Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
I want to use bilinear to interpolate. I have the values of five points: (x1,y1,t1),(x2,y2,t2),(x3,y3,t3),(x4,y4,t4),(x5,y5,t5). Suppose t is the function of x and y:t=t(x,y). Now I want to know the value of t at the given point(x,y).How can I use bilinear routine to interpolate? According to the manual,the bilinear need three arguments: bilinear(p,ix,jy) P is a 2 dimensional array. Ix and jy are "virtual subscripts" of p. If p is 2 dimension,how can I feed in the values of (x1,y1,z1)...? What is the meaning of "virtual subscripts"? There is another method.If I suppose the general form of bilinear function:t=ax+by+cxy+d.I can get the coefficents(a,b,c,d) using some routines,but?????