Assuming you only use the X direction to split the data into 10 m cells.
table(list(Species, round(X, digits = -1))) This will generate a table with the number of seedlings per species in each 10 m cell. Divide this by the area of each cell and you get the densities. Cheers, Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature and Forest Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, methodology and quality assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 [EMAIL PROTECTED] www.inbo.be -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Namens James R. Milks Verzonden: dinsdag 12 september 2006 15:36 Aan: [email protected] Onderwerp: [R] Using XY location data to calculate ecological parameters Dear R gurus, I have XY data giving the locations of tree seedlings that were surveyed during a 210 meter belt transect. This belt transect was taken by stretching a line across the field, then measuring all seedlings within 1 meter on either side of the line. The end result was XY coordinates and height for ~1,300 seedlings. I would like to use that data to calculate density of seedlings per 10 meters per species and relative species abundance in order to compare between this transect and other transects as well as to compare between segments of the same transect. Are there any R packages out there that will allow me make those calculations? To give an idea of my data, here's a fictional example: Species X (m) Y(m) Acer negundo 90.10 -.19 Acer negundo 90.14 -.90 Acer saccharinum 90.25 .54 Acer rubrum 90.89 .21 Acer negundo 91.25 .36 Acer negundo 91.46 -.65 etc. Thanks. Jim Milks ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
