56
votes
Accepted
Filtering features in other layers of QGIS Atlas
Indeed, you need to use rule-based symbology to achieve what you want.
You need to create a rule for what you want to show, and ELSE rule for all others.
In the ELSE rule, deselect the symbol ...
- 14k
45
votes
Change style properties of several layers simultaneously?
This works for QGIS 3.4 =>
Create a group of all the layers you want to have the same style
Edit the style of one of the layers in the group to your liking
Right-click the correctly styled layer; '...
- 686
31
votes
Accepted
What are the min and max values of Map.addLayer on Google Earth Engine?
Let's start from the beginning.
How satellite remote sensing work
Satellites carry out sensors that can measure radiance at different wavelengths (it depends on the sensor)
For example,
Landsat ...
- 9,890
27
votes
Getting list of layer names using PyQGIS
Since version 3, QgsMapLayerRegistry funcionalities have been moved to QgsProject: https://qgis.org/api/api_break.html
Update for QGIS3.x:
from qgis.core import QgsProject
names = [layer.name() for ...
- 6,364
25
votes
Iterating over map layers using PyQGIS
For QGIS 3, QgsMapLayerRegistry's functionality has been moved to QgsProject.
So, for iterating over map layers, you should use that structure:
layers = QgsProject.instance().mapLayers()
....
- 74.7k
25
votes
Accepted
Getting field names of layer using PyQGIS
To get field names with fields() method or other field properties (length, type, comment, ...) you can use:
field_names = [field.name() for field in layer.fields()]
# ['id', 'attr1', 'attr2', 'attr3']
...
- 74.7k
24
votes
Accepted
Setting layer transparency in QGIS 3
You have to click on the layer rendering arrow (see the bottom of your second image) to access the slider and other option.
in QGIS 2 it was on by default, in QGIS 3 it's off by default...
- 14.5k
22
votes
Duplicating layer in memory using PyQGIS
In QGIS 3 you can make a copy of a layer without saving any reference to the parent layer in this way:
layer.selectAll()
clone_layer = processing.run("native:saveselectedfeatures", {'INPUT': ...
- 1,343
22
votes
Accepted
Making layer or group private/hidden/invisible in Layers Panel of QGIS
Just to clarify, private/hidden layers/groups will not appear in the Layers Panel, but they can still be seen in the canvas or used in joins/relations with other layers.
Native approach (QGIS API)
You ...
- 35.8k
21
votes
Setting layer transparency in QGIS 3
As an alternative option, you can open Legend tab and select Opacity slider widget.
It will add an opacity slider in the Layers panel.
- 30.4k
21
votes
Accepted
Showing the number of currently selected layers in QGIS
You can use this script. It adds a toolbar as seen in the image and shows how many layers are selected.
label = QLabel("Selected Layers Count:")
count = QLabel()
tree_view = iface....
- 74.7k
20
votes
Accepted
Duplicating layer in memory using PyQGIS
The following code works for me from both the Python Console and plugin. It takes the features from the source input layer and copies the attributes to a memory layer (in this case, a polygon layer ...
- 75k
19
votes
Accepted
Activating layer by its name in PyQGIS
TL;DR
To get all features of a layer by the layer name you do not need to activate it. Just use
name = 'counties'
layer = QgsProject.instance().mapLayersByName( name )[0]
poles = layer.getFeatures()
...
- 27.5k
19
votes
Understanding Coordinate Reference System of QGIS Project and Layer
Short answer: there is project CRS and layer CRS:
You can more or less freely choose any project CRS, QGIS handles the rest automatically.
You can't "set" another CRS for your layer (your ...
- 63.1k
18
votes
Using layer loadstart & loadend events in OpenLayers 3?
In ol3 version 3.10.0 things have changed. So is more clear than older versions but still more complicated than ol2.
So for TILE (ol.layer.Tile) layers your code snip should look like:
//declare the ...
