Description Usage Arguments Details Value References Examples
Single data frame spatial thinning within an R session.
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ebird.data |
Dataframe of eBird records. |
xxx |
Either E-W coordinates, or the word "extent". If extent is desired, make sure to specify for both xxx & yyy. Function will not handle mixture gracefully. |
yyy |
Either N-S coordinates, or the word "extent". If extent is desired, make sure to specify for both xxx & yyy. Function will not handle mixture gracefully. |
latitude |
The name of the latitude column in the files. |
longitude |
The name of the longitude column in the files. |
xlim |
Together xlim and ylim define a bounding box within which lookup occurs. I.e. all (xxx, yyy) pairs outside of this box are ignored. |
ylim |
Together xlim and ylim define a bounding box within which lookup occurs. I.e. all (xxx, yyy) pairs outside of this box are ignored. |
nx |
Number of grid cells in x direction. |
ny |
Number of grid cells in y direction. |
jitter |
Defaults to FALSE. Set to TRUE to randomize grid location. |
size |
Maximum number of points per cell to sample |
replace |
Defaults to FALSE. Set to TRUE to sample with replacement. |
This applies sample.grid.cell() to single eBird data frame.
A spatially thinned data frame.
Team eBird.
1 2 3 4 5 6 7 | data(ex)
plot(ex$LONGITUDE~ex$LATITUDE, col="blue", pch=20, cex=2)
thinned <- spThinner(ebird.data=ex, xxx="extent", yyy="extent",
latitude="LATITUDE", longitude="LONGITUDE", nx=2, ny=2, size=3)
points(y=thinned$LONGITUDE, x=thinned$LATITUDE, col="red", pch=20, cex=1)
#the blue points are the original data, the red points are the accepted points
#after spatial thinning.
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