Tagged Questions

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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13 views

problems using v.net.allpairs

I am using GRASS 6.4.3, and I am trying v.net.allpairs to do network analysis. I have a line shapefile and a point shapefile, and after I use v.net.allpairs, I type the command d.vect network, and I ...
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0answers
148 views

how to add polylines(routes from public transport) on postgresql(pgrouting) with GUI

After searching a several long time... i decide to ask here for help, im currently using ubuntu 12.04(because of compatibility) with postgresql 9.1, postgis2, pgrouting2 and qgis2.2 i need ...
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0answers
48 views

Topology rules for a 3d network

I am currently writing a spec to which people may end up using to guide the digitization of a large 3d network (exterior pedestrian network + building interiors). In 2d network drawing, it seems to ...
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0answers
24 views

How to add a road to a network dataset

I have a street network file, and I want to add a section of road to it. I start editing on the road network dataset, snapping on, create a new feature line road segment from the edge of the old road ...
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1answer
75 views

How does the tolerance influence QgsGraphBuilder and tieing of points?

I am developing a script which uses OpenStreetMap data to calculate the distance (over the road network) between each building and the nearest hospital. To do this, I mainly follow the official ...
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4answers
123 views

UK road network dataset

Can anybody guide me to a website or a source to download the Geographical UK road network data set. The data set should include the road distances, since I want to apply shortest path search ...
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0answers
105 views

Traversing all possible road routes

I have created a topology from OSM data and would like to simulate a car driving every possible route along the map. The purpose is to "survey" the osm data as if in a car. My ultimate objective is to ...
0
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1answer
76 views

Analysing a network distance to two or more points using GRASS or QGIS

I am doing a piece of analysis work looking at distances along a network in GRASS. Most of the analysis involves finding which parts of the network are within 600m of a series of points. GRASS does ...
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1answer
395 views

How to assign node IDs to links in a network?

I have two shapefile layers in ArcGIS for Desktop 10. I have one line layer and node layer. My node layer(shp) has a "code_1" field and line layer has a "code_node" field. The intersection point ...
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0answers
23 views

Why outside border of a service area is always not reasonable?

In ARCGIS 10.1 network analysis, why results of service area are different if number of break points is changed? For example, the grid is 300m*300m, I try to produce service area around a node. ...
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2answers
59 views

How do I create blocks from a road network?

I have a road network and for every enclosed area within the network I want to create a polygon that represents that area. How does one do this?
1
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1answer
38 views

How to compute drive access to a station based on vehicle origin points? [closed]

I have a shapefile that contains station locations and another shapefile that is the geocoded origins of those who drove to the station. I would like to make a buffer around the station that shows the ...
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1answer
477 views

Read and Export OSM Road Data as a Network of Road Segments [Adjacency Matrices]

I wish to extract from an OSM file a road network, and export it as an array (adjacency matrix) where the nodes are the road intersections and the edges represent the road segments. I don't want to ...
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0answers
160 views

Drawing a road network: offsetting overlapping lines (directed graph)

Say I have a road network defined by a table, indicating, for each arc, its ID, and its head and tail node. In other words, my network is defined as a directed graph. For example, we have two points, ...
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0answers
28 views

How to turn this into a routable network that works with pgRouting? [duplicate]

I'm only asking again since I didn't get any answer and I'm still stuck here... I updated my last question with more info, but it wasn't answered. When I draw a line with snapping enabled and try to ...
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vote
1answer
65 views

How to make pgRouting understand bridges and tunnels?

I have I highway that runs on a bridge over a couple of blocks in a city. How do I get pgRouting to understand that cars can't move from the small blocks on the ground up to the highway on the bridge ...
7
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1answer
263 views

Do ModelBuilder or Geoprocessing tasks run slower if screen locked?

Is it true if you are running ModelBuilder or a geoprocessing task on a large raster\vector dataset then locking the computer would that cause the ModelBuilder or any geoprocessing to run slower? Is ...
3
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3answers
189 views

How to convert Midpoint of Polyline into Point Feature using ArcPy?

