From bc67dc9a517d988f77b6f9c6e2b3bffd5f466ce3 Mon Sep 17 00:00:00 2001
From: Piero Toffanin <pt@masseranolabs.com>
Date: Tue, 19 Nov 2019 12:51:17 -0500
Subject: [PATCH] Formula tests

---
 app/api/formulas.py                  | 41 ++++++++++++++++++++--------
 app/static/app/js/components/Map.jsx |  2 +-
 app/tests/test_formulas.py           | 18 ++++++++++++
 3 files changed, 49 insertions(+), 12 deletions(-)
 create mode 100644 app/tests/test_formulas.py

diff --git a/app/api/formulas.py b/app/api/formulas.py
index d57fe574..3e74c963 100644
--- a/app/api/formulas.py
+++ b/app/api/formulas.py
@@ -1,25 +1,44 @@
 # Algos from https://github.com/dirceup/tiled-vegetation-indices/blob/master/app/lib/vegetation_index.rb
 import re
+from functools import lru_cache
 
+
+# Functions can use all of the supported functions and operators from
+# https://numexpr.readthedocs.io/en/latest/user_guide.html#supported-operators
 algos = {
-    'vari': {
+    'VARI': {
         'bands': 'RGB',
-        'expr': '(G-R)/(G+R-B)'
+        'expr': '(G - R) / (G + R - B)',
+        'help': 'Visual Atmospheric Resistance Index shows the areas of vegetation.'
+    },
+    'NDVI': {
+        'bands': 'RGN',
+        'expr': '(N - R) / (N + R)',
+        'help': 'Normalized Difference Vegetation Index shows the amount of green vegetation.'
+    },
+    'BAI': {
+        'bands': 'RGN',
+        '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.'
+    },
+    'GLI': {
+        'bands': 'RGB',
+        'expr': '((G * 2) - R - B) / ((G * 2) + R + B)',
+        'help': 'Green Leaf Index shows greens leaves and stems.'
+    },
+    'GNDVI':{
+        'bands': 'RGN',
+        'expr': '(N - G) / (N + G)',
+        'help': 'Green Normalized Difference Vegetation Index is similar to NDVI, but measures the green spectrum instead of red.'
     },
 
-    'TEST': {
+    '_TESTRB': {
         'bands': 'RGB',
         'expr': 'B+R'
     }
 }
 
-band_map = {
-    'RGB': (0, 1, 2),
-
-
-    'BGR': (2, 1, 0),
-}
-
+#@lru_cache(max_size=20)
 def lookup_formula(algo, band_order = 'RGB'):
     if algo is None:
         return None
@@ -38,4 +57,4 @@ def lookup_formula(algo, band_order = 'RGB'):
         b = matches.group(1)
         return 'b' + str(input_bands.index(algo_bands.index(b)) + 1)
 
-    return re.sub("([A-Z]+?[a-z]*)", repl, algos[algo]['expr'])
+    return re.sub("([A-Z]+?[a-z]*)", repl, re.sub("\s+", "", algos[algo]['expr']))
diff --git a/app/static/app/js/components/Map.jsx b/app/static/app/js/components/Map.jsx
index 6de8219f..37b0853d 100644
--- a/app/static/app/js/components/Map.jsx
+++ b/app/static/app/js/components/Map.jsx
@@ -94,7 +94,7 @@ class Map extends React.Component {
         const { url, meta, type } = tile;
         
         let metaUrl = url + "metadata";
-        if (type == "plant") metaUrl += "?formula=vari&bands=RGB&rescale=0.02,0.1&color_map=rdylgn";
+        if (type == "plant") metaUrl += "?formula=GLI&bands=RGB&rescale=-1,1&color_map=rdylgn";
         if (type == "dsm") metaUrl += "?rescale=156%2C165&hillshade=3&color_map=jet_r";
 
         console.log(type, metaUrl);
diff --git a/app/tests/test_formulas.py b/app/tests/test_formulas.py
new file mode 100644
index 00000000..45fc1b18
--- /dev/null
+++ b/app/tests/test_formulas.py
@@ -0,0 +1,18 @@
+from django.test import TestCase
+from app.api.formulas import lookup_formula
+
+class TestFormulas(TestCase):
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_formulas(self):
+        # Original
+        self.assertTrue(lookup_formula("_TESTRB", "RGB") == "b3+b1")
+
+        # Swap bands
+        self.assertTrue(lookup_formula("_TESTRB", "BGR") == "b1+b3")
+        self.assertTrue(lookup_formula("_TESTRB", "NRB") == "b2+b3")
+