[OSRS-PROJ] Unknown USSR projection
Gerald Evenden
gerald.evenden at verizon.net
Mon Mar 8 08:38:42 PST 2004
Looking at it with dividers and a ruler it looks to be a conic and
spacing
of parallels eliminates equidistant. The parallels are at 10 degree
intervals.
but the longitude appears to be at 10 degree intervals as well but I
find
odd discrepancies when comparing locations of the inland seas and
arctic islands with an old Goode atlas. Soviet disinformation, maybe??
;-)
From what can be seen from the spacing of the parallels I would guess
conformal so try Lambert Conformal Conic (lcc) as a first guess with
tangential latitude near the center. Scaling will be trial and error.
PS: a lot of Soviet map projections are covered by Maling in "A Review
of Some Russian Map Projection" in addition to the aforementioned Snyder
reference.
> 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 but the book itself contains no projection
> details. The image is on the web:
> http://www.bio.ic.ac.uk/research/iowens/orme/FlintMap.png.
>
> The only latitude or longitude mark on the map is 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 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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