Rename 'value' field to 'threshold' in geojson representation

Author: mthh

src/contour.rs

@@ -265,9 +265,7 @@ impl Contour {
     /// ```
     pub fn to_geojson(&self) -> geojson::Feature {
         let mut properties = geojson::JsonObject::with_capacity(1);
-        // REVIEW: This maintains existing behavior, but should we rename
-        // `value` to something more explicable, like `threshold`?
-        properties.insert("value".to_string(), self.threshold.into());
+        properties.insert("threshold".to_string(), self.threshold.into());
 
         geojson::Feature {
             bbox: None,

src/lib.rs

@@ -38,7 +38,7 @@
 //!       [6., 7.5]
 //!     ]]],
 //!   },
-//!   "properties": {"value": 0.5},
+//!   "properties": {"threshold": 0.5},
 //! });
 //!
 //! assert_eq!(res[0].to_geojson(), std::convert::TryFrom::try_from(output).unwrap());