I'm trying to built a network dataset for Da Lat, Vietnam for an urban planning project. I went to www.openstreetmap.org and downloaded file by choosing OpenStreetMap XML Data export format. The file stored on my PC has a .osm extension. When I ran OSM2NDS, it required me to put a .osm and a .xml file in order to build a network. How do I do that? Do I need to download a .xml file? How so?
the xml file required is used to set the parameters for the network
datasat, e.g. if you want to calculate it for cars or pedestrians. I
remember downloading it from the 52north website, where i downloaded
osm2nds as well, but after a quick search, i cannot find it right now.
It seems like they rebuild their website somehow. I have the xml file
for pedestrians on my pc and could send it to you, but i guess Eva is
reading this mail as well, so she maybe knows more about where to get
the correct xml-files.
> Hello everybody,
> I'm trying to built a network dataset for Da Lat, Vietnam for an urban
> planning project. I went to www.openstreetmap.org and downloaded file by
> choosing OpenStreetMap XML Data export format. The file stored on my PC has
> a .osm extension. When I ran OSM2NDS, it required me to put a .osm and a
> .xml file in order to build a network. How do I do that? Do I need to
> download a .xml file? How so?
> I'm using Arcgis 10, SP 3 on Windows 7
> Help is much appreciated
> View this message in context: http://osm2nds.forum.52north.org/how-get-xml-files-from-OSM-tp4639422.html > Sent from the 52°North - OSM2NDS Forum. mailing list archive at Nabble.com.
> Osm2nds mailing list
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OpenStreetMap has implicit and explicit traffic rules. The tags at the objects (in the OSM file) represent explicit traffic rules. Implicit traffic rules are not tagged. Instead the object type implies the traffic rules. Example: The road class highway=cycleway implies that pedestrians do not have access (foot=no). foot=no does not have to be tagged because the road class implies this rule. If pedestrians should have access to this cycleway, the implicit rules must be overwritten. Then the OSM object has to be explicitly tagged with foot=yes. This explicit rule overwrites the implict rule.
Implict traffic rules are sometimes defined in the OSM Wiki for different countries and transportation modes. However, this documentation is not complete. As OpenStreetMap allows to capture any kind of attributes/tags, the object types are not restricted. This makes it impossible for osm2nds to provide the implicit traffic rules for all road classes and barrier classes. This is the reason why there is a configuration file (parameter file). This configuration file should contain all relevant implicit traffic rules for the current network/OSM file. I have generated some sample files for the traffic rules in Germany (http://52north.org/communities/geoprocessing/osm2nds/configuration.html). Osm2nds checks if the implicit traffic rules are defined for all object types of the current OSM file. If implicit rules are missing, default values are used which are pre-defined in the configuration file. Additionally, a warning is logged in the log file.
Example: The implicit access restriction for highway=cycleway could be missing in the configuration file for pedestrians. Then the pre-defined default value, e.g. foot=yes, is used. However, the OSM Wiki says that highway=cycleway implies foot=no. If you do not change the configuration file, all cycleways without an explicit access tag are open for pedestrians. This isn't intended by the user.
Therefore it is recommended to do the conversion process twice to get an optimal result. After the first conversion you should study the log file and update the configuration file according to the warnings in the log file. Then you should convert the network again.
Thank you very much for your fast and detailed reply.
I used the motorcar xml for Germany and successfully created a network dataset. Vietnamese and German traffic rules are quite similar, so I guess I will make minor changes in the log file. Now I can start working on the analysis.
Thank you for explaining the xml format so clearly, I had no clue what it was and what to do with it before.
I highly appreciate your work and you contributions, this is a very powerful tool and it will help tremendously with our work on the urban plan.