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MARINA84
07-04-2010, 07:58 PM
hello,
I need to know if there is any way to find out if a point with a specific coordinates is located on a specific road. The fact is I am writing a program. I needed to access the road data,like the coordinates of beginning and end of the roads, maybe a complete data base. I did not know how i can access to such an information or file. so for simplicity i assumed some certain vertices and the edges(the connection between the vertixes). now i have a point(a coordinate of a specific location). I want to see on which edge this point is located. I see by just having information abt start n end of vertices and the connection between them (edges=roads) I can not locate a position of a point on the roads.
the thing is my knowledge abt these things is very limited.
I really appreciate any help or suggestion.

many thanks,

Forkboy2
07-05-2010, 06:03 AM
First of all, you can't do that with Google Earth.

Road data is just a bunch of vectors. You'd have to start with the source data (from US Census, OSM, etc).

Once you have start and end point for every line segment, seems like you could figure out if a specific point was on a segment with some basic trigonometry. Not saying I have any idea how to do the programming, but seems like it could be done.

tpstigers
07-11-2010, 03:40 AM
Thought I replied to this before, but apparently I didn't.

You don't need any programming skills to do what you're trying to do. What you need is a basic knowledge of GIS (Geographic Information Systems). There's a bunch of GIS software out there, ranging from tens of thousands of dollars to free (technically, GE is GIS software, but it's not precise enough for this). I would suggest you look into Quantum GIS. It's a solid app with a large support base and decent documentation. Best of all, it's free. Check it out.