17
votes
Accepted
Finding disconnected islands in road network layer using QGIS
Based on Detlev's answer, I have developed a QGIS plugin which should allow others to solve similar problems easily. It is available in the official QGIS plugins repository and can be found in the ...
- 658
7
votes
Accepted
Routing with several stops using QGIS
The solution requires some basic usage of PyQGIS. This code computes paths for every subsequent pair of points using the order specified in the "order" field. Then all the paths are merged ...
- 1,598
5
votes
Properter to get travel time as cost for network analysis
Here's a short Properter which I'm working on that might provide part of the answer. It aims to modify shortest path calculations for a road network by excluding freeways (because I'm using it for ...
- 361
5
votes
Finding disconnected islands in road network layer using QGIS
You can use Python module networkx for this.
The following script reads the polyline layers and creates an undirected graph. Networkx function connected_component_subgraphs() determines to which ...
- 4,558
5
votes
Automating the selection of starting points in calculation of Shortest path (point to layer) in QGIS
A solution using the PyQGIS.
Let's assume there are three layers, see the image below:
start points : three red dots in the 'random_points_test' layer
end points : three blue dots in the 'points_test'...
- 31.3k
3
votes
Accepted
Properter to get travel time as cost for network analysis
This is the properter that I put together from all the properter-examples that were posted. It works well. Note that the defaultSpeed is not used in my case (for peculiar reasons of my project), but ...
3
votes
Using python QGIS network analysis library to calculate short path based on speed and distance?
I'm using Ubuntu 14.04, QGIS 2.8.1-Wien and python2.7.
Feature.attributeMap() does not work.
After much struggles with the undocumented way of implementing new ArcProperter's, here is my working ...
- 151
2
votes
Using python QGIS network analysis library to calculate short path based on speed and distance?
I think you don't need QVariant. I'm trying to create my own Properter for bike trips which (as a start) excludes freeways and roads that haven't been built yet. In my road layer, these are ...
- 361
2
votes
Network analysis using QGIS?
The easiest way (at least for me) was to use GRASS for this. In QGIS you load the road network and the points (bus stops). Open the tool box (Str+Alt+T) next and search for v.clean and v.net.iso. You ...
- 465
2
votes
Accepted
QGIS Least Cost Distance Points to Destinations via Roads
The solution is to use the GRASS algorithm v.net.allpairs.
See here for documentation.
Also see Spatial distance analysis in QGIS - not all steps are necessary for my solution, but it was most ...
- 812
2
votes
Line network integration analysis in QGIS
I guess the plugin you need is Space Syntax toolkit. It is a QGIS plug-in for spatial network and statistical analysis. It provides a front-end for the depthmapX software within QGIS.
- 1,725
2
votes
Speeding up sDNA analysis
Speeding up analysis locally
First question to ask is do you need betweenness centrality? This is the primary suck of compute time. Switch off betweenness and it's all much faster.
Also, do you ...
- 2,313
2
votes
Checking all 100 km routes through network for proximity to facilities?
I think there are two problems here, not one:
Scenario:
a) Have a Graph (road network)
b) Have charging stations(points)
c)You need a path (set of edges) to calculate distances, from the EV to ...
- 398
2
votes
QGIS network analysis, points on graph cannot be reached
Is your road network fully noded? I.e. has separate lines for every intersection? That's a pre-requisite for the network analysis module.
- 27.4k
2
votes
Accepted
QGIS, Number of Lines through a Point (of over lapping multiline shapefile)
If you have a point layer and a line layer, then you can count the lines near by the points using field calculator:
Open the attribute table of point layer
Open the field calculator dialog (abacus ...
- 7,245
2
votes
Service area/accessibility analysis from point and avoiding polygon layer
Use raster cost approach
The advantage of this approach is that it explicitely excludes land areas and still calculates regions behind island correctly (indirect path around islands).
To calculate ...
- 67.2k
2
votes
Accepted
Setting edge drawing direction-sensitive attribute-based impedance (cost) in QGIS network analysis
Here's a rough approach. Let's assume a very basic network, with three points and three lines. Say you're looking for the Shortest Path (Point to Point) from A to B. The time in seconds in the forward ...
- 3,705
2
votes
Calculating distance between point and polygon in network in QGIS
To calculate the walking distance between each cell in the grid and the nearest football field using your road network in QGIS, you can use the following approach:
Make sure you have your polygon ...
- 21
1
vote
Representing stationary elements in flow map
You can represent these points using a data driven size. To the right of the size field for the points with no movement involved, click on data driven override, select assistant. In the opening panel, ...
- 67.2k
1
vote
Generating edge table from nodes using QGIS
Just a short description, but perhaps it helps to create a workflow. I have worked on such network modelling exercise in ArcGIS Pro, but I am sure there is a similar workflow in PostgreSQL/PostGIS. ...
- 519
1
vote
Considering distance in network analysis (Gephi)
No one offered an answer, so I will add some information that might be useful to others in the future.
I put my data into Gephi in three forms: weighted, with inverse weights, and with no weights.
All ...
- 87
1
vote
Accepted
ArcGIS Online Routing service
The first link you've referenced is a folder, and within that folder is a bunch of services. This is a "Sample Server", as such, it's used to demonstrate different workflows and patterns. ...
- 16.6k
1
vote
Isochrones in R closing roads based on spatial overlays
You might have to build your own OSRM server (docker containers are available, its not too arduous if you know docker) then you'll to get the road data in OSM form and for your study area and load ...
- 62.5k
1
vote
Accepted
Dividing range of territory into squares with different colors from points with accident information using QGIS
You need to make a grid. In QGIS, this is done in the Vector - Research Tools - Create a Grid. The grid should cover the extent of your point data.
For example, if you have the locations of all ...
- 2,060
1
vote
Accepted
Counting population from grid based on travel time
Activate the "buffers" layer
Click on field calculator
Mark "new field", set a valid name for it, select "whole number"
Copy this code in the window:
aggregate('gridd',...
- 3,180
1
vote
Subtracting line features in QGIS
Answering to my own question. I tried a python script made by a friend. It had some issues so finally ended up doing batch processing:
Extracted all the features to individual geopackage layers
Did ...
- 41
1
vote
Seeking Transit Feed (GTFS) Toolset for QGIS?
Using PostGIS, we successfully integrated GTFS data directly into our database and used bus stops to calculate accessibility to students using our existing PGRouting datasets which used street ...
1
vote
PyQGIS3 retrieving points from a shortestpath graph
So the QgsGraphVertex has indeed got changes to it. inArc has become incomingEdges, so the information stated in the [https://qgis.org/api/api_break.html][1] is not necessarily correct.
- 113
1
vote
Cumulative value/cost along shortest distance roads in QGIS
There is a grass tool to calculate the whole distance matrix at once: v.net.allpairs. This tool asks for a layer of "roads" and a point layer an it calculates all the matrix between points. After ir ...
- 3,419
1
vote
Batch distance calculation with v.net.distance
A simple solution: I ran the v.net tool in GRASS GUI to connect the postcodes to the road network, then I ran the v.net.distance in QGISS GUI and it worked; I managed to find out which postcodes are ...
- 355
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