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Intersect FIA data with spatial polygons

intersectFIA.Rd

Performs spatial intersection between FIA data and user-supplied spatial polygons (sp or sf). Polygon attributes appended to PLOT table, and hence can be used as grouping variables in subsequent calls to rFIA estimator functions. Alternative to the polys argument in rFIA estimator functions.

Usage

intersectFIA(db, polys, nCores = 1)

Arguments

db

FIA.Database or Remote.FIA.Database object produced from readFIA() or getFIA(). If a Remote.FIA.Database, data will be read in and processed state-by-state to conserve RAM (see details for an example).

polys

sp or sf Polygon/MultiPolgyon object; Areal units to bin data for estimation. Separate estimates will be produced for region encompassed by each areal unit. FIA plot locations will be reprojected to match projection of polys object.

nCores

numeric; number of cores to use for parallel implementation. Check available cores using detectCores. Default = 1, serial processing.

Details

All polygon attributes will be joined onto the PLOT table.

Primarily useful if you intend to make multiple calls to rFIA estimator functions, e.g., you need to call both tpa and biomass and group by spatial polygons in both cases. If using the polys argument in each function call, spatial intersection will occur mulitple times, and hence be slower than performing the intersection a single time upfront.

Value

FIA.Database or Remote.FIA.Database, depending on specification of db.

References

rFIA website: https://rfia.netlify.app/

FIA Database User Guide: https://research.fs.usda.gov/understory/forest-inventory-and-analysis-database-user-guide-nfi

Bechtold, W.A.; Patterson, P.L., eds. 2005. The Enhanced Forest Inventory and Analysis Program - National Sampling Design and Estimation Procedures. Gen. Tech. Rep. SRS - 80. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 85 p. https://www.srs.fs.usda.gov/pubs/gtr/gtr_srs080/gtr_srs080.pdf

Stanke, H., Finley, A. O., Weed, A. S., Walters, B. F., & Domke, G. M. (2020). rFIA: An R package for estimation of forest attributes with the US Forest Inventory and Analysis database. Environmental Modelling & Software, 127, 104664.

Author

Hunter Stanke and Andrew Finley

See also

clipFIA

Examples


data(fiaRI)
data(countiesRI)

# Perform spatial intersection
db <- intersectFIA(fiaRI,
                   countiesRI)

# Group estimates by variable defined
# in `countiesRI`
tpa(db,
    grpBy = COUNTY)
#> # A tibble: 30 × 9
#>     YEAR COUNTY       TPA   BAA TPA_SE BAA_SE nPlots_TREE nPlots_AREA     N
#>    <dbl> <chr>      <dbl> <dbl>  <dbl>  <dbl>       <int>       <int> <int>
#>  1  2013 bristol     307.  118.  32.5    7.93           3           3   197
#>  2  2013 kent        535.  132.  16.8    6.40          14          14   197
#>  3  2013 newport     325.  122.   7.76   6.01           5           5   197
#>  4  2013 providence  518.  126.  10.6    3.98          53          54   197
#>  5  2013 washington  410.  110.  10.9    6.88          38          40   197
#>  6  2014 bristol     308.  119.  31.5    7.81           3           3   196
#>  7  2014 kent        534.  135.  16.4    6.77          14          14   196
#>  8  2014 newport     311.  118.   9.13   7.08           6           6   196
#>  9  2014 providence  528.  128.  11.0    3.92          52          52   196
#> 10  2014 washington  406.  111.  10.6    6.66          39          41   196
#> # ℹ 20 more rows