shx - the shape index format - stores the indexes of shapes for fast searching shp - the shape format - stores the actual geometric shapes (points, lines, polygons) Technically a shapefile comprises of several files: The most popular format is the open specification shapefile vector - representing features such as points, lines and polygons.ArcGIS operates on data of two broad types: The Environmental Systems Research Institute (ESRI) is the producer of GIS (Geographic Information System)Īnd geodatabase management applications (notably ArcGIS). MagIsl <- maps ::: map.poly ( "worldHires", "Australia:Magnetic Island", exact = FALSE, xlim = c ( 110, 160 ), ylim = c ( - 45, - 5 ), boundary = FALSE, interior = TRUE, fill = TRUE, as.polygon = TRUE ) magIsl.sp <- map2SpatialPolygons (magIsl) par ( mar = c ( 0, 0, 0, 0 ), xaxs = "i", yaxs = "i" ) plot (magIsl.sp, col = "grey" ) High resolution versions of these databases are provided by an additional package ( mapdata) and compatible routines to convertīetween different mapping projections are provided by the mapproj package. The data are stored and accessed via a simple database. The maps package contains world mapping data as well as routines for displaying maps of countries, regions etc. Sources and routines are equally appropriate for other regions. Note that the focus here is very Australia (and Queensland) centric. The following subsections describe some of the useful sources of spatial data.
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