cartograflow (version 1.0.0)

flowreduct: Flow matrice reduction according to another matrix

Description

Reduces a flow dataset according to an external matrix (eg. distance travelled) Computes geographical movements (by weighting a flow dataset according to a distance criterion)

Usage

flowreduct(tab, tab.metric, metric, select, d)

Arguments

tab

is the input flowdata set.

tab.metric

is the table of distance (continuous dataset) or contiguity (ordinal dataset)

metric

See Details.

select

is the continuous distance thresholding parameter. See Details.

d

distance thresholds criterion.

Value

A flow dataset with continuous euclidian distances calculations

Details

-- Metric is 'continous" for distance as euclidian, maximum, manhattan, etc. See flowdist for computing neighbourhood ordinal distance matrix.

select ="dmin" for reducing flow dataset to values that are up or equal to the dmin distance parameter ; select ="dmax" for reducing flow dataset to values that are less or equal to the dmax distance.

-- Metric is 'ordinal' for neighbourhood ordinal distance so-called k contiguity. See flowcontig for computing continuous distance matrix

Examples

# NOT RUN {
library(cartograflow)
data(flowdata)
bkg<- system.file("shape/MGP_TER.shp", package="cartograflow",
                  lib.loc = NULL, mustWork = TRUE)
tab<-flowjointure(flows,bkg,"EPT_NUM")

#Example for reducing a flow matrice with a distance matrice, in long format (i,j, distance)
##1/2: Computes the matrice distances
tab.distance<-flowdist(tab, dist.method = "euclidian",result = "dist")
##2/2: Reduce the flow matrice
tab.flow<-flowreduct(tab,tab.distance, metric = "continous",
                     select = "dmax", #maximum distance travelled criterion
                     d = 8567) #maximum distance value
# }