read.coverage: Function for retrieving basic data from a given coverage

In RArcInfo: Functions to import data from Arc/Info V7.x binary coverages

Description

This function allows the user to retrieve the main data stored in the chosen coverage. This doesn't mean that all the data are retrieved, but only the most important.

Tables are not imported, but a dataframe containig the information provided by a call to get.tablenames of all the tables related to the coverage.

For a single coverage there can be more than one pal file, so just their names are imported (into 'palfiles'). Then, the user can choose which one to import by calling get.paldata. But, if there is just one pal file, it is imported into 'pal'.

The names of the different files are supposed to be the default names when calling the proper get.XXXdata. If some of these names change then the function will not import that feature properly. But this fact should never happen.

Usage

read.coverage(datadir, coverage)

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

Value

This function returns a list of all the data directory, coverage name and all the data imported: i

datadir	The directory where all the coverages are stored, the one used when this function was called.
coverage	The name of the coverage used when calling this function.
arc	The arc definitions, as returned by get.arcdata.
bnd	The bounday definition, as returned by get.bnddata.
cnt	The polygon centroids, as returned by get.cntdata.
lab	The label point records of the coverage.
pal	If there is just one file for the polygon definitions inside the coverage, it is imported here using get.paldata. Otherwise, it is filled with a 'NULL'.
palfiles	The names of all the polygon definitions files.
tblnames	The description of all the tables related to the coverage, as returned by get.tablenames.
tol	The tolerance values.

References

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

RArcInfo documentation built on May 1, 2019, 10:26 p.m.