<html><body name="Mail Message Editor"><div><br></div><div>Dear Corrado:</div><div><br></div><div>At the scales you are working with, there is no point in worrying about ellipsoids. Spherical development is fine. You should use Albers equal area conic for North America and Eurasia, choosing standard parallels inset about 1/6th from the continental north/south extremes. Lambert azimuthal equal-area will work well with South America, Australia, and Antarctica each separately if you use the oblique case, centering it in the center of the continent.</div><div><br></div><div>Regards,</div><div>— daan Strebe</div><div><br></div><br>On Dec 10, 2008, at 12:49:52 AM, Corrado <ct529@york.ac.uk> wrote:<br><blockquote style="padding-left: 5px; margin-left: 5px; border-left-width: 2px; border-left-style: solid; border-left-color: blue; color: blue; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: -webkit-monospace; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">Dear Daan,<br><br>yes, 20 km x 20 km would be the higher resolution, but I do not think we have<span class="Apple-converted-space"> </span><br>enough data to work at that resolution. Our data have all different<span class="Apple-converted-space"> </span><br>resolutions, we will need to aggregate them ....<br><br>Yes, the map is supposed to fit on the journal pages .... let's say maximum<span class="Apple-converted-space"> </span><br>A4.<br><br>PS: Is Lambert a good choice also for other continents? For another project I<span class="Apple-converted-space"> </span><br>have to choose a projection / ellipsoid / datum , equal area, that is good<span class="Apple-converted-space"> </span><br>for the whole world, with the smallest data cell at 10km x 10km. I would need<span class="Apple-converted-space"> </span><br>to draw continental maps as well as some country maps. Do you think it is<span class="Apple-converted-space"> </span><br>better to open a new thread altogether?<br><br>Best,<br></span></blockquote><br><div><br></div><div class="aol_ad_footer" id="u9A910C7540BD453A99482829CC8975D3"></div></body></html>