flowcontig {cartograflow} | R Documentation |

## Builds an ordinal distance matrices from a spatial features background

### Description

From a layer of areal spatial features, compute an ordinal distance matrice
based on a k order criterion of adjacency or contiguity between origin and destination places .

The result is a neighbourhood graph that can be used for filtering flow values before flow mapping (flowmap)

### Usage

```
flowcontig(bkg, code, k, algo)
```

### Arguments

`bkg` |
a layer of areal spatial features (eg. the map background) |

`code` |
spatial areal features code |

`k` |
order of adjacency or contiguity between two areal spatial features |

`algo` |
algorithm to use for ordinal distance calculation. Default is "Dijkstra's" algorithm. See Details. |

### Details

The (k=1,2,...,k) order of adjacency or contiguity, of an areal spatial features
background, is the number of spatial boundaries to be crossed between
a couple of origin-destination (ODs) places. The k number can be assimilated to a shortest path between two pair of nodes
Argument 'k' is to enter the number k of the contiguity matrix to be constructed ;

-ordre=1 : ODs places are adjacent, ie the flow have to cross only 1 boundary

-ordre=2 : ODs places are distant from 2 borders

-ordre=k : ODs places are distant from k borders

The function returns also the (k) number of the layer

### Value

a contiguity matrice with the k orders of adjacency

### Examples

```
library(cartograflow)
library(sf)
data(flowdata)
map <- st_read(system.file("shape/MGP_TER.shp", package = "cartograflow"))
graph_ckij_1 <- flowcontig(bkg = map, code = "EPT_NUM", k = 1, algo = "automatic")
flowmap(
tab = graph_ckij_1,
fij = "ordre", origin.f = "i", destination.f = "j",
bkg = map, code = "EPT_NUM", nodes.X = "X", nodes.Y = "Y",
filter = FALSE
)
```

*cartograflow*version 1.0.5 Index]