On 28/06/07, Tim Jenness <[log in to unmask]> wrote:
> We need to fit a 2d plane to our SCUBA-2 data. This works brilliantly
> using KAPPA SURFIT but we need to know the gradient from the fit because
> this provides an estimate (possibly) of the extinction.
>
> SURFIT does not give us these coefficients. FITSURFACE does but doesn't
> seem to be as good as SURFIT (and requires an additional call to
> MAKESURFACE adding 0.1 sec to the pipeline run time).
>
> At the moment we are considering simply collapsing the surface into X and
> Y and then calculating the gradient by looking at the data values at the
> extrema. Bit of a kluge but should work since we know it was a linear fit.
>
> One option is to obtain the coefficients from SURFIT (or even a POLYNOMIAL
> extension like FITSURFACE) but before embarking on this I thought I'd ask
> for opinions in case I've missed something obvious.
Can't think of anything myself.
David
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