[GRASSLIST:2825] Off Topic: Unknown USSR Projection

[David Orme]

Hi,

Not directly grass related but I wondered if anybody can help me 
identify a projection. I need to digitize some range maps from a book 
on the birds of the USSR: all the maps share the same basemap and I've 
attached a scan of an example. The book itself contains no projection 
details.

The map marks the arctic circle: as far as I can make out this is an 
arc from a circle, although there is a hint that at the edges of the 
map the arc may turn down away from the circle. I've tried identifying 
10 degree lines of latitude and longitude from locations around the map 
edge (on the attached image) and that suggests to me that the map is 
projected on something like a equidistant conic or albers projection. 
What I've got so far:

* the central meridian is around 105 E.
* the longitude lines look like they converge on the centre of the 
circle, although if I try and draw them in from geography, they don't 
converge very well.
* a degree of longitude is about 0.4 degrees of arc on the projected 
map.
* the latitude lines don't seem to be equally spaced - in particular, 
the 80-70 N gap is wider than the other three latitudinal spacings.

I can't get it to fit - has anyone got any suggestions for projections 
or projection parameters? It doesn't help that I suspect the map is 
rather inaccurately drawn.

Thanks,
David

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