Create a conservation planning problem() following the
mathematical formulations used in Marxan (detailed in Beyer
et al. 2016). Note that these problems are solved using
exact algorithms and not simulated annealing (i.e., the Marxan software).
Usage
marxan_problem(x, ...)
# S3 method for default
marxan_problem(x, ...)
# S3 method for data.frame
marxan_problem(x, spec, puvspr, bound = NULL, blm = 0, symmetric = TRUE, ...)
# S3 method for character
marxan_problem(x, ...)Arguments
- x
characterfile path for a Marxan input file (typically called"input.dat"), ordata.framecontaining planning unit data (typically called"pu.dat"). If the argument toxis adata.frame, then each row corresponds to a different planning unit, and it must have the following columns:- id
integerunique identifier for each planning unit. These identifiers are used in the argument topuvspr.- cost
numericcost of each planning unit.- status
integerindicating if each planning unit should not be locked in the solution (0) or if it should be locked in (2) or locked out (3) of the solution. Although Marxan allows planning units to be selected in the initial solution (using values of 1), these values have no effect here. This column is optional.
- ...
not used.
- spec
data.framecontaining information on the features. The argument tospecmust follow the conventions used by Marxan for the species data file (conventionally called"spec.dat"). Each row corresponds to a different feature and each column corresponds to different information about the features. It must contain the columns listed below. Note that the argument tospecmust contain at least one column named"prop"or"amount"---but not both columns with both of these names---to specify the target for each feature.- id
integerunique identifier for each feature These identifiers are used in the argument topuvspr.- name
charactername for each feature.- prop
numericrelative target for each feature (optional).
'
- amount
numericabsolute target for each feature (optional).
- puvspr
data.framecontaining information on the amount of each feature in each planning unit. The argument topuvsprmust follow the conventions used in the Marxan input data file (conventionally called"puvspr.dat"). It must contain the following columns:- pu
integerplanning unit identifier.- species
integerfeature identifier.- amount
numericamount of the feature in the planning unit.
- bound
NULLobject indicating that no boundary data is required for the conservation planning problem, or adata.framecontaining information on the planning units' boundaries. The argument toboundmust follow the conventions used in the Marxan input data file (conventionally called"bound.dat"). It must contain the following columns:- id1
integerplanning unit identifier.- id2
integerplanning unit identifier.- boundary
numericlength of shared boundary between the planning units identified in the previous two columns.
- blm
numericboundary length modifier. This argument only has an effect when argument toxis adata.frame. The default argument is zero.- symmetric
logicaldoes the boundary data (i.e., argument tobound) describe symmetric relationships between planning units? If the boundary data contain asymmetric connectivity data, this parameter should be set toFALSE. Defaults toTRUE.
Value
A problem() object.
Details
This function is provided as a convenient wrapper for solving Marxan problems using the prioritizr package. Please note that it requires installation of the data.table package to import Marxan data files.
Notes
In previous versions, this function could not accommodate asymmetric connectivity data. It has now been updated to handle asymmetric connectivity data.
References
Ball IR, Possingham HP, and Watts M (2009) Marxan and relatives: Software for spatial conservation prioritisation in Spatial conservation prioritisation: Quantitative methods and computational tools. Eds Moilanen A, Wilson KA, and Possingham HP. Oxford University Press, Oxford, UK.
Beyer HL, Dujardin Y, Watts ME, and Possingham HP (2016) Solving conservation planning problems with integer linear programming. Ecological Modelling, 228: 14--22.
See also
For more information on the correct format for for Marxan input data, see the official Marxan website and Ball et al. (2009).
