Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
overplotting data and contours for small images
Hello, I have a 16x16 matrix ima.data (which contains a chi-square map) which has been generated by "fit stepping" on two parameters. I know that my parameters range from 10 to 13 and to 142 to 145 (there are 16 steps of 0.2 on each axis). Therefore I plot with : xar=findgen(16)*0.2+10 yar=findgen(16)*0.2+142 contour,ima.data,xar,yar,levels=[0,2.3,4.61,9.21],xrange=[10 ,13],yrange=[142,145] (the levels are the usual 68%, 90% and 99% confidence contours). What I get is that IN THE PLOT the centre of the contours (i.e. the minimum of the image) is located 2 steps left in x (i.e -0.4 from the real x) and 2 steps up in y (i.e. +0.4 from the real y). How does "contour" correlate positions in the image with the x and y arrays ? Are there any artifact due to the fact my images have a small number of pixels ? ------------------------------------------------------------ ---------------- A member of G.ASS : Group for Astronomical Software Support ------------------------------------------------------------ ---------------- Lucio Chiappetti - IFCTR/CNR | Ma te' vugl' da' quost avis a ti' Orsign via Bassini 15 - I-20133 Milano | Buttet rabios intant te se' pisnign Internet: LUCIO@IFCTR.MI.CNR.IT | Decnet: IFCTR::LUCIO | (Rabisch, II 46, 119-120) ------------------------------------------------------------ ----------------