- 3,538
18
votes
Accepted
Check if layer exists in QGIS Project using PyQGIS
len(QgsMapLayerRegistry.instance().mapLayersByName('the_Map_Layer_in_question')) != 0
Trueif layer exists, otherwise False
- 4,538
17
votes
Accepted
Symbols above labels in map QGIS
I don't think there is a way to do this in the map canvas itself. The labels will always be on top at least in QGIS 2.x.
But for the print composer, you can work with two maps. They should be in the ...
- 16.3k
16
votes
Accepted
Reprojecting layer using PyQGIS
You can use processing algorithm native:reprojectlayer.
Example:
lyr = iface.activeLayer()
parameter = {
'INPUT': lyr,
'TARGET_CRS': 'EPSG:4326',
'OUTPUT': 'memory:Reprojected'
}
result = ...
- 7,780
16
votes
Accepted
Change vector layer symbology PyQGIS 3?
The easiest for me would be to check the properties of the symbology layer which contains symbol properties affecting the whole layer:
dir(symbol)
>>>['DynamicRotation', 'Fill', 'Hybrid', '...
- 75k
15
votes
Accepted
Adding Properties to a feature in Google Earth Engine
Yes, you can use the feature.set()option which Feature Overview covers with these examples:
// Make a feature and set some properties.
var feature = ee.Feature(ee.Geometry.Point([-122.22599, 37.17605]...
- 12k
15
votes
Getting field names of layer using PyQGIS
List field names with dataProvider() method
from qgis.utils import iface
# get active layer if not already set
layer = iface.activeLayer()
prov = layer.dataProvider()
field_names = [field.name() ...
- 1,003
15
votes
Turning on/off ALL selected layers in QGIS
In the Layer pannel, there is an icon in form of an eye : Manage Map Themes (documentation) :
By clicking on it, you can see the option for display / mask the selected layers.
You can also go to the ...
- 15.5k
15
votes
Showing the number of currently selected layers in QGIS
To extend the great solution by @Kadir Şahbaz, you could do something like this to get a count per group:
p = QgsProject.instance()
root = p.layerTreeRoot()
view = iface.layerTreeView()
## TOOLBAR
tb ...
- 14.2k
14
votes
Merging multiple vector layers to one layer using QGIS
In the meantime, a tool called "Merge vector layers" has been added to QGIS under Vector > Data Management Tools > Merge Vector Layers or under Vector general in the Processing Toolbox ...
- 283
14
votes
Setting layer visibility in QGIS Python API?
For QGIS 3, you have to use:
QgsProject.instance().layerTreeRoot().findLayer(layer_id).setItemVisibilityChecked(False)
or to be safe
node = QgsProject.instance().layerTreeRoot().findLayer(layer_id)...
- 1,451
14
votes
Accepted
Is it possible to set different scale dependent visibility for one layer classifications?
You need to use Rule based style to set the scale for primary, secondary and tertiary network, as you can see below (but with different data):
You can double-click each styled label to get more ...
- 40.3k
14
votes
Accepted
Editing shp layers style simultaneously in QGIS?
With a little help from Python, we could set the border width for all layers in your "State" group to a specific value (e.g. 0.16 as shown in your image).
Try testing the following in the Python ...
- 75k
14
votes
Accepted
Create Layer from Selected Features tool: How is the list of features stored?
Create Layer From Selected Features DOES NOT create a DYNAMIC layer. The resulting layer is not dynamic at all. It is based on an FIDset.
If you change the source data, the FIDs will change and your ...
- 7,275
14
votes
Accepted
Selecting layers in group using PyQGIS
You can use the following lines:
newtable = QgsVectorLayer("None", "Results", "memory")
provider = newtable.dataProvider()
provider.addAttributes([QgsField('Layername', ...
- 74.7k
13
votes
Georeferencing vector layer with control points using QGIS?
I recommend the Vector Bender plugin for QGIS.
I tried it and it works fine and is user friendly.
Depending on amount of pair of points that you define, you can either do:
translations: translation ...
- 1,152
Only top scored, non community-wiki answers of a minimum length are eligible