Hi Sam
No, a thicker line around the polygon doesn't make the polygon larger (in area). Visually it does seem so but it will not have an effect on the size of the polygon, and it also will not have an effect on a spatial query either.
A thick line around smaller polygons can sometimes make it easier to see this when you zoom out.
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Peter Horsbøll Møller
Principal Presales Consultant | Distinguished Engineer
Precisely | Trust in Data
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