MapPlot database table for the Earth..4 dataset

This table lists the contents of the MapPlot the Earth..4 dataset. You can access this set of areas by setting mpDataBaseVersion to Ncarg4_1 (alias: MediumRes) and mpDataSetName to Earth..4. This dataset was introduced in 2008. It is much like "Earth..2", but has about 10 times as much detail and is much more accurate. Its coastlines are simplified versions of those in the RANGS database and its political outlines match what one finds on a web site such as Wikimapia. In addition to the provinces of Canada, the states of Mexico, and the states and counties of the conterminus United States, it provides the state/province outlines of Australia, Brazil, China, and India. The ice shelves of Antarctica are included as separate entities, that can be made to appear or not, as desired.

Like all datasets that use the Ncarg4_1 database version, each named area has a position in a hierarchical tree. At the top level there are only two areas: "Land" and "Water." All other areas are descendents of these areas. The Earth..4 dataset has four levels below level 1, the top level. Level 2 is the contenental level, level 3 the national level, and level 4 contains state and provincial boundaries. Level 5 contains counties of the conterminous US. There are no county boundaries for Alaska and Hawaii in the dataset. The level associated with each area name can be retrieved by getting the value of the array resource mpAreaTypes. Each element of this resource corresponds element by element to the array resource mpAreaNames, which contains the names of each area.

Each area has a basic name and also has a fully qualified name derived by determining its ancestor chain up to the top level. You can retrieve an array containing the basic area names by getting the value of the resource mpAreaNames. However, not all the basic area names are unique, and in these cases the name returned by mpAreaNames contains enough additional elements of the fully qualified name to uniquely identify the name. There are, for example, four islands in the dataset called "Bird Island." In order to provide a name that will uniquely identify the area in these cases, MapPlot prefixes the name with the immediate parent. If the parent is at a higher level (lower value of mpAreaTypes), then a colon character (':') is placed between the names. If the parent is at the same level, a period character ('.') is used instead. The name strings as returned in the mpAreaNames are sufficient to provide valid unique names for the specifier resources such as mpFillAreaSpecifiers. If a non-unique basic name (such as "Bird Island") is supplied to a specifier resource, all matching areas will be added to the specifier list.

In the table below the last column contains the fully qualified the area names. The basic name, qualified sufficiently to be unique, is in bold type. The bolded part of the name is what is returned by the mpAreaNames array. The index of each area in the array is given in the first column of the table, labelled "Element Index."

The second column, labelled "Type", contains the level assigned to each area as returned by getting the value of the array resource mpAreaTypes.

The third column, labelled "Fixed Group" contains the fixed area group number assigned to each area. This value is used to determine the "geophysical" fill coloring of each area. Since it is based only on whether an area is ocean, land, or inland water, it cannot be modified by the user. You can access these values by getting the array resource mpFixedAreaGroups.

The fourth column, labelled "Dynamic Group", contains the dynamic area group number assigned by default to each area. This group is used to determine the "political" fill coloring assigned to each area in the database. The default 10 values are arranged such that distinct adjoining areas will be different colors. However, the user can change the number of groups and change any area's group number for other purposes, such as to represent statistical data. You can access these values through the array resource mpDynamicAreaGroups.