Re: [PanoTools-devel] Albers Equal Area Conic Projection

 Re: [PanoTools-devel] Albers Equal Area Conic Projection From: Daniel M. German - 2007-03-24 01:42:53 ```I am trying to reduce the size of my mailbox and I finding some older messages. yuval> --- "Michael Gross (adv)" wrote: >> I wrote something about the changes in >> http://mdgrosse.net/pano/albersequalareaconic.txt yuval> thanks! to understand it better, I have a couple of yuval> questions: yuval> P"60.0 20.0" yuval> are these the two standard parallels? yuval> ? Yes. yuval> let's call them P1 and P2, as in P"P1 P2". yuval> What is the possible value range for P1 and P2? Presented by H.C. Albers in 1805, takes two parameters (its standard parallels, corresponding to the parallels where the cone of projection is secant to the sphere). When both are one of the poles then it becomes a Lambert Equal Area Azimuthal. When both are the horizon, it becomes a Lambert Equal Area Cylindrical. yuval> does one of them have to be always larger than the yuval> other? or are there no limitations? Imagine a cone. The cone cuts the sphere at the place where the parallels are. The order of the parallels does not matter, but their sign does. yuval> is P1=P2 acceptable? if it is not acceptable, will yuval> there be an error code returning? Yes, see above. If P1=P2=90, or 0 then an error is returned. It should automatically compute the corresponding cylindrical or azimuthal. yuval> what are sensible values? I really don't like the projection :) yuval> what is the effect of a larger/smaller difference yuval> between P1 and P2? The cone becomes tangent to the sphere at that point. yuval> what is the effect of smaller/larger numbers? Load an equirectilinear in hugin and play with it. yuval> I mean: it is intuitive to me that there will be two yuval> factors changing: the height of the cone (the yuval> development will be more or less vertically stretched) yuval> and its width (which will cover more or less of the yuval> circle). I am trying to understand how the two input yuval> factors relate to these two output observation. yuval> Yuv yuval> __________________________________________________ yuval> Do You Yahoo!? yuval> Tired of spam? Yahoo! Mail has the best spam protection around yuval> http://mail.yahoo.com yuval> ------------------------------------------------------------------------- yuval> Take Surveys. Earn Cash. Influence the Future of IT yuval> Join SourceForge.net's Techsay panel and you'll get the chance to share your yuval> opinions on IT & business topics through brief surveys - and earn cash yuval> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV yuval> _______________________________________________ yuval> PanoTools-devel mailing list yuval> PanoTools-devel@... yuval> https://lists.sourceforge.net/lists/listinfo/panotools-devel -- DMG ```