Discussion: OCAD Map w/ Photo Backgound

Last night our little informal training group navigated on a new map of a local park. The mapper threw together an OCAD map using LIDAR coutours and aerial photos as the base. The map was brilliant for this sort of informal training in a new area. The map was printed with the aerial photo in the background and OCAD map and course symbols in the foregound. The obvious weekness of the technique is that some symbols were difficult to read against the background of the aerial photo.

It would be nice to have a set of OCAD symbols that are optimized to contrast well with aerial photos. For example, the contour symbol would be vastly more readable if it simply had a had a thin white border on either side of the brown line. Same goes for the Control symbol.

Perhaps those kind of photo-optimized symbols are already available? Or is it possible to modify the properties of the existing symbols? Or perhaps substituting a road symbol for a contour line? Can the road symbol be reduced in size to match the width of a contour line? Can the border color of the road be changed from black to white?

In OCAD you can modify symbols, create new symbols, create new colours and apply them to symbols. You can add a frame to symbols, eg a white border.

I did this for the Orienteering Marathon (42.2km) held in Valley Forge, PA last December. I found that whitening the background (mixing with, say 50% white, so that the darkest black in the original photo becomes a medium gray) worked pretty well for the OCAD-overlay-on-photo parts of the map.

I lightened ("dimmed" in OCAD parlance) the templates 20% and that seemed to work decently on midtone areas. However, the park had some pine plantations which showed up a very dark green and were probably still too dark, in retrospect. Going to 40% dimming and perhaps scaling up the contour symbols a little might have made a great improvement, as long as it didn't wash out any of the lighter areas.