The Visibility properties panel for the entire symbol or symbol layers is identical to the Visibility panel in the 'Layer Properties' dialog box.

The Minimum and Maximum Scale boxes allow the user to specify an exact scale at which the selected component will be visibile. Defining a Minimum scale means that a symbol or layer will not appear below that particular setting, and likewise for the Maximum scale setting. If no threshold values are defined the selected symbol or layer is visible at all scales by default. Each component can have a defined Min/Max scale, for example a Point layer of a symbol could have a defined visibility scale of 0 - 20 000, whereas the symbol and entire layer have no thresholds specified. This would mean that the entire symbol and layer are visible at all scales, however the Point (label) layer only appears when the map is zoomed in to a scale of 20 000. Using this feature can reduce clutter on the map and provide details when specific features are being examined up close.

Transparency can also be set for the entire symbol or individual layers of the symbol. This could be a useful tool if the Fill portion of the symbol needed to be somewhat transparent but the Point (Label) needed to be written in solid opaque paint to be easier to read and identify. By selecting 'Transparent Paint' for the the Fill symbol and adjusting the transparency setting (0 = clear 100 = solid), other layers could be seen beneath this symbol, however 'Opaque Paint' could be chosen for the Point symbol so that it appear in solid paint and nothing can be seen beneath it.


Remember that the transparency settings are cumulative and therefore multiplied together as the map is drawn. If transparent paint was set at 50% for the Fill of a symbol and the entire symbol was set to 50% (so it appeared more transparent than other symbols in the layer) AND the layer itself was set to 50%, the original Fill of the modified symbol would be barely visible at only 12.5%!

Erasing paint is available in the symbol editor as well, and may be useful in certain situations. Erasing paint is used for symbols that represent dynamic information derived from the model. For example, the symbol that represents a Clear Cut treatment type may be drawn in certain blocks all over the planning area while the optimization model is attempting to find the best solution to the problem. If normal paint is used to draw this CC symbol, the entire planning area will eventually appear clear cut! If however an unclassified symbol is designed with erasing paint, previous CC blocks will disappear as the model places a CC in another block. These types of themes require further customization and are discussed in the section called “The PIN file”.