How to get the marked speed limit of a road, out o

问题:

I know that is not a technical question, but I don't know where else to ask.

Is there a way to get the marked speed limit of a road from google or bing maps? or any other web service?

回答1:

You cannot obtain this information from Bing Maps or Google Maps. Nor am I aware of any other webservices that provide this information (certainly not any free ones).

Open Street Map (http://osm.org) has the ability for ways to be recorded with the maxspeed tag. You could download the OSM planet dataset and host it in a spatial database such as SQL Server 2012, then create your own web service to query the database and return the maxspeed of the closest way, but this value is not always reliably filled in. However, even when the maxspeed tag is missing, you can derive an approximate max speed limit by looking at the national speed limit for the type of road in the country of interest, as documented at http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Maxspeed

OSM data varies in quality quite a lot by country. Here in the UK it's really very good - more up-to-date, accurate, and complete than Google Maps or Bing Maps in many respects. However, in other countries it's not so reliable. Alternatively, there are providers that will sell you commercial datasets of road networks containing this information, but they tend to be at the national level and can be very expensive. (What country(s) are you interested in? You don't mention..)

Finally, be aware that this information is fairly dynamic and time-dependent - if you do download a dataset of max road speed information (either from OSM or a commercial source) expect to have to update it frequently to keep up-to-date with highway changes.

回答2:

1. Go to www.google.com/mapmaker .
2. Login or setup an account.
3. Navigate to the area where you want speed limits.
4. Hover over "Edit" and select "Select Road Segments".
5. Select the segment of interest. Suggest you only select one segment at a time.
6. Click on the blue "Next" button in the left hand panel.
7. Select "Edit Road Attributes".

This will bring up a panel on the left-hand side of the page giving you a great deal of information about the segment you selected. In the upper right corner of this panel is the Max. Speed Limit for the segment.

Keep in mind this data is user-generated, reviewed and approved. It can be in error, but is usually pretty close.

回答3:

Wikispeedia.org has been supplying speed limit information worldwide since 2005. Its realtime so you can easily get and manage a cities worth. They get speed limits from States and estimates. Email them and they will hunt for areas you are interested in.

You can just download a box worth like this:

There is a php interface, instant speedlimit for location-aware-broswers and working Java code here:

So to recap, there are three, Navteq, Wikispeedia and OSM. In case you are wondering, there is no Federal or State Speed Limit Database. I have been looking for seven years. They don't exist, that is why wikispeedia was created.