I'm not entirely sure what you want, but is it "9 5 3" for this data? (9 "new" species occur at the first point, 5 "new" at the second, and 3 "new" at the third). If this is right, then to get "accumulation curve when random Points are considered", you can probably just index rows of dt appropriately.
> dd <- read.table("clipboard", header=T) > dd[,1:3] Point species frequency 1 7 American_elm 7 2 7 apple 2 3 7 black_cherry 8 4 7 black_oak 1 5 7 chokecherry 1 6 7 oak_sp 1 7 7 pignut_hickory 1 8 7 red_maple 1 9 7 white_oak 5 10 9 black_spruce 2 11 9 blue_spruce 2 12 9 missing 12 13 9 Norway_spruce 8 14 9 white_spruce 3 15 12 apple 2 16 12 black_cherry 1 17 12 black_locust 1 18 12 black_walnut 1 19 12 lilac 3 20 12 missing 2 > # dt: table of which species occur at which "Points" > dt <- table(dd$Point, dd$species) > # doc: for each species, the index of the "Point" where > # it first occurs > doc <- apply(dt, 2, function(x) which(x==1)[1]) > doc American_elm apple black_cherry black_locust black_oak 1 1 1 3 1 black_spruce black_walnut blue_spruce chokecherry lilac 2 3 2 1 3 missing Norway_spruce oak_sp pignut_hickory red_maple 2 2 1 1 1 white_oak white_spruce 1 2 > table(doc) doc 1 2 3 9 5 3 > hope this helps, Tony Plate Steven K Friedman wrote: > Hello, > > I have a data set with 9700 records, and 7 parameters. > > The data were collected for a survey of forest communities. Sample plots > (1009) and species (139) are included in this data set. I need to determine > how species are accumulated as new plots are considered. Basically, I want > to develop a species area curve. > > I've included the first 20 records from the data set. Point represents the > plot id. The other parameters are parts of the information statistic H'. > > Using "Table", I can construct a data set that lists the occurrence of a > species at any Point (it produces a binary 0/1 data table). From there it > get confusing, regarding the most efficient approach to determining the > addition of new and or repeated species occurrences. > > ptcount <- table(sppoint.freq$species, sppoint.freq$Point) > > From here I've played around with colSums to calculate the number of species > at each Point. The difficulty is determining if a species is new or > repeated. Also since there are 1009 points a function is needed to screen > every Point. > > Two goals are of interest: 1) the species accumulation curve, and 2) an > accumulation curve when random Points are considered. > > Any help would be greatly appreciated. > > Thank you > Steve Friedman > > > Point species frequency point.list point.prop log.prop > point.hprime > 1 7 American elm 7 27 0.25925926 -1.3499267 > 0.3499810 > 2 7 apple 2 27 0.07407407 -2.6026897 > 0.1927918 > 3 7 black cherry 8 27 0.29629630 -1.2163953 > 0.3604134 > 4 7 black oak 1 27 0.03703704 -3.2958369 > 0.1220680 > 5 7 chokecherry 1 27 0.03703704 -3.2958369 > 0.1220680 > 6 7 oak sp 1 27 0.03703704 -3.2958369 > 0.1220680 > 7 7 pignut hickory 1 27 0.03703704 -3.2958369 > 0.1220680 > 8 7 red maple 1 27 0.03703704 -3.2958369 > 0.1220680 > 9 7 white oak 5 27 0.18518519 -1.6863990 > 0.3122961 > 10 9 black spruce 2 27 0.07407407 -2.6026897 > 0.1927918 > 11 9 blue spruce 2 27 0.07407407 -2.6026897 > 0.1927918 > 12 9 missing 12 27 0.44444444 -0.8109302 > 0.3604134 > 13 9 Norway spruce 8 27 0.29629630 -1.2163953 > 0.3604134 > 14 9 white spruce 3 27 0.11111111 -2.1972246 > 0.2441361 > 15 12 apple 2 27 0.07407407 -2.6026897 > 0.1927918 > 16 12 black cherry 1 27 0.03703704 -3.2958369 > 0.1220680 > 17 12 black locust 1 27 0.03703704 -3.2958369 > 0.1220680 > 18 12 black walnut 1 27 0.03703704 -3.2958369 > 0.1220680 > 19 12 lilac 3 27 0.11111111 -2.1972246 > 0.2441361 > 20 12 missing 2 27 0.07407407 -2.6026897 > 0.1927918 > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html