filterUnits

The filterUnits attribute defines the coordinate system for the attributes x, y, width and height.

Only one element is using this attribute: <filter>

Value	userSpaceOnUse | objectBoundingBox
Default value	objectBoundingBox
Animatable	Yes

userSpaceOnUse

x, y, width and height represent values in the current coordinate system that results from taking the current user coordinate system in place at the time when the <filter> element is referenced (i.e., the user coordinate system for the element referencing the <filter> element via a filter attribute).

objectBoundingBox

In that case, x, y, width and height represent fractions or percentages of the bounding box on the referencing element.