Notes on .ocd format and Mapper compatibility

The .ocd file format for orienteering maps is a proprietary binary format partly documented at .ocad.com web pages. Given its prevalence and long history, Mapper is able to import and export maps in this file format. This page tries to complement the official format documentation, point out its undocumented features, and show where Mapper lacks functionality to support all the features.

Corner points

On plain dashed lines (e.g. ISOM path) or solid lines with mid-symbols (fence), the corner point makes the viewer render full dash/segment length on both sides of the point. However, on dashed lines with mid-symbols (ruined fence), corner points behave like dash points. That is, only half length dash is applied around the point. Yes, it's an undocumented inconsistency.

Dash points

.ocd supports dash points at line ends. That makes the start and/or end dash half in length. It helps to make neat ellipses with the dashed lines like form line. Mapper does not allow dash points on the line ends as of v0.9.5.

Object and area pattern rotation

In .ocd all objects can be rotated, regardless of their symbol's north orientation settings. The symbol north orientation comes into play only during map rotation when objects with the "north orientation" may be excluded from the rotation while the other ones have their pattern and per-object rotation adjusted. Mapper implements the symbol north orientation as zero angle against the north. That is, there is a conceptual difference between Mapper and the .ocd feature. (issue 1926)

Cut circles in point objects

TBA (issue 2003)