WorldMap

DESCRIPTION

The WorldMap module reads a compressed version of the "CIA World Data Bank II map database" and produces a two-layer pyramid which contains a cropped, decimated map, in units of degrees longitude and degrees latitude, containing only those features selected by the user.

INPUTS

WIDGETS

Port: CIA Map Directory
Type: Text
The CIA Map Directory parameter should be set to the directory in which the CIA and plate boundary maps may be found. The CIA maps are available by anonymous ftp from hanauma.stanford.edu (36.51.0.16). The compressed version found there will untar into a map directory with subdirectories named africa.Map, asia.Map, europe.Map, namer.Map, and samer.Map. The original database (not the compressed version used here) is available from the U.S. Government and is in the public domain. The USGS_plates.txt file included with this module should be added to the map directory if you need plate boundary maps. The maps consume about 13 megabytes of disk space.

Port: International
Type: Option Menu
Menu Item: None
Menu Item: Definite
Menu Item: Indefinite
Menu Item: Other
The International and National menus refer to political boundaries.

Port: Coasts, Islands, and Lakes
Type: Option Menu
Menu Item: None
Menu Item: Major
Menu Item: Additional Major
Menu Item: Intermediate
Menu Item: Minor
Menu Item: Intermittent Major
Menu Item: Intermittent Minor

Port: Reefs, etc.
Type: Option Menu
Menu Item: None
Menu Item: Reefs
Menu Item: Salt Pans
Menu Item: Both

Port: Ice
Type: Option Menu
Menu Item: None
Menu Item: Glaciers
Menu Item: Shelves
Menu Item: Both

Port: Parallels
Type: Option Menu
Menu Item: None
Menu Item: Equator
Menu Item: Tropics
Menu Item: Every 20
Menu Item: Every 10
Menu Item: Every 5
Menu Item: Every 1
The Parallels and Meridians menus place grid lines on the map, spaced as indicated. The lines consist of 1 degree segments and will therefore curve when used with the Projector module.

Port: Meridians
Type: Option Menu
Menu Item: None
Menu Item: Prime
Menu Item: Every 90
Menu Item: Every 45
Menu Item: Every 20
Menu Item: Every 10
Menu Item: Every 5
Menu Item: Every 1
The Parallels and Meridians menus place grid lines on the map, spaced as indicated. The lines consist of 1 degree segments and will therefore curve when used with the Projector module.

Port: Rivers
Type: Option Menu
Menu Item: None
Menu Item: Permanent Major
Menu Item: Additional Major
Menu Item: Additional
Menu Item: Minor
Menu Item: Double Lined
Menu Item: Intermittent Major
Menu Item: Intermittent Additional
Menu Item: Intermittent Minor

Port: Canals
Type: Option Menu
Menu Item: None
Menu Item: Major
Menu Item: Lesser
Menu Item: Irrigation

Port: Precision
Type: Text
The Precision parameter should be set to the size, in seconds, of the largest feature which the decimation routine will eliminate. Usually this should be no higher that 3600 seconds (1 degree). A setting of 1 second will include all features since raw map coordinates are in integer numbers of seconds. Most features on the map appear to be on the order of thirty seconds. The decimation algorithm operates by combining as many line segments smaller than precision as possible such that their total vector length is still less than Precision into a single line segment. This will tend to eliminate features smaller than Precision and small islands may be reduced to a segment of zero length.

Port: Min Longitude
Type: Text
The Min/Max Latitude/Longitude parameters control the region of the earth to be mapped and are in degrees. Latitudes may take on any value as long as Min < Max and they span no more than 360 degrees.

Port: Max Longitude
Type: Text
The Min/Max Latitude/Longitude parameters control the region of the earth to be mapped and are in degrees. Latitudes may take on any value as long as Min < Max and they span no more than 360 degrees.

Port: Min Latitude
Type: Text
The Min/Max Latitude/Longitude parameters control the region of the earth to be mapped and are in degrees. Latitudes may take on any value as long as Min < Max and they span no more than 360 degrees.

Port: Max Latitude
Type: Text
The Min/Max Latitude/Longitude parameters control the region of the earth to be mapped and are in degrees. Latitudes may take on any value as long as Min < Max and they span no more than 360 degrees.

Port: National
Type: Option Menu
Menu Item: None
Menu Item: Definite
Menu Item: Indefinite
Menu Item: Other
The International and National menus refer to political boundaries. National boundaries only exist for the U.S. states and Canadian provinces.

Port: Plates
Type: Option Menu
Menu Item: None
Menu Item: All

OUTPUTS

Port: Output
Type: Pyramid
Constraints: n-layer.
optional-baseLat.
n-D compression.
n-compression type.
The output pyramid follows the finite element convention and is suitable for feeding into PyrToGeom. The coordinates are curvilinear and of the form (longitude, latitude, 0.0). There is a single data variable which is set to a number from 0 to 99 depending on the particular feature that is represented. When a colormap is used with PyrToGeom, this data allows each feature to have different color. Map Feature Color Numbers The pyramids produced by the WorldMap module have data in the base lattice which is meant for use with a colormap. Below is a table of these color-numbers and their associated features.

1 Demarcated or delimited international boundary

2 Indefinite or in dispute international boundary

3 Other line of separation of sovereignty on land

21 Demarcated or delimited national boundary

22 Indefinite or in dispute national boundary

23 Other national boundary

41 Coasts, islands and lakes that appear on all maps

42 Additional major islands and lakes

43 Intermediate islands and lakes

44 Minor islands and lakes

46 Intermittent major lakes

47 Intermittent minor lakes

48 Reefs

49 Salt pans-major

50 Salt pans-minor

53 Ice shelves-major

54 Ice shelves-minor

55 Glaciers

61 Permanent major rivers

62 Additional major rivers

63 Additional rivers

64 Minor rivers

65 Double lined rivers

66 Intermittent rivers-major

67 Intermittent rivers-additional

68 Intermittent rivers-minor

70 Major canals

71 Canals of lesser importance

72 Canals-irrigation type

81 Plate boundaries

99 Grid lines / BendBox output

PROBLEMS

Remember that the map files are greatly compressed and when read into memory the map will be much larger. It is best to start at lower resolution with fewer features and build up than to attempt to read in the entire map at full resolution. One must use less resolution when looking at large areas and higher resolution when zooming in. This will also improve the drawing time for the map.

Boundaries which are also coastlines or rivers are not included in the boundary files. Thus, in order to see the outline of Minnesota, it is necessary to turn on Major Coastlines, Major Rivers, Definite International, and Definite National. Most of the option menus (see exceptions below) operate on the principle that if you want, for example, Minor Rivers, you also want Major Rivers. Therefore selecting a feature on an option menu implies selecting all features above it on the menu as well. Of course some options, such as Plates, are simply all or none. The Reefs, etc. and Ice menus are the exception to the above. Due to the limited number of input ports allowed by explorer, it was necessary to combine features in these menus. Thus the options are none, one, the other, or both.

SEE ALSO


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© The Numerical Algorithms Group Ltd, Oxford UK. 1996