Tag Info

Hot answers tagged

11

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 ...


8

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) ...


8

I found this metadata file indicating: C = County I = Interstate M = Common Name O = Other S = State recognized U = U.S.


8

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 ...


6

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). ...


6

I'll try to analyze your use cases from a QGIS perspective: Software that allows me to drive a specific route and store that as a working model. There is a GPS Tool for live tracking of GPS devices. But I guess you could go with the simpler version of loading the recorded GPX files into QGIS after collection. Download some GPS/County information to ...


6

This paper by Koichi Yagi shows how the accelerometer in a smart phone can be used to measure roughness. Update Whatever software you end up using, I think it needs the ability to manage road condition surveys. An important role of pavement management is prioritizing road repairs and deciding when to re-surface instead of repair. I'd like the road in ...


5

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 GIS desktop and/or web solution would help you answer these question. you could use something like QGIS or GeoServer as a desktop or web solution. to get accurate county road data you could see if the county has a GIS department to obtain data. If not most States have a open clearinghouse GIS web site to download data or you could possible get data from ...


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

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 ...


4

I think that "node centrality" concepts, in the graph theoretic literature, may be helpful. Here is an introduction to centrality measures in graphs.


4

You could try the Identity tool, using your line features as the input, and polygons as the identity features: "When the Input Features are lines and the Identity Features are polygons, and the Keep relationships parameter is checked (relationship set to KEEP_RELATIONSHIPS), the output line feature class will have two additional fields, LEFT_poly and ...


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 ...


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 ...


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 ...


2

This seems to potentially answer your question: https://github.com/bbecquet/Leaflet.PolylineDecorator I can't' comment on the appropriateness of the method... seems like a lot of code for a simple problem.


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

It's not going to be as easy as you expect. Firstly you need a data source. Your best option for this is OpenStreetMaps' Database. But if you take the entire world, the data is in 100s of GBs. Secondly, you will need a source for your cities. You will need a polygon source, which indicates the boundary of the city, so that you can then select the streets ...


2

If you want to use ESRI Technology you'll need network data set at your data base. The second important component is server and a application for this You'll need ArcGIS Server to publish it to the internet. and a website.


2

A robust method to match networks is described in Mustière, S., Devogele, T., Dec. 2008. Matching networks with different levels of detail. GeoInformatica 12 (4), 435-453.. It has been used at the French national mapping agency to match 2 geographical databases with different levels of detail (see image below). The purpose was to do exactly what you need: ...


2

You can download the road network for Northern Ireland from Cloudmade in shp or osm format. Please check out http://downloads.cloudmade.com/europe/northern_europe/united_kingdom/northern_ireland#downloads_breadcrumbs


2

What you're trying to create is either a categorized or graduated symbology. This website walks you through it: http://qgis.spatialthoughts.com/2012/02/tutorial-styling-vector-data-in-qgis.html


1

QGIS comes with an OSM plugin which can open .osm files or download smaller regions directly from the web. The result is immediately visualized. Large .osm files will take long to parse. Tags will be written to the attribute table where you can use the usual QGIS query building tools to filter features. Note that the OSM plugin in QGIS 1.8 is far from ...


1

If you want to bring both the points and the roads into a spatialite database, then you can use the ST_Distance function to find points within a certain threshold from the roads: SELECT p.* FROM points AS p, roads AS r WHERE ST_Distance(r.geometry, p.geometry) < threshold GROUP BY p.id; (The GROUP BY will insure that if a point is within the threshold ...


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

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/



Only top voted, non community-wiki answers of a minimum length are eligible