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https://github.com/fbahoken/cartogRaflow

Tips and tricks for flow and movement mapping
https://github.com/fbahoken/cartogRaflow

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Tips and tricks for flow and movement mapping

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README 

        
# Cartograflow 

**Filtering origin-destination Matrices for Thematic Flowmapping**



[![](https://www.r-pkg.org/badges/version/cartograflow)](https://cran.r-project.org/package=cartograflow)

[![](https://cranlogs.r-pkg.org/badges/cartograflow?color=brightgreen)](https://cran.r-project.org/package=cartograflow)



This package is designed to filter origin-destination matrices for flow mapping purposes. It is based on different functions that are mainly used to prepare the flow dataset (pre-processing, filtering ...). It also allows to plot flows in the form of segments and arrows, to map and customize them (compatible `sf` & `cartography`).



# Installation



Installing cartograflow CRAN version:


`install.packages("cartograflow")`



To upgrade to the development version :


See Follow up updates 


`install.packages("devtools")`


`library("devtools")`


`remotes::install_github(url = "https://github.com/fbahoken/cartogRaflow")`



# Follow-up of updates



_**Work in progress**_ : 


Coding of `flowplaces()` and `flowlowup()` for "M" format.


Towards flow filtering for local point of view (major, dominant...). 



[20/07/2020] `cartograflow` CRAN Update to 1.0.3 


Updated functions : `flowtype()`


New function : `flowplace()`, `flowlowup()`



[16/07/2020] `flowlowup()`

`flowlowup()` (currently available for "L" format of matrix),
 is to extracts the upper or the lower triangular part of a matrix.



[05/06/2020] `flowplaces()`


`flowplace()` (currently available for "L" format of matrix),
 is to compute flows margins indicators (on i,j) for places-based flow analysis. 



[02/06/2020] `cartograflow` CRAN Update to 1.0.2  


Suppression of the dependencies in the namespace files gdata and rgdal.

Updated `flowtype()` 



[1.0.0] `cartograflow` initial CRAN version



# Available vignettes 


[\Vignette : rmd and html](https://github.com/fbahoken/cartogRaflow/blob/master/vignettes/) 



[Vignette cartograflow general presentation - CRAN version 1.0.3](http://fbahoken.github.io/cartogRaflow/) 


[subVignette : cartograflow concentration - v. 1.0.2](https://github.com/fbahoken/cartogRaflow/tree/master/vignettes/cartograflow_concentration.html) 


[subVignette : cartograflow distance - v. 1.0.2](https://github.com/fbahoken/cartogRaflow/tree/master/vignettes/cartograflow_distance.html)


[subVignette : cartograflow ordinal distance - v. 1.0.2](https://github.com/fbahoken/cartogRaflow/tree/master/vignettes/cartograflow_ordinal_distance.hmtl) 



# List of functions



## 1. Handling flow data



#### 1.1. Pre-processing



-`flowcarre()` is to transform an un-square to a square matrice from a list of spatial objets ID (code).


-`flowjointure()` is to performs a spatial join between a flow dataset and a map background.


-`flowtabmat()` is to transform a matrice format to a long format and vice versa.


-`flowstructmat()` fixes an unpreviously ID shift in the flow dataset "M" format. If necessary this function is to be used with `flowjointure()` and `flowtabmat`.



#### 1.2. Computing bilateral flows (on Fij)



Check if the matrix is close and square. See `flowcarre()` if not.



-`flowtype()` is to compute the main types of bilateral flows from an asymmetric flow dataset (matrice or long format).


x = "flux" for remaining initial flow _(Fij)_ 


or x = "transpose" for reverse flow value _(Fji)_ 


or x = "bivolum" for bilateral volum as gross flow _(FSij)_=(Fij+Fji) 


or x = "bibal" for bilateral balance as net flow _(FBij)_=(Fij-Fji) 


or x = "biasym" for asymetry of bilateral flow _(FSij)_=(FBij/FSij) 


or x = "bimin" for _(minFij)_=(Fij, Fji) 
 

or x = "bimax" for _(maxFij(Fij, Fji))_ 


or x = "birange" for bilateral _rangeFij_=(maxFij - minFij) 


or x = "bidisym" for bilateral disymetry as _(FDij)_=(rangeFij/FSij).



For x = "bivolum": (or for symetric matrix) 


lowup = "up" for reducing the resulting matrix to the triangular sub-portion above the main diagonal 


lower = "low" for the sub-portion below the main diagonal 



For x = "bibal": (or for antisymetric matrix) 


net = "positive" for extracting the positive flow values 


net = "negative" for extracting the negative flow values.



