Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
I am fairly new to IDL and am having trouble with the map_set function making an orthographic projection. I can do the default, but in the reference guide it says "If the keyword LIMIT is not set, the region of the globe mapped to the UV plane is the hemisphere around the center of the projection." I am doing a plot with the North pole centered and would like to limit the plot at 30deg, but I can't figure out how to make the LIMIT keyword work properly for this projection style. Folowing the reference guide directions for LIMIT I keep getting floating point errors. Can anyone help? Wayne Keith Rice University (713) 527-8750 ext 3551 http://spacsun.rice.edu/~waynek ------------------------------------------------------------ ----------- Error message of the week: ...File not found. Should I fake it? (Y/N) ------------------------------------------------------------ -----------
In article ya023080001305971750250001@news.frii.com, davidf@dfanning.com (David Fanning) instructed: > Wayne Keith <waynek@spacsun.rice.edu> enquired: >> I am fairly new to IDL and am having trouble with the map_set function >> making an orthographic projection. >> Folowing the >> reference guide directions for LIMIT I keep getting floating point >> errors. Can anyone help? > Polar orthographic? Auh, oh. > I tried this and didn't get any errors: > IDL> Map_Set, /Ortho, 90, 0, /Grid, /Cont, Limit=[30,-180, 90, 180], /Label This works for me too (of course it does, it comes from DF ;-) You might want to add /iso, too). However, you problem with FP errors is familiar... I have a slight feeling that is sometimes occurs when you get the SWNE the wrong way round in the limit variable... but I can't reproduce it just now... ...Haha, yes I can. Actually it seems to occur if you make S and N the same. Look: wmc> Map_Set, /Ortho, 90, /Grid, /Cont, Limit=[80,30, 80, 90], /Label,/iso % Program caused arithmetic error: Floating illegal operand However, this is not a sensible thing to do... - William