EtrsDasymetricSurface: The DasymetricSurface class

In etsakl/DasyMapR: Geographical ETRS-LAEA Grid Based Dasymetric Mapping

Description

The DasyemetricSurface class holds the basic information for dasymetric surface represanation in ETRS-LAEA grid form

P_mu = (R_A x P_A ) x N / E P_cell = (R_A x P_A /P_A ) x (N / A_T ) / E = (R_A x N / A_T ) / E Where, P_cell is the population of a cell, R_A is the relative density of a cell with land-cover type A, P_A is the proportion of cells of land-cover type A in the enumeration unit. N is the actual population of enumeration unit (i.e., census block B group) E is the expected population of enumeration unit calculated using the relative densities. A_T is the total number of cells in the enumeration unit. P_A / P_A cancels P_A out of the equation, i.e., not used in the cell- based method.

Usage

EtrsDasymetricSurface(input.surface.grided, ancillary.grided, ...)

EtrsDasymetricSurface(input.surface.grided, ancillary.grided, ...)

Arguments

ancillary.grided

Value

An DasymetricSurface Object

EtrsDasymetricSurface

Slots

SpatialPolygonsDataFrame.

the input surface plus new data columns

over.method.type

character. MaxArea for categorical data PropCal for numeric #'values

cell.size

numeric. Indexing the column of data frame that contains the value of #'interest

CELLVALUE

character. The size of the cell (the new map unit)

Examples

# test Dasymetric  -------------------------------------------------------
# Make a spatial polygon
S<-readWKT("POLYGON((0 0,2000 0,2000 2000,0 2000,0 0))",id = "S",p4s = CRS("+init=epsg:3035"))
df<-cbind(AREA=gArea(S),VALUE=1000)
row.names(df)<-sapply(slot(S,"polygons"),function(x) slot(x,"ID"))
df<-as.data.frame(df)
S<-SpatialPolygonsDataFrame(S,data = df,match.ID = TRUE)
# Covert actuall value to density
S<-ActuallVal2Density(input.surface = S,surface.value.col = 2,area.unit = 1e+06)
# plot
X11(width=12,height = 12)
split.screen(figs = c(3,2))
screen(1)
plot(S)
title("the input surface")
text(coordinates(S)[,1],coordinates(S)[,2],S[["VALUE"]])
text(coordinates(S)[,1],coordinates(S)[,2],S[["VALUE"]])
#grided
S.grided <- etrsSourceSurface(input.surface = S,over.method.type = "PropCal",surface.value.col = 2,cell.size = 500)
screen(2)
plot(S.grided)
title("... Projected to ETRS-LAEA 500 m")
text(coordinates(S.grided)[,1],coordinates(S.grided)[,2],S.grided[["CELLVALUE"]])

#the ancillary surface
A<-readWKT("POLYGON((0 0,1000 0,1000 500,0 500,0 0))",id="A" ,p4s = CRS("+init=epsg:3035" ))
df<-cbind(AREA=gArea(A),RelDens=1)
row.names(df)<-sapply(slot(A,"polygons"),function(x) slot(x,"ID"))
df<-as.data.frame(df)
A<-SpatialPolygonsDataFrame(A,data = df,match.ID = TRUE)
screen(3)
plot(S,border="lightgrey")
plot(A,add=T)
title("the ancillary surface")
text(coordinates(A)[,1],coordinates(A)[,2],A[["RelDens"]])
#grided
A.grided <- etrsAncillarySurface(input.surface = A,over.method.type = "PropCal",surface.value.col = 2,cell.size = 500,binary = FALSE)
screen(4)
plot(S.grided,border="lightgrey")
plot(A.grided,add=T)
title("... Projected to ETRS-LAEA 500 m")
text(coordinates(A.grided)[,1],coordinates(A.grided)[,2],A.grided[["WCELLWEIGHT"]])
#EtrsDasymetric
screen(6)
D.grided<-EtrsDasymetricSurface(input.surface.grided = S.grided,ancillary.grided = A.grided,actuall.value = TRUE)
plot(S.grided, border = "lightgrey")
plot(D.grided,add=T)
title("Finally the Dasymetric Surface")
text(coordinates(D.grided)[,1],coordinates(D.grided)[,2],D.grided[["DASYCELL"]])

etsakl/DasyMapR documentation built on May 16, 2019, 9:07 a.m.