#### 1.3. Computing flows places oriented indicators (on i or on j) 

`flowplaces()`is to compute flow indicators from the margins of the matrix, e.g. on the flow's places of origin and/or destination.



x = "ini" for the number of incoming links (in-degree)


or x = "outi" for the number of outcoming links (out-degree)


or x = "degi" for the total number of links _ini_=(ini + outi)


or x = "intra" for the total intra zonal interaction (if main diagonal is not empty)


or x = "Oi" for the total flows emitted by (i) place 


or x = "Dj" for the total flows received by (j) place 


or x = "voli" for the total flow volume by place 


or x = "bali" for the net balance by place 


or x = "asyi" for the asymetry of flow by place 


or x = "allflowplaces" for computing all the above indicators.



## 2. Flow analysis



#### 2.1. Concentration



`flowgini()` performs a concentration analysis of a flow dataset - To be use before `flowanalysis()`

Computes _Gini coefficient_ and plot _Lorenz curve_



`flowanalysis()` for computing a flow filter based on _a double criterion for selecting flows_ before mapping.



See : [subVignette : cartograflow concentration](https://github.com/fbahoken/cartogRaflow/blob/master/vignettes/cartograflow_concentration.html) 



#### 2.2. Distance travelled


See : [subVignette : cartograflow distance](https://github.com/fbahoken/cartogRaflow/blob/master/vignettes/cartograflow_distance.html)



You have two ways to consider the distance travelled by flows :

-- if you have a matrice distance, go directly to `flowreduct()` at §2.2.3 ;


-- if not, you can continue here, and have to choose the type of metric (continous or ordinal)



- if you choose the continous metric, you must first join your flows' dataset to a spatial shape, using `flowjointure()`, then use `flowdist()` as described below



**2.2.1. Compute continuous distances matrices**


-`flowjointure()` performs an attribute spatial join - by origin (i) and by destination (j) - between a flow dataset and a spatial shape in order to transfert the origin-destination coordinates (Xi, Yi, Xj, Yj) of the base map to the flow matrice.


`flowdist()` Computes a _continous distance_ matrice choosing metric ("rectilinear", "euclidian", "manhattan") before using  `flowreduct()` to filter the flow dataset.



**2.2.2. Compute ordinal distances matrices** 


See : [subVignette : cartograflow ordinal distance](https://github.com/fbahoken/cartogRaflow/tree/master/vignettes/cartograflow_ordinal_distance.hmtl) 



`flowcontig()` is to compute an _ordinal distance_  matrice based on a k-contiguity matrice.



## 3. Reducing an OD matrice 



**3.1. Reducing by extracting the lower / upper part of a matrix**

`flowlowup()` is to extracts the upper or the lower triangular part of a matrix - preferably for symmetrical matrixes.



x = "up"  for the part above the main diagonal 


x = "low" for the part below the main diagonal.



**3.2. Reducting a flow matrice by an external matrice** 


`flowreduct()` is to reduce the flow dataset regarding another matrix, e.g. distances travelled. 
 



`metric` is the metric of the distance matrix :


- metric= `continuous` (e.g. for kilometers) 


- metric= `ordinal` (e.g. for `k` contiguity) 



If metric = `continuous` (e.g for filtering flows by kilometric distances travelled), use:


`d.criteria` is for selecting the minimum or the maximum distance criteria 


- d.criteria= `dmin` for keeping only flows up to a _dmin_ criterion in km 


- d.criteria= `dmax` for selecting values less than a _dmax_ criterion in km 


`d` is the value of the selected `dmin` or `dmax` criteria.



See : [subVignette : cartograflow distance](https://github.com/fbahoken/cartogRaflow/blob/master/vignettes/cartograflow_distance.html)



## 4. Flow mapping 


`flowmap()` is to plot flows as segments or arrows. Arguments are:


 `filter` is to filter or not flow's information or features 


 `threshold` is used to set the filtering level of the flows when filter="True" 


 `taille` is the value of the width of the flow feature 


 `a.head` is the arrow head parameter 0: no arrow, 1:i->j, 2:i<-j, 3:i<->j. 


 `a.length` is the length of the edges of the arrow head (in inches) 


 `a.angle` is the angle from the shaft of the arrow to the edge of the arrow head 


 `a.col` is the arrow's color 


 `plota` is to add spatial features as map background to the flows's plot 


 `add` is to allow to overlay flow features on external spatial features background 



---

References : this comes after Bahoken, Françoise (2016), _Contribution à la cartographie d'une matrice de flux_, Thèse en Géographie - Siences des territoires, URL : https://halshs.archives-ouvertes.fr/tel-01273776. 



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See also: [Tribute to Tobler(TTT)/Flowmapper](https://github.com/tributetotobler/ttt) - Work in progress