I am trying to write a python script to determine flow direction on a water pipe network. I've used this script to find the mid point along each polyline, now i need to convert this data into a point ...
3
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2answers
179 views

Create network from shapefile without ArcGIS?

I want to perform shortest-path analysis on a network whose edges represent real-world roads and whose nodes are buildings or other locations. I have the shapefile for the area I'm interested in. ...
0
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0answers
88 views

Network Analysis-shortest combined distance to one point

First let me confess I have little experience doing network analysis so I assume I know nothing (in essence approach me like my girlfriend does). Anyway, I am attempting to solve what I believe to be ...
1
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1answer
127 views

Creating a point buffer along a road network [duplicate]

I have a road network and have added points indicating fire hall locations. How would i go about creating buffers on those points following the road line. The result am i looking for would create a ...
1
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1answer
70 views

Infrastructure networks in GIS modelling

I am currently working on a GIS-based project which aims to model the interdependency of existing infrastructure networks, e.g. transport, oil, pipeline networks, etc. The network interdependency ...
0
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1answer
688 views

How to build a Spatialite road network from OSM data

I'm looking for algorithm which could help me with building my own road network (for routing) from OSM data. I chose Spatialite DB for this, but here I have only one problem: Spatialite provides ...
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0answers
38 views

Time attribute problems with Network Analyst

My network dataset is in a geographic coordinate system, and when I project into UTM to calculate Miles for a length field to use with my Speed Limits to create a time attribute it does not seem to ...
3
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0answers
85 views

District heating expansion design with ArcGIS [closed]

I am quite new at GIS but I have some experience of the basic concepts involved in a workflow of them. What I currently want to do is to calculate the cost of expanding an existing district heating ...
1
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0answers
112 views

SQL procedure(s) to convert GPS traces to an ordered set of junctions in a network

I have three datasets that I have loaded into a geodatabase (spatialite or PostGIS): A set of GPS points collected from individual trips through urban areas. Points have a unique point id, a group ...
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3answers
630 views

Tracing up a stream network & tabulating attributes of polygons it passes through

I have an ArcGIS question that is either very easy or impossible (my favorite kind). I am somewhat inexperienced when it comes to dealing with network analysis, so maybe I'm missing something major ...
1
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1answer
55 views

how to extract network of city routes from city blocks shape file?

I have a shapefile which contains urban blocks. So, I am going to extract network shapefile of city routes and calculate total length of network arcs. I am using arcgis 10 for this work. Is there any ...
7
votes
4answers
262 views

Automatic matching of two street networks

I'm faced with the problem of matching two street networks. I have these two differently sourced networks. The links in each network can be segmented, i.e. there is not necessarily a single whole link ...
1
vote
1answer
100 views

Find directly joined neighbour points using a different line layer in QGIS

I have two layers of data: A set of points showing every significant point on the UK rail network (Network Rail Stanoxes). These are a mixture of stations, junctions, timing points and signals. An ...
2
votes
1answer
50 views

Conceptually, what's the ideal way to develop detour maps for a large number of nodes

I have a road layer of roughly 30,000 links. On these links, I have a total of 15,000 nodes that are sorted in a point layer. I'm trying to build a detour distance and routing around each asset in ...
2
votes
0answers
369 views

How to specify cost attributes for network analysis in QGIS using the GRASS plugin?

I have a road dataset with information about the length, speed and drivetime for each segment. I use QGIS 1.9 with the GRASS plugin to do different types of network analysis, but how do I set up the ...
0
votes
2answers
113 views

SpatiaLite: Creating to, from nodes from a normal road layer (LINE)

Following this tutorial but using my own data. How do I create the from_node and to_node columns? I am using Spatialite and Sqlite3. I'd prefer to not use a gui as I'm working remotely via ssh on a ...
3
votes
2answers
440 views

Map walking distance/time from transit stops

I'm working in QGIS and would like to show how far from a bus stop a pedestrian could walk along the street network in any direction for a specified set of walking times (5,10,20 mins etc). I have my ...
1
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0answers
48 views

Deleting network features in python script doesn't create net junctions

I have a script that makes a copy of a network dataset for a 3rd party app to use. One of the junction feature classes causes problems with the app. The ideal solution would be to remove it from the ...
1
vote
1answer
131 views

ArcView: Trim polyline, that is shorter than specific dangle length (alternative to tool: Trim Line)?