Examples
# create Marxan problem using Marxan input file
# (note this example requires the data.table package to be installed)
# \dontrun{
input_file <- system.file("extdata/marxan/input.dat", package = "prioritizr")
p1 <-
marxan_problem(input_file) %>%
add_default_solver(verbose = FALSE)
# solve problem
s1 <- solve(p1)
# print solution
head(s1)
#> id cost status xloc yloc locked_in locked_out solution_1
#> 1 3 0.000 0 1116623 -4493479 FALSE FALSE 0
#> 2 30 7527.275 3 1110623 -4496943 FALSE TRUE 0
#> 3 56 37349.075 0 1092623 -4500408 FALSE FALSE 0
#> 4 58 16959.021 0 1116623 -4500408 FALSE FALSE 0
#> 5 84 34220.256 0 1098623 -4503872 FALSE FALSE 0
#> 6 85 178907.584 0 1110623 -4503872 FALSE FALSE 0
# create Marxan problem using data.frames that have been loaded into R
# (note this example also requires the data.table package to be installed)
## load in planning unit data
pu_path <- system.file("extdata/marxan/input/pu.dat", package = "prioritizr")
pu_dat <- data.table::fread(pu_path, data.table = FALSE)
head(pu_dat)
#> id cost status xloc yloc
#> 1 3 0.000 0 1116623 -4493479
#> 2 30 7527.275 3 1110623 -4496943
#> 3 56 37349.075 0 1092623 -4500408
#> 4 58 16959.021 0 1116623 -4500408
#> 5 84 34220.256 0 1098623 -4503872
#> 6 85 178907.584 0 1110623 -4503872
## load in feature data
spec_path <- system.file(
"extdata/marxan/input/spec.dat", package = "prioritizr"
)
spec_dat <- data.table::fread(spec_path, data.table = FALSE)
head(spec_dat)
#> id prop spf name
#> 1 10 0.3 1 bird1
#> 2 11 0.3 1 nvis2
#> 3 12 0.3 1 nvis8
#> 4 13 0.3 1 nvis9
#> 5 14 0.3 1 nvis14
#> 6 15 0.3 1 nvis20
## load in planning unit vs feature data
puvspr_path <- system.file(
"extdata/marxan/input/puvspr.dat", package = "prioritizr"
)
puvspr_dat <- data.table::fread(puvspr_path, data.table = FALSE)
head(puvspr_dat)
#> species pu amount
#> 1 26 56 120.344884
#> 2 26 58 45.167010
#> 3 26 84 68.047375
#> 4 26 85 9.735624
#> 5 26 86 7.803476
#> 6 26 111 478.327417
## load in the boundary data
bound_path <- system.file(
"extdata/marxan/input/bound.dat", package = "prioritizr"
)
bound_dat <- data.table::fread(bound_path, data.table = FALSE)
head(bound_dat)
#> id1 id2 boundary
#> 1 3 3 16000
#> 2 3 30 4000
#> 3 3 58 4000
#> 4 30 30 12000
#> 5 30 58 4000
#> 6 30 85 4000
# create problem without the boundary data
p2 <-
marxan_problem(pu_dat, spec_dat, puvspr_dat) %>%
add_default_solver(verbose = FALSE)
# solve problem
s2 <- solve(p2)
# print solution
head(s2)
#> id cost status xloc yloc locked_in locked_out solution_1
#> 1 3 0.000 0 1116623 -4493479 FALSE FALSE 0
#> 2 30 7527.275 3 1110623 -4496943 FALSE TRUE 0
#> 3 56 37349.075 0 1092623 -4500408 FALSE FALSE 0
#> 4 58 16959.021 0 1116623 -4500408 FALSE FALSE 0
#> 5 84 34220.256 0 1098623 -4503872 FALSE FALSE 0
#> 6 85 178907.584 0 1110623 -4503872 FALSE FALSE 0
# create problem with the boundary data and a boundary length modifier
# set to 5
p3 <-
marxan_problem(pu_dat, spec_dat, puvspr_dat, bound_dat, blm = 5) %>%
add_default_solver(verbose = FALSE)
# solve problem
s3 <- solve(p3)
# print solution
head(s3)
#> id cost status xloc yloc locked_in locked_out solution_1
#> 1 3 0.000 0 1116623 -4493479 FALSE FALSE 0
#> 2 30 7527.275 3 1110623 -4496943 FALSE TRUE 0
#> 3 56 37349.075 0 1092623 -4500408 FALSE FALSE 0
#> 4 58 16959.021 0 1116623 -4500408 FALSE FALSE 0
#> 5 84 34220.256 0 1098623 -4503872 FALSE FALSE 0
#> 6 85 178907.584 0 1110623 -4503872 FALSE FALSE 0
# }