Hot answers tagged road
10
IRIS is one existing open-source solution you should probably be aware of:
From Wikipedia:
IRIS (Intelligent Roadway Information System) is an open-source
Advanced Traffic Management System (ATMS) software project
developed by the Minnesota Department of Transportation. It is used by
transportation agencies to monitor and manage interstate and ...
5
I would recommend using image segmentation with the free software SPRING, available from the Brazilian National Institute for Space Research. Documentation is available here and tutorials are available here. Image segmentation produces high classification accuracy compared to purely pixel based classification methods (e.g. ISODATA, Maximum Likelihood, etc). ...
5
I had to do this just recently. Using ArcGIS 10:
If you only want to symbolise the dead ends you can just set up a Topology on the roads featureclass and set the rule "Must not have dangles". this will put a marker on every feature that has a dead end.
Alternatively, run the "Feature Vertices to Points" Tool (Located in Data Management Tools --> Features) ...
4
As with everythin in GIS there's more than one way to do it:
ArcGIS has a feature to do just this, See Divide line function. Of course, remember that you rarely have an exact division unless you use the percentage option (i.e. you will get a bit left over). And, to be honest, I found it would not always work perfectly but it doesn't do too bad a job. ...
4
I found this metadata file indicating:
C = County
I = Interstate
M = Common Name
O = Other
S = State recognized
U = U.S.
4
Considerations
First thing to consider, you might remove freeways and ramps from your road system before you start, depending on your interpretation of a block or intersection.
First problem is knowing the state of your road system. If road centerlines are split at each intersection and only at intersections, then we proceed with Features Vertices to ...
4
A general way of solving this problem is to find all polylines having a node whose valence = 1.
A valence table may be created either in memory or on disk, using a key that is the hash of the x&y of each end point of each polyline. You may wish to truncate x and y may be truncated if polylines are not snapped.
Each node is labeled by its degree (or ...
4
In ArcGIS Standard or Advanced, you can put your road network into a Feature Dataset in a Geodatabase. You can then set up a topology on the network and create a topology rule which identifies "dangles". This will identify all roads which do not connect to something at one or both ends. Note, this will also identify potential errors in your network which ...
3
Segmented object (aka trained) classification can be used very succesfully for this problem, but I don't know GRASS enough to tell you what capabilities it has in this area. You'd get polygons though, so you'd still have to thin them or use a mean or some other transformation.
You'll get even better results if you have a near-infrared band or composite ...
3
There are a few ways to do this. For the intersections you can use a tool in QGIS (Arc I am sure too) called Line Intersections (Vectors - Analysis Tools). As for the blocks, what I have done for that is to have a polygon of the AOI which covers the entire area. Then I use the roads to cut that polygon into polygon segments. This will give you blocks of ...
2
You can download files for Wales here
http://download.geofabrik.de/openstreetmap/europe/great_britain/
You can download either xml or shape files.
After download you can load files in program like Qgis and select appropriate layers and export them to file or database of your choice.
2
I'm sure you're aware of the nature of Open Street Map - it's a user collected and edited resource. If you're going to use this kind of information it would be largely down to you to fix these - and in the spirit of things update the information!
If you want a relatively clean network for analysis straight away, I'd suggest TIGER.
... but I think you'd ...
2
The Data is not quite there for what you require - but some is...
The TIGER Edited Map maybe of interest to you.
http://wiki.openstreetmap.org/wiki/TIGER_Edited_Map
Red areas are ways which have not been edited since the TIGER import.
Green areas are ways which have been edited.
There still is quite a large amount of fix up required for the TIGER ...
1
As a footnote to this and a shameless author's plug, the free sDNA (spatial Design Network Analysis) plugin for ArcGIS can do this, among other things that may be of interest to you.
You would first need to ensure your network was correctly noded (i.e. all lines breaking where there are junctions; Topology->Planarize can do that).
1
JEquihua,
Try running the Intersect tool in ArcGIS with a single input (the roads) and the output type as POINT; this should give you the number of intersections. As far as the number of blocks, this is just a count of the line segments, if you need to "break" each segment at an intersection look into the Planarize lines feature on the topology toolbar.
...
1
ESRI has a collapse dual carriageway to centerline tool. You can get a cheap version for use with OSM. Otherwise you could select features and save as a new layer. Deleted selected from layer you used for export. Buffer feature within range of one side of the carriageway that includes the second lane. Merge shapefile with original, connect up any broken ...
1
The basic format is the same as any SQL query: select [fields] from [table] where [query]
Here's an example from the osm2pgsql schema page: select name, place, ST_XMin(way), ST_YMin(way) from planet_osm_point where place='city' order by name The schema page should also help you understand the different tables.
But maybe there's something more ...
1
It is possible, but it's not a very efficient way of routing. Very few people would want to use the exact starting & ending point as you. It is much more useful to know which are the roads, which are the directions, and the turns and crossroads.
The problem with services like Google maps in India, is that while traveling, we use a variety of ...
1
I have created this function as a PostGIS implementation of the travel time model. Improvements and suggestions welcomed.
create or replace function public.brabynskellytraveltime(
/*
this is an implementation of Brabyn and Skelly's travel time model for New
Zealand road networks. 1. Brabyn L, Skelly C. Modeling population access to
New ...
1
Linear referencing is the key term to describe the suite of algorithms to do what you want to do. If you want to inspect the source code to the algorithms, check out GEOS (e.g., geos::linearref::LengthIndexedLine Class), or JTS (e.g., com.vividsolutions.jts.linearref).
If you are working with Lat/Long data, you will need to project this to something with ...
1
You could try @underdark comment here, or use the following ESRI/ET Geowizard tool combinations.
ArcGIS/ET-Geowizard
Run Polyline to Point tool using ET-Geowizard, check 'Middle Points' option.
Run Add XY Coordinates tool within ArcGIS/ArcToolbox.
ArcGIS (ArcInfo license)
Run Feature Vertices to Points tool, select 'MID' as point type.
Run Add XY ...
1
Don't know if you've seen this, but this fellow provides an example (albeit a little messy) that works fine too.
http://nodedangles.wordpress.com/2011/05/01/quick-dirty-arcpy-batch-splitting-polylines-to-a-specific-length/
1
Glenn:
oneway = 'yes' is how I understand flow direction limitations in OSM.
OSM shares nodes on intersecting ways. You can detect the ways by checking the reference ids of the nodes.
I have noticed that there are more than a few shared nodes at grade separated crossings which can cause some pretty serious routing issues.
Since much of OSM in the US ...
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