Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Hi, apologies in advance for an almost 'do my work' question, but I'm a bit stumped as to where to start with something. I wish to draw a plot with North-South and East-West axes upon which is drawn an incomplete grid of points. For each point I wish to have a circle drawn which is filled with a colour indicating the strength of the data point. Problems with this: (1) I want to label the axes with a minimum of fuss, so I'd like to preserve their values (not 0->array size) from the start. (2) How can I draw filled circles? (3) How can I get the filled cirles to automatically scale according to their value? Mmm, not as clear as I wished. You see I had a program to use TRIANGULATE and TRIGRID to remap my 2d array of data onto a large grid and then print that as filled contours, however my data is strictly not from points, its from a 'region', hence the filled circle alternate approach. The problem is that I'm finding it very difficult to do, I basically can't get started. Any advice? I can't quite think of an approach for this. E-mail and post please, my newserver does tend to pass out from excitment now and again and, as this is work related, I'd rather not miss a post that way. Thanks. -- David Kennedy, Dept. of Pure & Applied Physics, Queen's University of Belfast Email: D.Kennedy@Queens-Belfast.ac.uk | URL: http://star.pst.qub.ac.uk/~dcjk/ Hi! I'm a .signature virus! Copy me into yours and join the fun!
David Fanning gave good tips for the original post from David Kennedy and supplied source code to return circle coordinates. The code uses a for loop to calculate the coordinates. It is generally better to use IDL's implicit array handling. An IDL function using my preferred method would look like: function circle, xcenter, ycenter, radius a = (2*!pi/99.)*findgen(100) x = xcenter + radius * cos(a) y = ycenter + radius * sin(a) return, transpose([[x],[y]]) end Best regards Kevin -- Kevin Ivory Tel: +49 5556 979 434 Max-Planck-Institut fuer Aeronomie Fax: +49 5556 979 240 Postfach 20 mailto:kivory2@gwdg.de D-37189 Katlenburg-Lindau, GERMANY http://www.gwdg.de/~kivory2/