From 79e02b354a80de56ae2d84a041f380aa0e0f87cb Mon Sep 17 00:00:00 2001
From: Luke Campbell <luke.s.campbell@gmail.com>
Date: Tue, 12 Mar 2013 11:40:21 -0400
Subject: [PATCH] Adds ctd_l2_density

---
 ion_functions/data/data_functions.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/ion_functions/data/data_functions.py b/ion_functions/data/data_functions.py
index e93d173..70fe2e2 100644
--- a/ion_functions/data/data_functions.py
+++ b/ion_functions/data/data_functions.py
@@ -16,3 +16,13 @@ def data_density(SP, p, t, lat, lon):
 
     return gsw.rho(abs_sal, cons_temp, p)
 
+def data_l2_density(conductivity, temp,pressure, lat, lon):
+    '''
+    Based on calculations done here: https://github.com/ooici/coi-services/blob/master/ion/processes/data/transforms/ctd/ctd_L2_density.py#L55
+    '''
+    from pygsw import vectors as gsw
+    sp = gsw.sp_from_c(conductivity/42.914, temp, pressure)
+    sa = gsw.sa_from_sp(sp, pressure, lon, lat)
+    rho = gsw.rho(sa, temp, pressure)
+    return rho
+