContent(content) layout = QgsLayout(QgsProject().instance()) ...
2
votes
0answers
452 views

Add OpenLayers map on map canvas with PyQGIS

I have map canvas with two shapesfiles, and I want to add OSM map behind. My code for this is: from PyQt5.QtGui import * from PyQt5.QtWidgets import QHBoxLayout, QDockWidget, QWidget from osgeo ...
0
votes
1answer
225 views

How to set 2 vector layers into map canvas, pyqgis 3.0

I have 2 shapefiles which I need to lap. The first one is city grid, and the second one representing borders of the city. Anyway, my code is: extent = QgsRectangle() layers = [] QgsProject.instance()...
1
vote
2answers
668 views

Export Map Error from OpenLayers 3 in Chrome?

Im using this js file to export map in Openlayers 3 in Google Chrome but i'm getting en error saying that Uncaught DOMException: Failed to execute 'toDataURL' on 'HTMLCanvasElement': Tainted canvases ...
2
votes
1answer
871 views

Use a second canvas for drawing an animation in Openlayers

I want to implement an animation of flowing rivers on top of an Openlayers map. My doubts are if I simply should make a new canvas and position it on top of the map or if there is a more elegant way ...
12
votes
2answers
473 views

Displaying generated lines out of map extent using QGIS?

I have drawn an OD flow map using QGIS geometry generator, using the following expression : make_line( centroid( $geometry ), centroid( geometry( get_feature( 'Layer2', 'Attribute1', attribute( ...
1
vote
0answers
352 views

Implementing 'Add feature' functionality programmatically to QGIS?

I have a script that is adapted from the book Menke - Mastering QGIS and used to draw a polygon directly on the map canvas. Now I want to expand upon that script and mirror the 'add feature' ...
8
votes
1answer
264 views

Accessing QGIS map canvas as a variable for expressions

Is it possible to access the QGIS Map Canvas as a variable or expression value to be used in the field calculator or labelling engine? (i.e. so that you can create an expression that selects/...
2
votes
0answers
340 views

Label only one polygon in canvas/map view per category/value in attribute table

Question: In QGIS (2.18), how do you show only one label per field of view in the map canvas for each visible category (that is displayed in the map view/canvas at any given scale/focus) of a multi-...
4
votes
1answer
296 views

Recursive loop to modify vector layer and refresh mapcanvas

I'm trying to plot one point "jumping" each second in the canvas (like a gps tracking). I need to take points from a .csv file. This functionality is made in a QWidget of my application, so the code ...
5
votes
1answer
1k views

How to set QGIS map canvas size programmatically

I need my map canvas to be exactly 1920x1080. So the Save as image would save a png exactly this size. I've tried setting it with iface.mapCanvas.resize(QSize(1920,1080)) But no luck, resize() ...
2
votes
1answer
703 views

How to determine when the map has finished rendering

I have written a few functions to compare QGIS performance to MapInfo. Most of them involve doing some analysis then dumping the results on the map, as such the process would be considered 'finished' ...
2
votes
1answer
1k views

Dynamically move map canvas and main window using PyQGIS

I am trying to create plugin that will open new window with some layer, Dynamically "pan" my window, when main window is pan. So boundingbox coordinates should be the same in both windows. I need new ...
5
votes
1answer
2k views

How to get attribute values from vector features visible in the qgis canvas

I have a vector layer (grid). Currently I select some tiles with the select tool and paste some python code to get information about these features. layer = qgis.utils.iface.activeLayer() ...
1
vote
0answers
137 views

Qgis python: no interaction with Map Canvas

I've created a simple python script to load and show two layers and zoom to the first one. It looks like the script doesn't run the last 4 lines after I uncomment'print lyr1'. Anyway the map canvas is ...
5
votes
3answers
5k views

Refreshing MapCanvas while PyQGIS-script is running

I try to write a PyQGIS script similar to this: Use of python console to prepare offline map from WMS (tile downloader). Basically there are two loops to pan the mapCanvas, refresh the mapCanvas and ...
4
votes
1answer
946 views

How can I optimize layer filtering using setSubsetString or QgsFeatureRequest().setFilterFids(my_indexes)

i'm developping a plugin (under QGis 2.8.1) for traffic assignment where I want to show the results of my simulation at each time step. Right now I'm using Time Manager plugin but it gets very slow ...
1
vote
0answers
86 views

Mapcanvas not showing layers features

usually when i load an osm file with lots of features (>10000) the qgis will go not responding, when the files loaded, layers will show up, but not the features on the map canvas, its just blank ...
2
votes
1answer
672 views

zooming map in QGIS map canvas without changing the scale

I use QGIS to create maps mainly for printing in scale 1:100.000 to 1:25.000. It would be great, if the map in the canvas could be zoomed without changing the scale of the canvas. The only way to get "...
1
vote
1answer
702 views

Add a canvas on the map that can pan and zoom along with it

I want to know if it's possible to add a canvas on a ArcGIS map that can pan and zoom along with it. The reason I ask that it's because we have different workflows where we have a lot of entities (+...
2
votes
1answer
52 views

the renderering of mapcanvas is still active

i am working with qgis c++ api 2.8.2 and qt4.8.5 i want to disable the rendering during zoom in or zoom out fonction in order to have a fast zoom i try to use : MyMapCanvas->stopRendering(); and ...
4
votes
1answer
1k views

Drawing polygon in QGIS map canvas

I want to make a custom application which includes an option just like the "Select Features by Polygon" feature in the QGIS. I am able to draw the polygon using following code: self.rb = ...
2
votes
0answers
302 views

Map canvas saveAsImage() method saves wrong image in QGIS

I've been trying to write a small python script to output 2 tif's based on given box extents. The script all works, box coordinates convert to project coordinates, zooms to right place (would like ...
1
vote
1answer
839 views

OpenLayers 3 WMS layer to canvas

I am taking the context and taking it to a canvas which was asked here and the answer can be found in this JSfiddle example. However, I am looking to load a WMS layer from geoserver and extract only ...
1
vote
1answer
564 views

How to re-render only a single layer on a mapcanvas?

In my application I have a mapcanvas that contains several layers. some of layers need to be updated or rendered again because data has been changed ( like the geometry or some attributes ) Is there ...
0
votes
1answer
206 views

How can i catch clicked signal on a qgsmapcanvas

I am working under c++ with the qgis API 2.8 In order to make different operation on a canvas like personnalized rotation or selecting a region for zooming, I had to catch different signal like ...
2
votes
0answers
562 views

PyQGIS Set Extent for loaded layers - Refresh problem

I've written a plugin which loads a number of map layers (based on constraints) and I would then like to set the canvas extent to a selection of them. Code very similar to that below works perfectly, ...
1
vote
0answers
137 views

How to set QGIS mapCanvas to exact values

My QGIS 2.8.2 standalone app's mapCanvas fills a central widget with a fixed quadratic size x=y=1000 pixels. When I set the mapCanvas extent() to an area defined quadratic as well given by a ...