Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick
For each point, distance to nearest point in second dataset
7 messages · Nick Eubank, Christopher W. Ryan, Michael Sumner
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike
On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
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Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia [[alternative HTML version deleted]]
Thanks Michael!
Super easy context: two SpatialPointsDataFrames ("voters",
"polling.places"). Each has coordinate columns "x" and "y".
Is it just:
library(nabor)
knn(voters, query = polling.places, k=1)
?
On Thu, May 19, 2016 at 2:59 PM Michael Sumner <mdsumner at gmail.com> wrote:
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
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-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia
For other's reference, that was almost right: To get distance from each voter to closest polling place, the syntax was: knn.results = knn(data=coordinates(polling.places), query=coordinates(voters), k=1)
On Thu, May 19, 2016 at 3:03 PM Nick Eubank <nickeubank at gmail.com> wrote:
Thanks Michael!
Super easy context: two SpatialPointsDataFrames ("voters",
"polling.places"). Each has coordinate columns "x" and "y".
Is it just:
library(nabor)
knn(voters, query = polling.places, k=1)
?
On Thu, May 19, 2016 at 2:59 PM Michael Sumner <mdsumner at gmail.com> wrote:
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia
Last note for future searchers: also suggested was the SearchTree library: http://stackoverflow.com/questions/37333747/for-each-point-distance-to-nearest-point-in-second-dataset-in-r
On Thu, May 19, 2016 at 3:38 PM Nick Eubank <nickeubank at gmail.com> wrote:
For other's reference, that was almost right: To get distance from each voter to closest polling place, the syntax was: knn.results = knn(data=coordinates(polling.places), query=coordinates(voters), k=1) On Thu, May 19, 2016 at 3:03 PM Nick Eubank <nickeubank at gmail.com> wrote:
Thanks Michael!
Super easy context: two SpatialPointsDataFrames ("voters",
"polling.places"). Each has coordinate columns "x" and "y".
Is it just:
library(nabor)
knn(voters, query = polling.places, k=1)
?
On Thu, May 19, 2016 at 2:59 PM Michael Sumner <mdsumner at gmail.com>
wrote:
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
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-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia
See also the spatstat package, and its nncross function. --Chris Ryan
On Thu, May 19, 2016 at 6:48 PM, Nick Eubank <nickeubank at gmail.com> wrote:
Last note for future searchers: also suggested was the SearchTree library: http://stackoverflow.com/questions/37333747/for-each-point-distance-to-nearest-point-in-second-dataset-in-r On Thu, May 19, 2016 at 3:38 PM Nick Eubank <nickeubank at gmail.com> wrote:
For other's reference, that was almost right: To get distance from each voter to closest polling place, the syntax was: knn.results = knn(data=coordinates(polling.places), query=coordinates(voters), k=1) On Thu, May 19, 2016 at 3:03 PM Nick Eubank <nickeubank at gmail.com> wrote:
Thanks Michael!
Super easy context: two SpatialPointsDataFrames ("voters",
"polling.places"). Each has coordinate columns "x" and "y".
Is it just:
library(nabor)
knn(voters, query = polling.places, k=1)
?
On Thu, May 19, 2016 at 2:59 PM Michael Sumner <mdsumner at gmail.com>
wrote:
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia
[[alternative HTML version deleted]]
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On Fri, 20 May 2016 at 08:38 Nick Eubank <nickeubank at gmail.com> wrote:
For other's reference, that was almost right: To get distance from each voter to closest polling place, the syntax was: knn.results = knn(data=coordinates(polling.places), query=coordinates(voters), k=1)
Great! Be sure to use the WKNNF approach to cache the kdtree of the data - it only needs to be done once, but calls to knn obviously will redo that part. Also, you'll probably want to do it with coordinates in a map projection where nearest-neighbour distance makes sense for your domain. Cheers, Mike.
On Thu, May 19, 2016 at 3:03 PM Nick Eubank <nickeubank at gmail.com> wrote:
Thanks Michael!
Super easy context: two SpatialPointsDataFrames ("voters",
"polling.places"). Each has coordinate columns "x" and "y".
Is it just:
library(nabor)
knn(voters, query = polling.places, k=1)
?
On Thu, May 19, 2016 at 2:59 PM Michael Sumner <mdsumner at gmail.com>
wrote:
Use nabor package, it takes a little to learn but is crazy fast. Happy to show if you make a relevant example. Mike On Fri, May 20, 2016, 06:42 Nick Eubank <nickeubank at gmail.com> wrote:
Hi All, Trying to an equivalent to the "nearest" tool in ArcGIS for two SpatialPointDataFrames. I can do the naive implementation by calculating all pairwise distances using gDistance and taking the min, but I have some huge datasets and was looking for something more efficient. (For example, here's a trick with knearneigh for points in same dataset ( http://gis.stackexchange.com/questions/132384/distance-to-nearest-point-for-every-point-same-spatialpointsdataframe-in-r )). Any suggestions? Thanks! Nick [[alternative HTML version deleted]]
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
-- Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia --
Dr. Michael Sumner Software and Database Engineer Australian Antarctic Division 203 Channel Highway Kingston Tasmania 7050 Australia