Questions tagged [vector-layer]

A vector layer represents geographic data whose features are given by sequences of points. (Contrast with a raster, which is a grid of values.)

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1answer
43 views

Automatic filling of rings with additional polygons in QGIS

I have a large layer with a couple of thousand polygons mapping inland waterbodies. A lot of these contain rings, mapping islands. I would like to count the number of islands and do some statistics ...
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24 views

How to dissolve a subset of a multipolygon vector in QGIS?

I have a multipolygon layer. Some of the polygons within the layer overlap. I would like to dissolve only the polygons which overlap and not any discrete polygons. Is this possible? I am currently ...
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1answer
35 views

QGIS Natural Earth Geometries

When I insert country borders from Natural Earth, they look broken when zoomed out. When I zoom in they look correct. Is there any way to correct this, particularly when creating a map in layout?
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31 views

Can't add vertex to polygon in QGIS3

I'm working in QGIS3.8.3 and am trying to use the Vertex Tool to add a vertex to a pre-existing polygon. I expect to be able to do this in an editing session by hovering over the segment in question ...
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2answers
58 views

WFS point layer does not appear on OpenLayers map when called from GeoServer

I'm writing because I attempted almost all the tries suggested in any other Q/A on this thread. I have this vector points layer on my local GeoServer and i'm trying to plot my points on a OSM base map ...
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0answers
34 views

Measuring area of raster within polygons using QGIS

I am trying to use QGIS3.10 to analyze the area of forest within regions. It looks like this where the polygons belongs to WFS layer and Rasters belongs to WMS layer. The legends fo Raster suggests ...
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0answers
18 views

Which type of slash to use in path - QGIS 3.8 with Python [closed]

I'm a beginner using Python. I had a problem loading a shapefile in QGIS 3.8 using Python, while loading a rasterfile worked perfectly. I found the solution here: Can't load a shapefile with ...
3
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1answer
50 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....
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Approximation of data in ArcGIS

I have a problem in the section graduate( symbology--->graduate). I want to scaling data from 0 to 0.9 in ten step, but when i put in the cases a range from 0.0 to 0.1 (or 0.1 to 0.2 etc) the system ...
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1answer
37 views

Split vector by field name and rename output files according to field value

I have a shapefile with several features and want to split the layer into separate shapefiles. I looked into similar questions recommending Split Vector Layer. However, I could not find a way to ...
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2answers
95 views

Get field names in attribute table with Python

I have a geopackage file, with a layer called "MyLayer". Within this I have an attribute table with approx 20 attributes. I can read in each attribute individually like: import geopandas as gpd ...
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1answer
38 views

Add GeoJSON features from an API call in OpenLayers 4, layer not displayed

I'm trying to create a little demo to show the data from our API into a map but I cannot see my layer Here my code, is just basic for the moment, we just need to display the data: const projection = ...
3
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1answer
192 views

Difference between two vector layer

I have two vector layer land cover for 2016 and 2018. I want to get result layer that will show changes in land cover e.g. the forest has changed into a meadow. What option in QGIS can I do that. In ...
2
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1answer
49 views

OpenLayers-v5: How to get WFS features before vector layer is visible

I expected a WFS call to be made when a Vector Layer was added to the map, but it doesn't happen until the layer is marked as visible. Here is how I'm currently creating my vector layers. The visible ...
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0answers
23 views

Changing features attributes in OpenLayers

I am using OpenLayers 5.3.3 and I want to change attributes of the specific feature in my map in OpenLayers. After changing the features I want to the changes to be updated in my map. this....
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0answers
28 views

Icons/Features disappear after removing one feature from vector Source

I am using OpenLayers 5 and i have a map which has multiple icons. When i try to remove an icon from my map, all the icons disappear at once. Code Below is to add the vector source which contains ...
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1answer
47 views

OpenLayers: projection of WMS and vector layers

I have two layers in my OpenLayers map, the background in WMS and GeoJSON features in a vector layer, both in ESPG:3006. (And a standard OpenStreetMap background just to see which one of the layers ...
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0answers
77 views

Use svg file in openlayer to represent a layer

I want to use an SVG file as a source for one of the layers for my map in OpenLayers. The svg file is in a coordinate system such that it overlays my coordinate system of my map. I have tried the code ...
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2answers
57 views

Realising vector file mapping using QGIS Modeler?

