An interconnected set of points and lines that represent possible routes from one location to another, OR in computing, a group of computers connected in order to share software, data, and peripheral devices, as in a local or wide area network.

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2
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0answers
22 views

QGIS Broken Link to files on a server

My colleagues and I are using different versions of QGIS (2.8.2, 2.86 & 2.14) on windows 8.1 and Windows 10. When we open existing projects we get a "Handle Bad Layers" box coming up. We have ...
1
vote
0answers
25 views

Looking for an algorithm to quickly find the closest point on a road network (or other graph)

I am looking for a fast algorithm that will find the closest point on a line segment in a graph (such as a road network) to my test point. I'll try to be more specific. I have a road network graph. ...
1
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0answers
17 views

Qgis network prepare road graph

I have been working on finding shortest path between two buildings. For that purpose i have created kml files of various streets, converted them into shape files and then merged all of them together. ...
1
vote
1answer
14 views

QGIS, Calculate networks first, diameters second

I need to get the following task done: First, various points (stored in a shapefile, identified by a common attribute) need to be put into relation with each other (see graphical scheme, steps 1 and ...
2
votes
1answer
211 views

How to use GRASS v.kernel to calculate point densities along a network?

In a road network, I need to select the segments where a minimum of 5 dots occur (1 dot = 1 address) over a distance of 100 m (the image attached illustrates my question). I'm trying to use GRASS ...
3
votes
1answer
296 views

Route to cover entire network

I have a road network where I have to cover every road for visual inspection. I need to design a route map for this task. What tools are available to a QGIS user? How would you describe the workflow ...
6
votes
4answers
128 views

PostGIS query for selecting features not connected to rest of road network?

I have a dataset of roads in a city stored in a PostGIS enabled database. I would like to identify and remove any feature which is not connected to the rest of the road network. This behavior is ...
2
votes
1answer
43 views

Expand Street Network passing through points using QGIS?

I have a road network (red) passing through some traffic data points (green): I want to expand this network to include all of the points. I already have a bigger street network (blue) from which I ...
1
vote
0answers
33 views

Calculate shortest paths for each output area in catchment through road network to a single point (i.e. store)

The title sums it up pretty much. I'm looking to derive trip distributions to a single store using population data and distance within a prescribed distance catchment. I have calculated the catchment ...
2
votes
1answer
104 views

How to use the Grass modules v.net.xxxx from within QGIS

I'm trying to create a an area that can be reached within a certain amount of time/distance from a single (or multiple) points. To do this i'm using the GRASS tool v.net.iso (via the GUI). I've ...
2
votes
1answer
29 views

Can I use Mapbox to create a web form that finds parks near a location?

I have run a network analysis in ArcGIS and have all of the trimmed polygons along roads within a half a mile of a park. I need to find a way to create a web form that takes in an address and spits ...
14
votes
7answers
8k views

Which tools and methods can be used to create isochrones?

I'd like to get an idea for what's involved in creating isochrones for a series of sites, with a reasonable degree of accuracy to the estimates. A general outline would be great, though my scenario ...
1
vote
1answer
25 views

ArcMap 10.1 Create colored lines from one layer to another based on common field

I joined a points layer to a polygon layer. How can I draw lines from a one-to-many polygon to points? I don't have Business Analyst extension so I don't think spider diagram is the right tool. Also, ...
1
vote
0answers
16 views

QGIS-streets network: How to get the points equistant at a certain distance from one point given?

Into a network of streets (let’s suppose polilines or polygons): How to get the points equistant at a certain distance from one point given? I know how to do this with ArcGIS with Network Analyst ...
55
votes
11answers
21k views

Creating drive time polygons using Open Source tools?

