Purpose
Returns the area as calculated in a flat, projected coordinate system using a Cartesian algorithm. You can call this function from the MapBasic window in MapInfo Pro.
Syntax
CartesianArea( obj_expr, unit_name )obj_expr is an object expression.
unit_name is a string representing the name of an area unit (e.g., "sq km").
Return Value
Float
Description
The CartesianArea() function returns the Cartesian area of the geographical object specified by obj_expr.
The function returns the area measurement in the units specified by the unit_name parameter; for example, to obtain an area in acres, specify "acre" as the unit_name parameter. See the Set Area Units statement for the list of available unit names.
The CartesianArea() function will always return the area using a cartesian algorithm. A value of -1 will be returned for data that is in a Latitude/Longitude since the data is not projected.
Only regions, ellipses, rectangles, and rounded rectangles have any area. By definition, the CartesianArea() of a point, arc, text, line, or polyline object is zero. The CartesianArea() function returns approximate results when used on rounded rectangles. MapBasic calculates the area of a rounded rectangle as if the object were a conventional rectangle.
Examples
The following example shows how the CartesianArea() function can calculate the area of a single geographic object. Note that the expression tablename.obj (as in states.obj) represents the geographical object of the current row in the specified table.
Dim f_sq_miles As Float
Open Table "counties"
Fetch First From counties
f_sq_miles = CartesianArea(counties.obj, "sq mi")You can also use the CartesianArea() function within the Select statement, as shown in the following example.
Select lakes, CartesianArea(obj, "sq km")
From lakes Into results See Also: