These classes are based on the Shapefile Specifications
listed in the ESRI (Environmental Systems Research Institute) document: ESRI
Shapefile Technical Specifications - An ESRI White Paper - July 1998.
The
Shapefile format is the exchange format for vector maps of
the ESRI. This format supports polygons, arcs, lines, and points.
Each Shapefile contains one single theme, meaning that all the objects
in the file are of the same type (either line, point, polygon, or
another type of object). In the Shapefile format, a theme is essentially
described with four different files:
A shapefile (.shp
)
contains the geometry of the objects.
A Dbase file (.dbf
)
contains the attributes of the objects.
An index file (.shx)
contains
the index and sizes of the objects of the .shp
file.
A spatial index file (
.idx
)
contains tiling information. This file is
JViews Maps package specific, and is used to
perform
load-on-demand on Shapefiles.
This format does not contain information concerning the
coordinate system used to reference the position of the graphic objects.
Objects in Shapefiles are often positioned within a geographic coordinate
system (
IlvGeographicCoordinateSystem), but this is far from being the rule.
The Shapefile format comprises the following classes: