Michael, Â the code for converting a data frame containing UTM coordinates identified by group, into SpatialPolygon objects, works spectacularly well. Many thanks --Seth
----- Original Message ----- From:Michael Sumner To: Cc: Sent:Mon, 16 Jul 2012 16:30:46 +1000 Subject:Re: [R-sig-Geo] Converting UTMs to SpatialPolygons object Here we go, I'm assuming each ring is its own simple object, and a few other things. id = rep(seq(1,3),each=12) az = rep(seq(0,359,30),3) ## assume you meant to use all ids here? d = dataframe(id [1],az) d$dist = round(rnorm(36,10,3),1) xp = function(azimuth, r){cos(((90-azimuth)*pi)/180)*r} yp = function(azimuth, r){sin(((90-azimuth)*pi)/180)*r} ctr_e = rnorm(3,667314,50) ctr_n = rnorm(3,4784480,50) d$utm_e = round(xp(d$az,d$dist),1) + ctr_e[d$id] d$utm_n = round(yp(d$az,d$dist),1) + ctr_n[d$id] library(sp) myCRS = CRS("+proj=utm +zone=18 +ellps=WGS84") ## create list of coords, including repeat of first row for each l.coords [2] az = rep(seq(0,359,30),3) # Generate > azimuth sequence > c = data.frame(id [11] > [1],az) # Combine in > data frame > c$dist = round(rnorm(36,10,3),1) # Generate random distances from > center of polygon > > xp = function(azimuth, r){cos(((90-azimuth)*pi)/180)*r} > # Function to calculate horizontal distance from polygon > center > > yp = function(azimuth, r){sin(((90-azimuth)*pi)/180)*r} > # Function to calculate vertical distance from polygon > center > > ctr_e = rnorm(3,667314,50) # Randomly select eastings > for polygon centers > ctr_n = rnorm(3,4784480,50) # Randomly select northings for > polygon centers > > c$utm_e = round(xp(c$az,c$dist),1) + ctr_e[c$id] # Calculate > point eastings > c$utm_n = round(yp(c$az,c$dist),1) + ctr_n[c$id] # Calculate point > northings > > myCRS = CRS("+proj=utm +zone=18 +ellps=WGS84") # define > proj4string > > Appreciatively, > > Seth Bigelow > > > > Links: > ------ > [1] http://sitemail.hostway.com/http:/ [12] > > > [[alternative HTML version deleted]] > > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org [13] > https://stat.ethz.ch/mailman/listinfo/r-sig-geo [14] > -- Michael Sumner Hobart, Australia e-mail: mdsum...@gmail.com [15] Links: ------ [1] http://sitemail.hostway.com/http:/ [2] http://l.coords/ [3] http://sitemail.hostway.com/http:/ [4] http://l.polygons/ [5] http://sitemail.hostway.com/http:/ [6] http://sitemail.hostway.com/http:/ [7] http://sitemail.hostway.com/http:/ [8] http://sitemail.hostway.com/http:/ [9] http://sitemail.hostway.com/http:/ [10] http://l.polygons/ [11] http://sitemail.hostway.com/http:/ [12] http://sitemail.hostway.com/http:/ [13] mailto:R-sig-Geo@r-project.org [14] https://stat.ethz.ch/mailman/listinfo/r-sig-geo [15] mailto:mdsum...@gmail.com [[alternative HTML version deleted]]
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