Is anyone using open source tools and/or data to generate drive time polygons that radiate out from a given location? For example, I have used ESRI products like Network Analyst and Business Analyst ...
1
vote
0answers
18 views

Nominatim installation - network flood

I've tried to install Nominatim with a planet.pnf file to a server which is hosted at Dacentec(36gb ram, 16 threads, 1x2TB 7200 RPM hard). The installation was going well, it was already indexing data ...
-1
votes
1answer
71 views

Mean centre on the roads network

I am trying to evaluate the current police stations. so I want to find the mean point of crime points in the city and compare the OD cost matrixes of the results. Is there any way to find the mean ...
0
votes
0answers
35 views

'D8 contributing area method' - TauDEM with QGIS

I'm using the TauDEM on Qgis to extract drainage area network from DEM. I could do it easily using the threshold method of TauDEM. Now I would like to do it using a shapefile of the inlets of the ...
2
votes
0answers
40 views

Roadnetwork_merging [closed]

I have a shapefile of a road network which has two lines to represent the two-way directions. My attribute consists of "fromnode", "Tonode", "length", "One-way" (every cell has a value of one here, ...
3
votes
1answer
47 views

QGIS: sewer system symbology

Is there any symbology set out there for sewer systems or other piped networks? The sort of elements I need to represent are: Conduits Junctions Pumps Weirs Outfalls Gates etc... There are few ...
2
votes
1answer
49 views

Creating isochrones in ArcGIS for Desktop?

Is it possible to create isochrones (lines of equal travel time to or from a certain point) in ArcGIS? I have a street network, with the streets having a speed limit attribute, and I need to create a ...
0
votes
0answers
34 views

Network Analyst line barriers have no network location?

I am using ArcGIS Network Analyst to calculate a route between two points on a road network. I have added a number of scaled cost line barriers but no matter how I mess with the settings, solving for ...
2
votes
0answers
62 views

Global shipping network datasets for download?

Does anyone know if global shipping routes for free download (preferably ESRI shapefile) exist? I would need them for my research only as a background presentation on the world image. They can be ...
1
vote
0answers
21 views

Convert a polygon grid into an edge table

I'm working on a robotics project. I've got a rectangular grid (polygon shape file) that is a navigateable/routable region (i.e. I can travel anywhere in this grid). That is I took my bounding area ...
1
vote
0answers
24 views

Build network based on shortest distance between points

Is there a way to build a network based on the shortest distances between each point of a point layer. I have occurrence data from species (as points) and want to estimate whether there are one or ...
2
votes
0answers
32 views

Create network graph from contiguous polygons in KML, or PostGIS?

I am using Postgres 9.5 and PostGIS. I have a table with a geometry field. This table has about 200 rows, in each of which the geometry field contains a Polygon. I would now like to derive an ...
0
votes
0answers
53 views

Create matrix measuring distance from each point to every other point along polylines

I'm working on a project involving ancient trade routes. I have two datasets: 1) -Nodes (around 1000): Every node has a nodeID, lon, and lat 2) -Arcs (several hundred): contains a record for each ...
15
votes
3answers
6k views

How to calculate Network Service Areas in QGIS?

Is there any way in QGIS to apply service area buffers e.g if I have a point on a map I wish to show the service coverage of 1 mile, 2 mile, 3 mile, breaks using the road network?
1
vote
3answers
255 views

Creating network datasets from OSM data in QGIS?

I am having a difficulty to use network analysis in ArcGIS because of unavailable network datasets. So, I googled it and realized that it is possible by using OpenStreetMap. However I don't know how ...
2
votes
0answers
34 views

Buffer for network roads in QGIS [duplicate]

How can I create "buffers" or vector from values ​​from a layer of points, where the "buffers" are "tied" to the streets? Example: A bus station, I would like to create vectors within 100 m range ...
3
votes
0answers
37 views

Calculating a specific distance from points along a network - GRASS

I'm currently using the v.net.iso function in GRASS (no access to network analyst in ArcMap). Does anybody know of a way to export the result to shapefile so that you have an individual line ...
6
votes
3answers
669 views

Network distance computations using GRASS

I'm an ArcGIS user who's interested in learning to use GRASS. Can anyone point out resources that will help me in learning how to obtain network distances between (1) residential locations (points) ...
5
votes
1answer
690 views

Road Topology Problem solution for junction

I am working with a Road Network. I have digitized the lines with AutoCAD Map 3D. Then Imported it to ArcMap. After entering all kind of database I have created Routing Dataset. But unfortunately its ...
3
votes
1answer
218 views

QGIS 2.6 simplify a road network to obtain the intersections

In QGIS 2.6.1 in Ubuntu, I want to measure the density of block in this city (FYI my final aim is to measure the TOD level). I have the road network from French national IGN dataset BDTopo. I have ...
27
votes
11answers
8k views

Alternatives to pgRouting

I was wondering if there are any alternatives to pgRouting tools. Thinking about it for a bit, I think the only alternative is to use R or RPY to do the analysis. Basically I'm trying to solve ...
7
votes
2answers
709 views

Is there an open source tool to planarize graphs?

