I am trying to calculate multiple distances from one set of xy
coordinates to another
using vincenty. In addition to getting those distances, however, I
need to somehow list
the ids for the xy coordinates used to calculate the distance.
Here is the piece of code I'm working with:
code excerpt:
g long rad10=.
g double dist1=.
g id1=""
merge using univpoints00_0
forv i=1/`np' {
qui vincenty `=latitude[`i']' `=longitude[`i']' sch_lat sch_lon, hav(dis)
g within10=dis<10
su within10, meanonly
qui replace rad10=r(sum) in `i'
su dis, meanonly
qui replace dist1=r(min) in `i'
qui levelsof unitid if dis==dist1[`i'], loc(vs)
foreach v of loc vs {
qui replace id1="`v' "+id1 in `i'
}
drop dis within10
}
end excerpt
As you can see, I'm getting a count of all sch_lat and sch_lon
coordinates within a 10
mile radius of the other set of latitude and longitude points. Then I
return only the
minimum distance. Will vincenty allow for returning more than just
the min, max, mean,
or whatever? Or is globdist a better choice for returning multiple
distances and the ids
attached to the point the distance to which is being calculated?
Thanks
David Torres
UMich
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