Notes on creating new map databases.

1) See the references:
Richard A. Becker, and Allan R. Wilks,
"Maps in S",
emph{AT\&T Bell Laboratories Statistics Research Report [93.2], 1993.}

Richard A. Becker, and Allan R. Wilks,
"Constructing a Geographical Database",
\emph{AT\&T Bell Laboratories Statistics Research Report [95.2], 1995.}

2) After the .line .gon and .n ascii files have been created or modified,
rerun ./getstats.sh to generate the appropriate .linestats and .gonstats
files.

3) Edit the Makefiles to add the appropriate names to the lists of
.G, .L and .N files

4) Create the ../data/<mapname>.r file consisting of the assignment
'<mapname>MapEnv <- "R_MAP_DATA_DIR"'.  This sets the name of the
environment variable, created at load time (see ../R/zzz.R), that
specifies the location of the binary data files for this collection
of maps. [The mapdata package uses a different environment variable.]

Ray Brownrigg
21 March 2009

NOTES ADDED:

5) Packages like 'maptools' have functionality to read e.g. shapefile data into SpatialPolygon objects. The new function SpatialPolygons2map() can be used as a first step to load such map data from various sources into the maps package. However, the output is similar to that of map(..., fill=TRUE). It does not include polyline information.

6) There is an R package that can ease thet transition from polygon based data to polylines;
https://githib.com:adeckmyn/mapMaker
This package was used to convert the current world and lakes databases from polygons to polylines. Some manual work remains to be done, depending on how clean and consistent the original data is.

Alex Deckmyn
19 Januari 2015