# [postgis-users] Finding/Categorizing Paths from A to B

sub3 steve at subwest.com
Sat May 17 21:02:12 PDT 2008

```Thanks for you quick reply.

>Thoughts below
>
>> I have a bunch of data for driving from point a to b and b to a (home &
>> work).
>> It is GPS data, so it is lat/lon & speed.
>
>Could you specify the format of one piece of data exactly in text?  Is
>it point, line, or polygon?  Samples?

I have a table (called rawdata) with columns of :
Path#,Point#(int),Latitiude(double),Longitude(double),Speed(double),Timestamp,Point
(basically lat/lon in a single point object)

I have a second table called paths:
Path#(int),Line (line object)

So, I really want to find a way to look at the paths table and determine
that paths 1,2,3 I took 1st street. Path 4,5 I took 5th street. Path 6
started going on 1st street then switch over to 5 street.

So if I looked at it graphically on a map, I could easily determine which
paths where which.

>
>> What I don't have is any indication of what paths I took, so I
>> have no idea how to average several trips / path.  From my own
>
>You can aggregate points into lines, which then would give you a path,
>using a group by on a time criteria, for example.
>
>I would try to think in terms of the canonical geographical vector
>model:  is it a point (zero dimension -- like a town in a small scale
>map) , a line (single dimension -- a road in the map), or a polygon
>(like a state boundary).

It would definitely be one line for the full trip. So if I took each point
in the line, and found the
closest point between it and a different line; it would be the same line as
long as none of them differed by too much?  Is that really the best
approach?

>How exactly are you collecting the data -- it might make it easier for
>all of us.
I have a gps feeding into a laptop and capturing the data every minute.

Thanks for you help.

--
View this message in context: http://www.nabble.com/Finding-Categorizing-Paths-from-A-to-B-tp17296462p17299059.html
Sent from the PostGIS - User mailing list archive at Nabble.com.

```

More information about the postgis-users mailing list