The following clauses affect the coordinate system of the map and distance type in use.
Syntax
Set Map
[ Window window_id ]
[ CoordSys... ]
[ Distance Type { Spherical | Cartesian } ]
[ XY Units xy_unit [
{ Display Decimal {On | Off } |
Display Grid [ { MGRS | USNG [ Datum datumid ] } ]
}
] ] window_id is the integer window identifier of a Map window.
xy_unit is a string representing the name of an x/y coordinate unit (for example, "m" for meters, "degree" for degrees). If the XY Units are in degrees, the Display Decimal clause specifies whether to display in decimal degrees. Set to On to display in decimal degrees or Off to set in degrees, minutes, or seconds. Set Display Grid to display in Military grid reference format.
datumid is a numeric expression representing the datum id. It must evaluate to one of the following values:
DATUMID_NAD27 (62)
DATUMID_NAD83 (74)
DATUMID_WGS84 (104)Description
CoordSys clause Assigns the Map window a different coordinate system and projection. For details on the syntax of a CoordSys clause, see CoordSys clause.
The MapBasic coordinate system must be set explicitly with a Set CoordSys statement and can be retrieved with the SessionInfo( ) function.
This example only alters the map's coordinate system and units; the MapBasic coordinate system is unaffected:
Set Map XY Units "m" CoordSys Earth Projection 8,
33, "m", -55.5, 0, 0.9999, 304800, 0 Distance Type is either Spherical or Cartesian. All distance, length, perimeter, and area calculations for objects contained in the Map window will be performed using one of these calculation methods. Note that if the coordinate system of the Map window is NonEarth, then the calculations will be performed using Cartesian methods regardless of the option chosen, and if the coordinate system of the Map window is Latitude/Longitude, then calculations will be performed using Spherical methods regardless of the option chosen.
XY Units specifies the type of coordinate unit used to display x-, y-coordinates (for example, when the user has specified that the map should display the cursor position on the status bar). The unit name can be "degree" (for degrees longitude/latitude) or a distance unit such as "m" for meters.
If the XY Units are in degrees, the Display Decimal clause specifies whether to display in decimal degrees (On) or in degrees, minutes, seconds (Off). Display Grid will display coordinates in Military Grid reference system format no matter how the XY Units are specified.
Set Map XY Units "m" Display Grid
Set Map XY Units "degree" Display Grid
Set Map XY Units "degree" Display Decimal On
Set Map XY Units "degree" Display Decimal Off The following statement specifies meters as the coordinate unit:
Set Map XY Units "m"