# Improved Gold 1.0 Depth Maps¶

Contact: Eli Rykoff

See Translating Mangle Masks Into Data Units for details on the problem and the original runs.

These are improved and run with a Random Forest classifier to correlate the systematics with the measured depth.

## Details¶

A draft of a short paper on the methodology as applied to SDSS DR8 is here .

## Files¶

In addition to the files linked to from the SVA1 Gold Catalog v1.0 page, there are additional small files describing the relationship between t_eff and m_lim (see paper linked above).

Each of these files is a small structure with 5 elements (grizY). Each element has a two-element FIT array. The header has the pivot point (23.0 in all cases). To compute t_eff, the effective exposure time, from the 10sigma limiting magnitude m_lim:

t_eff = exp(fit0+fit1*(m_lim-23.0))

## Translating 10sigma Limits into 5sigma Limits¶

With m_lim and t_eff, we can solve eqns 1,5,6,7 in the depth draft to translate the 10sigma limits into 5sigma limits:

```n2=5.0^2
zp=22.5
flim10 = 10.^((m_lim - zp)/(-2.5))
fn = ((flim10^2.*t_eff)/(10.0^2.) - flim10)
flim5 = (n2 + sqrt(n2^2. + 4*t_eff*n2*fn))/(2.*t_eff)

m_lim_5 = zp - 2.5*log10(flim5)
```

## Some Pictures¶

The reconstructed depth map for all of SVA1, auto, i-band, along with the residuals:  And a zoom in on SPTE:  And SPTE for r (auto):  And i (detmodel):  Note that the residuals are definitely worse in the corner with RA~85, Dec ~-57. However, as shown in the paper above some of this may be caused by rapid depth changes and the relatively coarse pixelization used to measure and plot the depth. I have not yet had a chance to run the full analysis using fake data which will be able to quantify these effects.