Attribute Override

Attribute overrides define attributes by becoming part of a graphics entity and cannot be changed by changing the attribute table. Entities drawn by MAPPLOT will enable you to specify attribute overrides by defining attributes with the graphics command. To summarize, each graphics entity has associated graphics attributes. These attributes may be specified in an attribute table, or may be specified together with the graphics entity as an attribute override in the plot file.

For example, the following command plots a rectangle using the house attribute table entry, but specifies as attribute overrides; a line style of (3) and a pitch of (0.5):

Attribute overrides remain in effect for all entries that follow until the next command that specifies an attribute name. In the following example, the first rectangle uses house with no overrides, the next two use line style overrides, and the last rectangle again uses house with no overrides:

DATT house,kYt500	\define attribute house
RECT 0,10,5,15,10	\use default attribute house
RECT 0,20,5,25,10,,3,0.5	\use house with style override
RECT 0,30,5,35,10	\override still applies
RECT 0,40,5,45,10,house	\house with no overrides

Attribute overrides may also be applied to line colours, fill colours and thickness by following the attribute name with a colon and the override specification. The following command plots a house with a red outline, but still associates the rectangle with the house attribute:

Colour and thickness overrides will also be passed on to following commands that do not specify an attribute name, in which case they will use the currently active default attribute and overrides.