Plotting Board

[cletrac (RIP)]

I got this plotting board off ebay and was wondering what all the built in pouches held. The full length one on the small flap must be for a ruler, and the two shorter ones beside it would be for dividers. The pencil holders are obvious but any help on the rest of them?
There's a full size flap on the right half that would have protected extra maps. On the face of the map board there are depressions with large headed screws for attaching maps.
I have a tripod but it has a smaller bolt.

[Bruce Parker (RIP)]

There is an artillery plotting board (like this Canadian one in the pic) but in surveying there is also a 'plane table' for plotting locations of features to create a topographical map, which might be what you have.

[rob love]

I recently picked up the tripod for these items if anyone wants to see it.

[cletrac (RIP)]

Maybe it's just called a map board. It's the right size to fit in the holding brackets behind the radio operator's seat in a 1A2 wireless body. Rob, lets see a picture of your tripod.

[cletrac (RIP)]

I came across a bunch of map-related stuff but don't know what would be relevant. It's shown here with the map board and tripod.
That little square black thing is a neat US morse code training device. There's also a proportional divider in the mail.

[cletrac (RIP)]

Here's a plane table from the manual of map reading 1939. They talk like these are the tolls you need when map reading etc. What's the thing that I didn't label?