I read about the planarize function in ArcGIS, which seem to do exactly what I want. Is there a similar feature in QGIS or another free tool? I have a shapefile with various shapes intersecting each ...
1
vote
1answer
19 views

Any standards for urban rainwater drainage network?

I am starting to work on a project related to urban drainage networks. Are there any standards out there to represent this kind of network? Relevant attributes would be things like pipe section, pipe ...
0
votes
0answers
24 views

Live GPS tracking with both ping script

That's a professional context : During a travel between two train station, I would like to use the live tracking and analyse the network performance (access by Wifi & 3G/4G ). I would like to ...
3
votes
0answers
67 views

How are costs returned by the pyQGIS implementation of Dijkstra calculated?

How are the costs returned by pyQGIS implementation of Dijkstra (QgsGraphAnalyzer.dijkstra) calculated? As far as I know, these costs correspond to the distance from the starting node to each of the ...
1
vote
0answers
35 views

Geoserver VM with NAS, Should I store entire VHD on the NAS or just map the data directory? Or just go with internal SSDs w/ weekly backups?

Our humble geoserver instance needs to be able to host GEOTIFF image pyramids ranging in size from a few gigs to a few TBs. A NAS appliance with raid 10 seems smart from a maintenance/expandability ...
8
votes
2answers
2k views

Selecting only canals that are connected to reservoirs?

I have a polygon layer of water reservoirs and a polyline layer of canals. In my data, some canals are originating from reservoirs, and leading to other canals. On the other hand there are some ...
8
votes
3answers
1k views

How to create an OD road distance matrix in QGIS?

I'm looking for the steps required to produce an origin-destination (OD) cost matrix. What I'm looking for is a matrix of road distances. The distance matrix tool only produces euclidian distances. ...
4
votes
2answers
168 views

Road segments reconstruction from GPS trajectories

We have a 10,000 base of vehicle mounted moving devices which report their GPS position on a time based schedule. All that data is currently being stored in our database for several business related ...
2
votes
3answers
232 views

Creating a simulation of how people moving around a site

I am working on a project aiming to create a geographic simulation for how people interact around a site. Situation: There are x people in an enclosed area (such as a zoo). There are y locations to ...
3
votes
1answer
40 views

Get upstream sections of a network

Is there any extension to get all upstream sections of a polyline shapefile which represent an hydrographic network in QGIS? It could work like this: you choose a specific branch and a direction ...
1
vote
1answer
38 views

Navigating a road network and avoiding u-turns

I've implemented a node-based A* search of a road network graph. I would like to penalize u-turns a places where bi-directional streets join together again, which I identify successfully via a match ...
2
votes
1answer
70 views

Reproducing GRASS GIS network analysis tutorial in QGIS Field Calculator

Im looking to reproduce the assigning of road speeds as denoted in a GRASS GIS tutorial (v.net.alloc tutorial), where the road speed is assigned by road type (i.e. 'interstate' = 75 mph etc.) to then ...
4
votes
0answers
26 views

“Merging” 2 layers of LineString with splits at intersections

I would like to "merge" 2 networks of lines and these lines need to be split when they intersect. With pictures it should be clearer : What to do: if a black line intersects a red line, they ...
0
votes
0answers
17 views

Nested Set Model for Spatial Data?

How can I create a nested set model for a spatial line dataset? The nested set model is a technique for respresenting hirarchies of a tree (see https://en.wikipedia.org/wiki/Nested_set_model). If ...
1
vote
1answer
67 views

ArcGIS Online Network Service

Where does ArcGIS Online Network Service source came from? Is there any source reference I can refer to? I tried to search on Google but I could not find anything.