Symbol Scales

All Symbol objects are defined in Named Object Libraries using paper units.

This means the objects contain information about paper print size; their size on screen must be recalculated each time they are drawn.

  • When you create a Symbol the current viewing scale is used to convert the items from world units into paper units.
  • When you place Point items which use that particular symbol, the Point item’s dataset scale is used to convert from paper units back to world units.
  • The net result is that the placed Symbol objects appear the same size as the original graphics unless the dataset scale is different to the original view scale.

You can modify the size of a Symbol by setting the Scale property which has a default value of 1 (one).

When the effective viewing scale is the same as the dataset scale, a negatively scaled Symbol will appear the same as a positively scaled Symbol (so -2.5 would be the same as +2.5).

By default SIS Desktop 9 assumes you will print the current SIS Workspace Definition (SWD) on paper at the current viewing scale. So it shows you how big the Symbol objects are relative to other graphics (like roads and buildings). Related Topics Link IconRelated Topics

However some applications are more interested in how the graphics appear on screen than on how they will appear on paper. (e.g. a Command and Control system where moving objects like cars are tracked on screen).

In this case you can use a negative Scale. A Scale of -1 will cause the Symbol to be drawn at its Named Object Library size on screen regardless of how much you zoom in or out.