[postgis-users] PostGIS to calculate time spent within polygon
Ralf.Suhr at itc-halle.de
Tue Oct 6 06:47:43 PDT 2009
Hello Masanao Yajima,
for db-design you can go with ogr2ogr (GPX -> PostGIS). Ogr2ogr creates
point and line geometrys from gpx files. In case of linestring you have
to add the 4. Dimension from the point table.
A optimal query would be the intersection from gps-linestrings and your
polygon area. The result can be many sublinestrings with start and end
Von: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] Im Auftrag von
Gesendet: Montag, 5. Oktober 2009 23:03
An: postgis-users at postgis.refractions.net
Betreff: [postgis-users] PostGIS to calculate time spent within polygon
Dear PostGIS users
I am new to PostGIS and I would like expert opinion on how to deal with
I have 2D GPS data and time associated with each points and they
represents line of a trip.
I also have few geographic polygon data representing some area on a map.
what I want to get out is length of time that is spent within polygon
area for a trip.
What is the optimal way to design a database and what kind of query
would you use to get such a number.
One constraint is the time interval for GPS is not accurate so sampling
rate vary alot with in a trip.
I thought of using time as 4th dimension but I believe st_intersection
is not implemented on the 4th dimension..
I could do this by bruit force but I am looking for something fast.
I appreciate your help.
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