ArcGIS Developer Help

ITemplate Interface

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

ITemplate is the pattern of marks and gaps that are used to draw a line symbol. A mark and gap together are refered to as a pattern element. The pattern element is drawn based on the value of the mark and gap, which is specified in points (approx 1/72 inch). The mark is something that is drawn, hence it can be a marker symbol in a IMarkerLineSymbol, a hash in a IHashLineSymbol, or a dash in a ICartographicLineSymbol.

The width of the mark is arbitrary, in that you must specify it (in previous versions of ArcGIS for Desktop Advanced [ArcInfo] and ArcGIS for Desktop Basic [ArcView], the width of the mark and gap were the same size, and based on the width of the element that was being repeated within the template).

The mark that is drawn in the template (marker, hash, or dash) will be centered on the mark. Thus, if you have a marker symbol that is size 10, you would likely specify a mark value of 10. Then if you want no gap between the markers, specify the gap to be 0 (zero). But if you wanted a space of 20 points between each marker, then you'd specify the gap to be 20.

If you don't want the mark to be the first element in the line, then you need to use at least two pattern elements. The first one would start with a mark of 0 (zero), which indicates that no mark is to be drawn, and then a gap that matches the distance you want to inset the mark along the line.