i.vi: fix PVI formula (OSGeo#1985)

* Fix wrong mathematical formula in the PVI index computation in i.vi * fix OSGeo#1984
ninsbl · Oct 26, 2022 · de304b0 · de304b0
1 parent 005e99e
commit de304b0
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/imagery/i.vi/pvi.c b/imagery/i.vi/pvi.c
@@ -17,7 +17,7 @@ double p_vi(double redchan, double nirchan)
 	result = -1.0;
     }
     else {
-	result = (sin(1) * nirchan) / (cos(1) * redchan);
+	result = (sin(1) * nirchan) - (cos(1) * redchan);
     }
     return result;
 }