On Thu, 6 Sep 2012, Nicolas Ribot wrote:
Hi,
Maybe this thread about closing contour polylines can give some hints:
http://postgis.refractions.net/pipermail/postgis-users/2012-May/034149.html
Much thanks. This script is worth exploring.
Do you have sample data we could play with ?
The data that I sourced is here:
National Transportation atlas Database
http://www.bts.gov/publications/national_transportation_atlas_database/
Oak Ridge National Laboratory - CTA Network
http://cta.ornl.gov/transnet/RailRoads.html
I don't have readily available city point data; but that shouldn't be a
challenge in finding.
My thinking now is to try and create a polygon with two endpoint, say
Edmonton and Vancouver, and play with the diameter (20, 40 miles, etc.),
trying to see which rail lines fall within the polygon. Possibly from
that, I can construct a single linestring based some form of ownership
(the BTS data is only for the US; the ORNL data is for North America).
Nicolas
Much thanks again,
Max
On 5 September 2012 19:15, Max Pyziur <p...@brama.com> wrote:
Greetings,
I'm trying to figure out a way of constructing linestrings between
endpoints.
Shapefile data for pipelines and railroads does not present continuous
lines; instead they are in the form of small line segments. The applications
are using data for roads, pipelines, or railroads.
Interstate 70 is not one complete linestring between Washington DC and the
middle of Utah; instead it is a series of segments. The same with pipeline
and railroad data.
The problem becomes more cumbersome (at least to me) when there is no
knowledge of the data between two points (say Edmonton and Vancouver) and
you want to see if there is a way to string a set of segments between two
points (to answer a question like is there a railline between Edmonton and
Vancouver)?
I would appreciate any advice on how to proceed.
Much thanks,
Max Pyziur
p...@brama.com
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