I am looking for a way to trim dangles from a polyline shape, that are shorter than a specific length like the Trim Line Tool for ArcEditor and ArcInfo, but with ArcView-License. I already discover, ...
1
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0answers
196 views

Calculating walking routes along a network(ArcGIS)

I've created a network consisting of footpaths, dirt tracks and junctions. I would like to calculate a route using network analysis by giving ArcMap the time and walking speed that the route should ...
1
vote
2answers
89 views

How to develop a fastest road website?

I need to develop a website to find the fastest road between two points (just like google map) What kind of technologies I need to use? What are the components of this project (database, website, ...
1
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1answer
88 views

Clipping without cutting features

I want to create a multimodal network dataset for the city of Montreal. I have roads and transit lines features for Quebec province (where Montreal is). Because I need the features limited to Montreal ...
2
votes
1answer
85 views

Why does IDatasetContainer2.CreateDataset fail with ArcObjects at ArcGIS 10.1?

I have a small application used to check and generate network, created with the help of the following tutorial: http://help.arcgis.com/en/sdk/10.0/a...00000w7000000/ It worked just fine with ArcGIS ...
8
votes
2answers
215 views

Spatial Network Cleaning

Data used to create a network from has special considerations when cleaning, as minor spatial errors can lead to major bugs in connectivity. What techniques could be considered best practice for ...
0
votes
1answer
76 views

Adding additional nodes to network in Grass GIS

I have created a network in Grass GIS (using v.net, nodes option). I then want to "disrupt" the network (i.e., create some road blockages) and add in nodes to the new line ends where road blockages ...
1
vote
1answer
269 views

Network Analyst does not take oneway street from attribute table

I want to build a network dataset to calculate travelling times for buses (service area). I have on shapefile with the streets from my home town, which has a column intitled 'ONEWAY', with values of ...
0
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0answers
78 views

How to take point data from a network and input it as TO/FROM endpoint data in streets layer?

I am building a network of my city's roads in ArcMap 10.1. Right now I have three layers: 1) Streets_To-From (lines representing the southbound and westbound sides of every road and one-way streets ...
2
votes
1answer
1k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
1
vote
0answers
167 views

Map Matching? (Finding Nearest Roads…)

I am making Pedestrian Navigation System for my school I created node and arc and digitized buildings with ArcGIS. Then, exported KML to use Javascript Dijkstra's Algorithm to find route. So far, so ...
1
vote
1answer
91 views

Basic traffic volume map [duplicate]

I'm trying to map the volume of people traveling from various cities to popular mountain towns in British Columbia. I have a .csv containing the starting point, ending point and number of travelers. ...
1
vote
3answers
312 views

Merge Multipart Feature Line

I'd try to merge multipart feature line, but didn't work. would you please teach me how to merge multipart feature line? I work in version environmental and geometry network. Regards,
8
votes
3answers
909 views

Howto setup and use a remote GIS workstation (QGIS,GRASS,PostGIS)?

I'm using QGIS (and sometimes GRASS and PostGIS) on my 2009 MacBookPro for my thesis project. I was wondering (during an endless batch generalizing in QGIS) if I can set up a server so I can work from ...
2
votes
1answer
73 views

Clipping a buffer from network analyst shapefile to a base shapefile

I have exported my polygon shapefile which I got after I ran my Network Analyst into a shapefile. It has 6 buffer zones (delimited by time in increments of 10 minutes). When I check the attribute ...