R help - Sep 2006 - 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

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

Thierry.Onkelinx op inbo.be

www.inbo.be 

-----Oorspronkelijk bericht-----
Van: r-help-bounces op stat.math.ethz.ch
[mailto:r-help-bounces op stat.math.ethz.ch] Namens James R. Milks
Verzonden: dinsdag 12 september 2006 15:36
Aan: r-help op stat.math.ethz.ch
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

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