equation query by jim regetz
Attached are three files...
spcodes_auto.csv:
- Basically the same thing as Table 4, with a new column added that
combines the first two letters of genus and first two letters of
species. Some human intervention required to ensure that these codes
correspond to the desired codes in the Equation Library table (below).
sp_eqlib.csv:
- The subset of tree ("T") species with equations that can be calculated
solely from DBH. Species codes and species descriptions are both
included. There are multiple rows per species, one per response
variable. This is from the *old* BIOPAK equation library.
biomass.r:
- An (as yet incomplete) R script intended to extract equations from the
BIOPAK equation library, parse them into executable R functions, and
apply them appropriately to the individual tree records in the
"FIA_indivtrees.csv" file.
The code is mostly working (in prototype fashion), but some issues are:
- Matching up of species codes in the FIA data and in the equation
library is imperfect. Several issues still to work out here.
- In cases where there are more than one equation for the same quantity
for a particular tree species, the code currently just takes the
mean of the different outputs
- Parts of the code might break if you change things like column
headers, etc. This could be handled easily enough with function
arguments, but for the most part isn't yet.
- Speed problems: The cast/melt statement that converts the final list
into a table is slooooooowwwww on the full 230k+ record FIA dataset.
Note that everything before that happens in <10 minutes, which is
not great but probably fast enough. Almost certainly can do some
things to make the code faster if necessary. Also note that
performance would probably get worse if you wanted more advanced
logic about which equation to use in particular cases.
I had hoped to send a first cut of results, but...it's still running.
Hope this is a good start!
Jim
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