I pretty often get lots of vector files with different column namings. I need to produce a defined vector data file with certain columns. Is it possible to build a model that allows to make a mapping? ...
2
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1answer
70 views

Pyqgis Set the field value of a dynamically created vector layer in QGIS 3 before user saves to database

I am quite new to both QGIS and Python. I have inherited a project that needs to be upgraded from using QGIS 2.0 DUFOUR to 3.8 Zanzibar. The way it works is, there is a separate application written ...
4
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3answers
78 views

Counting number of polygons inside zone using QGIS?

I've seen a lot of questions about counting the number of points within a polygon but my question is I have 1 vector layer with polygons showing past landslides that have occurred and another 206 ...
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1answer
41 views

'Unknown exception' when editing vector layers in QGIS [closed]

I keep coming across the unknown exception error message when trying to edit or add to a vector layer. Anyone else come across this problem? Any fixes? I'm currently running QGIS 3.4
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0answers
23 views

Error when using v.net in GRASS GIS

I'm new to using GRASS GIS and GIS in general. I have a point layer and a line layer which I added on to the layer tree using two .shp files. I need to use v.net tool to create a network by connecting ...
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1answer
68 views

Error Updating the Attributes value [closed]

The code below is not working: This code doesn't affect the table at all layer = point_layer3 selected_feature = layer.selectedFeatures() print(len(selected_feature)) layer.startEditing() for ...
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0answers
29 views

Labelling only the selected features with custom text using pyqgis

I want some alternate to this code as this code just labels only the current feature in the loop . FEATURES = point_layer3.selectedFeatures() for f in FEATURES: total = f['parkeer_approx'...
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0answers
70 views

Changing color of each selected feature based on expression using PyQGIS?

Code below changes the color of all the selected features based on the last condition it satisfied instead of changing the color of the feature which satisfied the condition. for f in FEATURES: ...
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2answers
102 views

How to transfer POI layer from QGIS to OSMAnd?

I've got a POI layer (vector layer with single-point geometry) in QGIS and would like to import these points to OSMAnd under "My Locations" including the attributes (like name of the point). How can I ...
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1answer
69 views

Style OpenLayers.Feature.Vector in OpenLayers.Strategy.Cluster()

I'm using the clastering feature in my project. I collect list of points like so: cluster_features.push(new OpenLayers.Feature.Vector( new OpenLayers.Geometry.Point(lon,lat), {heading:deg} )...
2
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1answer
199 views

Access geometry.coordinates of sliced vector grid

I am trying to represent LineString GeoJSON as vector tile layer using Leaflet.VectorGrid. But i need to do some interactive by clicking on vector tile layer. but this vector tile layer has came with ...
2
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1answer
102 views

Delete points inside a polygon

I am working under QGis 3.4.8 Madeira under Windows 10. I have uploaded two layers on my project. Layer A is a points layer. Layer B is a polygons layer. Some points of layer A are located in the ...
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0answers
42 views

CRS Options Missing

I'm very new to GIS and am trying to use QGIS 3.4.8 to map some spatial data for a larger project. I've been using OpenStreetMap as my basemap, managed to load in my vector layers and for a few days I ...
2
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1answer
69 views

Identifying overlapping lines within layer

I am trying to identify the overlapping lines within a layer that consists of polygons of land parcels. I have already converted my data to lines and exploded those lines. Indeed, I have run a "no ...
3
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2answers
61 views

Symbology for traffic direction into and out of city

I'm using QGIS 3.4.7. I have one vector layer with road lines and a second with city polygons (and a third with city centroid points if that is better). I have already used symbologies with arrows to ...
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1answer
211 views

Use PNG external graphic for vector layer with OpenLayers 5.3

I am currently working on a webmapping project using Mviewer device, linked to OpenLayers 5.3. I am trying to create a new vector layer to locate points, with js. So far, I managed to create a layer ...
0
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1answer
257 views

OpenLayers refresh vector source with bbox strategy after map moved

I have a vector layer, in GeoJSON with a Vector source on which I applied the BBOX strategy. I have unique IDs for each feature in the layer and having a look at the network tab in the browser the ...
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2answers
223 views

Networks plugin missing from QGIS 3.4.7?

