RArcInfo (version 0.3)

get.arcdata: Function for importing the contents of an ARC file into R

Description

This function reads and imports into R the contents of an arcs definition file.

Usage

get.arcdata(datadir, coverage, filename="arc.adf")

Arguments

datadir

Directory under which all the coverages and a directory called 'info' are.

coverage

The name of the coverage we want to work with.

filename

The name of the file in the coverage directory that stores the data. By default, it is called 'arc.dat'.

Value

• This function returns a list with two elements. The first one is a data frame containing the next fields (by columns):
• ArcID
  A number that identifies this arc.
• ArcUserID
  Identifier defined by the user.
• FromNode
  The node where the arc begins.
• ToNode
  The node where the arc finishes.
• LeftPoly
  The number of the polygon that is to the left of the arc.
• RightPoly
  The number of the polygon that is to the right of the arc.
• NVertices
  The number of vertices the arc has.
• The second element is a list that stores the vertices of the arc. So, each element in this list is also a list of two arrays: the first for the X coordinates and the secod for the Y coordinates.

References

More information about this kind of data can be found at http://pages.infinit.net/danmo/e00/docs/v7_bin_cover.html.