<DIV id=RTEContent> <DIV>Hi;</DIV> <DIV> </DIV> <DIV><A href="http://grass.itc.it/searchgrass.php">http://grass.itc.it/searchgrass.php</A></DIV> <DIV> </DIV> <DIV>may help you to search mailing list archives.</DIV> <DIV> </DIV> <DIV>Muzaffer...<BR><BR><B><I>Dmitry Suzdalev <dimsuz@mail.ru></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi, dear GRASS developers :).<BR>Please, sorry for maybe offtopic, but I have one question.<BR>I'm learning my way into world of map projections and my task is to display <BR>all the world in a GUI window (QT-window, actually).<BR>I've already managed to do it, using libproj4 :).<BR>But... There is sooo much data to be displayed that it draws rather slow.<BR><BR>And it's obvious, that it's not needed to draw EACH map data primitive, <BR>because some of them are so small, that they're represented by one pixel, <BR>when using large scales. And still,
if I have 1000 primitives (polylines, <BR>regions etc) that are so small, that they fit in one concrete pixel, they'll <BR>all be drawn. In the same pixel. 1000 times. That's slow :).<BR><BR>So the question is: is there any common algorithm to cope with this situation? <BR>Which helps to somehow "filter out" the primitives which are represented by a <BR>single pixel at the screen and draw that pixel only once?<BR>Or should i investigate that algorithm by myself? :)<BR><BR>Again, sorry if this is offtopic, I've googled for a few hours trying to find <BR>some kind of web-forum for such kind of questions, but I didn't find it :).<BR>Googling on "gis developers forum" pointed me to your mailing list, so I <BR>decided to give it a try :).<BR><BR>Maybe at least, you can point me to the right place to ask such a question? :)<BR><BR>Thanks in advance!<BR><BR>And sorry for my maybe not very good English ;).<BR>Cheers, Dmitry.<BR><BR>_______________________________________________<BR>grass5
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