About Performing the Squaring of Traced Outlines
When extracting appropriate objects such as buildings, the traced outlines
may be squared using an orthogonal squaring algorithm. The extent
of the squaring is determined by the squaring angle.
Learn
how to modify the squaring angle
When squaring is performed, additional
attributes
are stored for the extracted outlines. The attributes that are fit
metrics (i.e., goodness of fit) that estimate how well the squared
outlines fit around the traced points. The goodness of fit is based
on the distances (i.e., the errors) between each point of the traced
outline and the corresponding side of the squared outline. The error
is calculated perpendicular to the side of the squared boundary, except
for the corner points of the squared boundary. In the case of the
corner points, the error is the distance between the corner and the
corresponding point of the traced boundary. The following is a brief
discussion of each fit metric:
- RmsError: calculated by squaring
each error and then taking the square root of the average of the
squares.
- MaxErr: the maximum of the absolute
value of the errors
- ForceFit: this is 0 and 1 value.
Values of 1 indicates squared outlines that have poor fits, and
can be considered of high priority for QA.
Higher values of each fit metric would indicate poorer fits.
