diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+0.0.18
+
+* Update dependency on `radian`.
+
 0.0.17
 
 * Include prisms for radians. Requires a dependency on the `radian` package.
diff --git a/coordinate.cabal b/coordinate.cabal
--- a/coordinate.cabal
+++ b/coordinate.cabal
@@ -1,5 +1,5 @@
 name:               coordinate
-version:            0.0.17
+version:            0.0.18
 license:            BSD3
 license-file:       LICENCE
 author:             Tony Morris <ʇǝu˙sıɹɹoɯʇ@ןןǝʞsɐɥ>
@@ -33,7 +33,7 @@
                     , lens >= 4.0
                     , tagged >= 0.7
                     , transformers >= 0.3.0.0
-                    , radian >= 0.0.1
+                    , radian >= 0.0.4
 
   ghc-options:
                     -Wall
diff --git a/src/Data/Geo/Coordinate/Latitude.hs b/src/Data/Geo/Coordinate/Latitude.hs
--- a/src/Data/Geo/Coordinate/Latitude.hs
+++ b/src/Data/Geo/Coordinate/Latitude.hs
@@ -9,7 +9,7 @@
 ) where
 
 import Control.Applicative(Applicative)
-import Control.Category(Category(id, (.)))
+import Control.Category(Category(id))
 import Control.Lens(Choice, Profunctor, Optic', iso, prism', lens, (#), (^?))
 import Control.Monad(Monad(return))
 import Data.Eq(Eq)
@@ -18,7 +18,6 @@
 import Data.Geo.Coordinate.Minutes(AsMinutes(_Minutes), Minutes)
 import Data.Geo.Coordinate.Seconds(AsSeconds(_Seconds), Seconds)
 import Data.Ord(Ord((<)))
-import Data.Radian(Radian, radians)
 import Prelude(Double, Show, Int, Num((+), (*), (-), abs), Fractional((/)), properFraction, fromIntegral)
 
 -- $setup
@@ -124,35 +123,6 @@
                  m' <- (abs m :: Int) ^? _Minutes
                  s' <- (abs s * 60) ^? _Seconds
                  return (Latitude d' m' s'))
-
--- | A prism on latitude to a double between -π2 and π2 exclusive. 
---
--- >>> (0.2 :: Radian Double) ^? _Latitude
--- Just (Latitude (DegreesLatitude 11) (Minutes 27) (Seconds 32.9612))
---
--- >>> (1.3 :: Radian Double) ^? _Latitude
--- Just (Latitude (DegreesLatitude 74) (Minutes 29) (Seconds 4.2481))
---
--- >>> (-1.3 :: Radian Double) ^? _Latitude
--- Just (Latitude (DegreesLatitude (-74)) (Minutes 29) (Seconds 4.2481))
---
--- >>> (1.5707963 :: Radian Double) ^? _Latitude
--- Just (Latitude (DegreesLatitude 89) (Minutes 59) (Seconds 59.9945))
---
--- >>> (1.58 :: Radian Double) ^? _Latitude
--- Nothing
---
--- >>> (-1.58 :: Radian Double) ^? _Latitude
--- Nothing
---
--- >>> fmap (\x -> _Latitude # x  :: Radian Double) (do deg <- (7 :: Int) ^? _DegreesLatitude; min <- (7 :: Int) ^? _Minutes; sec <- (7 :: Double) ^? _Seconds; (deg, min, sec) ^? _Latitude :: Maybe Latitude)
--- Just (Radian 0.12424320205794079)
---
--- >>> fmap (\x -> _Latitude # x  :: Radian Double) (do deg <- (89 :: Int) ^? _DegreesLatitude; min <- (15 :: Int) ^? _Minutes; sec <- (6 :: Double) ^? _Seconds; (deg, min, sec) ^? _Latitude :: Maybe Latitude)
--- Just (Radian 1.5577354462258055)
-instance (Choice p, Applicative f) => AsLatitude p f (Radian Double) where
-  _Latitude =
-    radians . _Latitude
 
 instance (p ~ (->), Functor f) => AsDegreesLatitude p f Latitude where
   _DegreesLatitude =
diff --git a/src/Data/Geo/Coordinate/Longitude.hs b/src/Data/Geo/Coordinate/Longitude.hs
--- a/src/Data/Geo/Coordinate/Longitude.hs
+++ b/src/Data/Geo/Coordinate/Longitude.hs
@@ -9,7 +9,7 @@
 ) where
 
 import Control.Applicative(Applicative)
-import Control.Category(Category(id, (.)))
+import Control.Category(Category(id))
 import Control.Lens(Choice, Profunctor, Optic', iso, prism', lens, (#), (^?))
 import Control.Monad(Monad(return))
 import Data.Eq(Eq)
@@ -18,7 +18,6 @@
 import Data.Geo.Coordinate.Minutes(AsMinutes(_Minutes), Minutes)
 import Data.Geo.Coordinate.Seconds(AsSeconds(_Seconds), Seconds)
 import Data.Ord(Ord((<)))
-import Data.Radian(Radian, radians)
 import Prelude(Double, Show, Int, Num((+), (*), (-), abs), Fractional((/)), properFraction, fromIntegral)
 
 -- $setup
@@ -124,35 +123,6 @@
                    m' <- (abs m :: Int) ^? _Minutes
                    s' <- (abs s * 60) ^? _Seconds
                    return (Longitude d' m' s'))
-
--- | A prism on longitude to a double between -π and π exclusive.
---
--- >>> (0.2 :: Radian Double) ^? _Longitude
--- Just (Longitude (DegreesLongitude 11) (Minutes 27) (Seconds 32.9612))
---
--- >>> (1.3 :: Radian Double) ^? _Longitude
--- Just (Longitude (DegreesLongitude 74) (Minutes 29) (Seconds 4.2481))
---
--- >>> (-1.3 :: Radian Double) ^? _Longitude
--- Just (Longitude (DegreesLongitude (-74)) (Minutes 29) (Seconds 4.2481))
---
--- >>> (3.14159 :: Radian Double) ^? _Longitude
--- Just (Longitude (DegreesLongitude 179) (Minutes 59) (Seconds 59.4527))
---
--- >>> (3.15 :: Radian Double) ^? _Longitude
--- Nothing
---
--- >>> (-3.15 :: Radian Double) ^? _Longitude
--- Nothing
---
--- >>> fmap (\x -> _Longitude # x :: Radian Double) (do deg <- (7 :: Int) ^? _DegreesLongitude; min <- (7 :: Int) ^? _Minutes; sec <- (7 :: Double) ^? _Seconds; (deg, min, sec) ^? _Longitude :: Maybe Longitude)
--- Just (Radian 0.12424320205794079)
---
--- >>> fmap (\x -> _Longitude # x :: Radian Double) (do deg <- (179 :: Int) ^? _DegreesLongitude; min <- (15 :: Int) ^? _Minutes; sec <- (6 :: Double) ^? _Seconds; (deg, min, sec) ^? _Longitude :: Maybe Longitude)
--- Just (Radian 3.1285317730207023)
-instance (Choice p, Applicative f) => AsLongitude p f (Radian Double) where
-  _Longitude =
-    radians . _Longitude
 
 instance (p ~ (->), Functor f) => AsDegreesLongitude p f Longitude where
   _DegreesLongitude =