G'day All,
I have been struggling to figure out an answer to this question and wasn't sure where else to ask, so here goes. I have a large amount of presence/absence point data (~125,000) with lon/lat coordinates. Like this:
Lat lon abs/pres date
113.6481 -24.90278 0 1/1/1998
113.6481 -24.90278 1 1/2/1998
113.6481 -24.90278 0 1/3/1998
137.5175 -35.69556 1 1/1/1998
137.5175 -35.69556 1 1/2/1998
137.5175 -35.69556 1 1/3/1998
I have been trying to work out a way to identify the cells that each point would fall into if it were mapped onto a raster grid (I am using rasters with the same cell resolution as BIOCLIM rasters). That is, for all points falling within the same cell, I would like to identify them as being a part of the same cell. I am trying to model site occupancy for this species from repeated survey data, using the package 'unmarked', which requires records to be associated with sites. I don't have site IDs with this data so I need to come up with a proxy for this. I thought I could use grid cell id as a proxy for site id, so that all records that fall within the same grid cell can be considered the same site.
How do I identify the grid cell that each point falls into on a raster grid and associate it with my presence/absence data, to produce a dataset that looks like this?
Lat lon abs/pres date cellID
113.6481 -24.90278 0 1/1/1998 234
113.6481 -24.90278 1 1/2/1998 234
113.6481 -24.90278 0 1/3/1998 234
137.5175 -35.69556 1 1/1/1998 250
137.5175 -35.69556 1 1/2/1998 250
137.5175 -35.69556 1 1/3/1998 250
Thanks for your help in advance.
Kind regards,
Adam Cardilini
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