I installed the Networks plugin in QGIS 3.4.7 successfully, but it does not appear in the Vector Tab. Can anyone suggest another way to reverse the direction of a vector used in a network (graph)?
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1answer
516 views

Changing Opacity of Vector layer in Google Earth Engine

While importing a Shp file in Earth Engine, I want to control or change opacity/transparency of the layer. I have gone through almost all read me files, I find nothing. This doesn't work: Map....
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1answer
84 views

Summing amount of vector points in area of another vector using Google Earth Engine?

So I have 2 layers each are both vectors and not images. here the link: https://code.earthengine.google.com/e7aec6c9683ed40a959a01a7ed5dd31f I have written some basic code to display the data which ...
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0answers
18 views

mssql Vectorlayer import have no Coordinatesystem

Hi I'am using QGIS Version 3.4.6. If I add a Vectorlayer out of my mssql database a CRS dialog pops up for choosing a coordinatesystem. Like loading layer without CRS. uri = QgsDataSourceUri() uri....
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0answers
86 views

PyQGIS overlaying raster image on vector map correctly?

I have some code written in Python using PyQGIS where I am trying to overlay a raster image gridded with coordinates on to a vector shapefile map with the same coordinates. However, when overlaying ...
3
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3answers
754 views

Assign a specific color to vector layer based on RGB codes in attribute table

I use QGIS and have a geological map for a large area. I present this after ID codes based on the geology ("Geokartnr" in photo). I want to use international/nation color codes for each rock type, ...
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0answers
46 views

Identify same entities across time period

I have a few election district boundaries layers across several different elections, and I am trying to ascertain whether/how much the district boundaries have changed over time. They are labeled ...
4
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2answers
176 views

Is a PK required for GeoPackage vector layers?

According to geopackage.org's "Getting Started With GeoPackage" guide, features are stored in user-defined data tables. It seems like it says that these tables require a primary key: Other than the ...
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1answer
53 views

How to set layer transparency QGIS C++ API 2.14?

I want to set transparency for already loaded layer by taking it from canvas QgsVectorLayer *myLayer = mpMapcanvas.layer(0); myLayer.setLayerTransparency(50); myLayer.triggerRepaint(); but get an ...
2
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0answers
91 views

Inverting shapefile in QGIS 2.18?

I asked a question earlier about how to invert my file "hydropolys.shp" from a vector of ocean and seas to a vector of land and got sent to here, but I am experiencing issues where using the "...
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0answers
28 views

How to make the background of an shapefile the vector layer? [duplicate]

So from another question I asked about show raster layer over background, I learned how to duplicate a shapefile and use the inverted polygons tool to make the land the vector layer. I am now ...
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0answers
159 views

automatically georeference QgsGeometry.fromPoint features on creation

Is there a way to automatically georeference fromPoint features upon creation? I use this layer URI: self.pinLayer = QgsVectorLayer( "Point?crs=epsg:3857&field=id:integer&...
2
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1answer
156 views

Making points count automatically when zooming out in QGIS?

Can I make the point count itself when there are too much stacked up points in one area when I zoom out my map? I want my output e.g. Area of ganli points to be like this when i zoom out Water ...
2
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1answer
589 views

Loading WFS GeoJSON from Geoserver in Openlayers

I am trying to load a WFS JSON layer into my web map. I am running the web page on a MAMP server. The layers are loaded from Geoserver and from a POSTGIS database. I have 2 WMS layers being loaded ...
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0answers
122 views

Creating Polygon from groups of points

I have a point feature class (Address Points) and I am interested in creating a polygon feature class around groups of 500 address points. Is there a way I can do this programmatically, as opposed to ...