| Package: |
| GeoXp |
| Type: |
| Package |
| Version: |
| 1.6.1 |
| Date: |
| 2012-09-07 |
| License: |
| GPL Vesion 2 or later |
In the version 1.5.0, GeoXp has adopted the SpatialClass object proposed by Roger Bivand
in sp package. The main advantage of using this structure object is on one hand,
a SpatialClass object can contain both spatial coordinates and a data.frame
of observed variable and on an other hand, it offers the possibility to make spatial analysis using both
packages derived from sp as spdep, gstat and GeoXp.
On the map, the coordinates of sites are represented by
using the function coordinates included in sp package, which calculates
longitude (for x-axis) and latitude (for y-axis), applied on a Spatial Class Object.
In GeoXp, we can find three main groups of functions:
- functions using only one variable: the interest variable
is designed by argument name.var, a character corresponding to a column of the data.frame
included in sp.obj, i.e. the Spatial Class object. It can be a numeric variable (histomap(),
densitymap(), angleplotmap...) or a factor variable (or character) (barmap(),...).
- functions using both several variables: the variables of interest are designed by argument
names.var, a vector of character corresponding to columns of the data.frame
included in sp.obj. It can be two numeric variables (dblehistomap, dbledensitymap),
one numeric variable and one factor (histobarmap(), polyboxplotmap()),
several numeric variables (plot3dmap, pcamap() and clustermap()).
- functions using both a variable and a spatial weight matrix created as a nb or listw object
(see package spdep).
In the case where sp.obj is a SpatialPolygonDataFrame, user will have the opportunity to draw
the polygons of Spatial unit by using the Draw Saptial contours button in the Tk window. User can
also give a spatial polygonal contour as background map with option carte: in this case,
a spatial polygonal contour is a matrix of numeric values with 2 columns (x and y coordinates of
the vertices of the polygons) where polygons are seperated from each other
by 3 rows of NaN. The functions (polylist2list() and spdf2list())
convert some spatial objects (Polylist and SpatialPolygonDataFrame)
into matrix as decribed above to draw a background map.
Among options which are common to each function, users have the
possibility to give a criteria, vector of boolean of size the number of Spatial units,
with TRUE on specific sites. These sites are then represented by a green croice on the map
by clicking on preselected sites button on the Tk window.
Moreover, users have the possibility to make bubbles and add some graphs
(histogram, barplot or scattermap). The potential variables are included
in the data.frame of the SpatialObject. Users can choose a proportional
symbol mapping: in function plot, we give value
$sqrt(var)$. User can choose if a legend has to appear on
the map. He could choose then three values represented by bubbles of
corresponding sizes.
Finally, users can choose to represent the graphical with different colors
using argument col. In the case of factors (as function barmap), users could choose
if a legend with corresponding colors will appear on the map. Users can also modify the representation of
selected sites on map with argument pch.
Recent functions barnbmap and histnbmap give the opportunity to analyse spatial
weight matrix build using functions included in spdep package.
Roger S.Bivand, Edzer J.Pebesma, Virgilio Gomez-Rubio (2009), Applied Spatial Data Analysis with R, Springer.