Here we have the general map types that are used to build the map. Other data sources, such as the OSM reader, have to convert to this format.
Note that this is the most detailed representation of the map. We use this intermediate form, because a Garmin map has (or can have) different levels of zoom which will be at different levels of detail.
So we go through this general representation to construct the actual representations at each level. These actual representations will use objects from the @{link uk.me.parabola.imgfmt.app} package, and they may have a different number of points to this general representation. Indeed they may have different points all together since we may take the average of several points in the general representation