I realised the TGI equation may be erroneous thsu I removed it. I am surprised that no one questioned it before so hopefully it was not used much.

app/api/formulas.py

@@ -54,10 +54,6 @@ algos = {
         'expr': '(2 * G) - (R + B)',
         'help': _('Excess Green Index (derived from only the RGB bands) emphasizes the greenness of leafy crops such as potatoes.')
     },
-    'TGI': {
-        'expr': '(G - 0.39) * (R - 0.61) * B',
-        'help': _('Triangular Greenness Index (derived from only the RGB bands) performs similarly to EXG but with improvements over certain environments.')
-    },
     'BAI': {
         'expr': '1.0 / (((0.1 - R) ** 2) + ((0.06 - N) ** 2))',
         'help': _('Burn Area Index hightlights burned land in the red to near-infrared spectrum.')