Thanks Melanie, That is a great, workable solution. Thank you...I'll try that!
Tina On Jul 8, 2016 4:59 PM, "Bacou, Melanie" <m...@mbacou.com> wrote: > Seems the simplest might be to use the circle that contains your points' > bounding box (same center as the bbox and with a diameter equal to its > diagonal? > Spatial circles may be defined as SpatialPolygonsDataFrame using > sampSurf::spCircle(). > https://cran.r-project.org/web/packages/sampSurf/sampSurf.pdf > --Mel. > > > On 7/8/2016 10:31 AM, Tina Cormier wrote: > >> Hi all, >> >> Looking for help aggregating some field data subplots to the plot level >> (data currently in shapefile format). I have clusters of 4 points (4 >> subplots = 1 plot). I'd like to create a circle around each cluster that >> is >> the smallest circle that would encompass all 4 points. Sort of like a >> convex hull, but a circle (convex hull, in this case, would give me a >> triangle because of the layout of the subplots). I am familiar with (and >> use frequently) the typical geo packages in R - with rgdal, sp, raster, >> and >> maptools being my most frequent flyers. Is there a function I'm missing in >> these (or some other) packages that might be able to help me out? In the >> attribute table, I have a unique ID for each plot/cluster. So for each >> plot >> ID (in this case, consisting of 4 subplots), I'd like to build a circle >> around all of the subplots. >> >> str(pts) >>> >> Formal class 'SpatialPointsDataFrame' [package "sp"] with 5 slots >> ..@ data :'data.frame': 160 obs. of 12 variables: >> .. ..$ Plot : num [1:160] 1 1 1 1 2 2 2 2 3 3 ... >> .. ..$ Subplot : num [1:160] 1 2 3 4 1 2 3 4 1 2 ... >> >> I should also mention that it's not always 4 points (subplots), and they >> aren't always covering the same size area on the ground, so buffering by a >> constant distance isn't the answer. I have subset out 3 plots (so 12 >> subplots) into a test file here: >> https://dl.dropboxusercontent.com/u/72421241/test_subplotsToPlots.zip >> >> I have R version 3.3.0. I know it's customary to include code for what >> I've >> tried, buuuut, that would be a blank canvas at this point. Googling hasn't >> really been fruitful for this issue, so I thought you folks might have >> some >> good ideas! >> >> Thanks, >> Tina >> >> [[alternative HTML version deleted]] >> >> _______________________________________________ >> R-sig-Geo mailing list >> R-sig-Geo@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo >> > > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
