Remove dimensional dependence from tests, and more updates.

src/Geodetics/Ellipsoids.hs

@@ -14,28 +14,31 @@ specific area.
 -}
 
 module Geodetics.Ellipsoids (
-   radiansToDegrees,
-   degreesToRadians,
-   -- ** Helmert transform between geodetic reference systems
+   -- * Conversion constants
+   degree,
+   arcminute,
+   arcsecond,
+   kilometer,
+   -- * Helmert transform between geodetic reference systems
    Helmert (..),
    inverseHelmert,
    ECEF,
    applyHelmert,
-   -- ** Ellipsoid models of the Geoid
+   -- * Ellipsoid models of the Geoid
    Ellipsoid (..),
    WGS84 (..),
    LocalEllipsoid (..),
    flattening,
    minorRadius,
    eccentricity2,
    eccentricity'2,
-   -- ** Auxiliary latitudes and related Values
+   -- * Auxiliary latitudes and related Values
    normal,
    latitudeRadius,
    meridianRadius,
    primeVerticalRadius,
    isometricLatitude,
-   -- ** Tiny linear algebra library for 3D vectors
+   -- * Tiny linear algebra library for 3D vectors
    Vec3,
    Matrix3,
    add3,
@@ -49,15 +52,29 @@ module Geodetics.Ellipsoids (
 ) where
 
 
--- | All angles in this library are radians.
-radiansToDegrees :: Double -> Double
-radiansToDegrees = (* (180/pi))
+-- | All angles in this library are in radians. This is one degree in radians.
+degree :: Double
+degree = pi/180
 
+-- | One arc-minute in radians.
+arcminute :: Double
+arcminute = degree / 60
 
-degreesToRadians :: Double -> Double
-degreesToRadians = (* (pi/180))
+-- | One arc-second in radians.
+arcsecond :: Double
+arcsecond = arcminute / 60
 
 
+-- | All distances in this library are in meters. This is one kilometer in meters.
+kilometer :: Double
+kilometer = 1000
+
+
+-- | Small integers, specialised to @Int@, used for raising to powers.
+--
+-- If you say @x^2@ then Haskell complains that the @2@ has ambiguous type, so you
+-- need to say @x^(2::Int)@ to disambiguate it. This gets tedious in complex formulae.
+
 -- | 3d vector as @(X,Y,Z)@.
 type Vec3 a = (a,a,a)
 

src/Geodetics/Geodetic.hs

@@ -1,5 +1,5 @@
 module Geodetics.Geodetic (
-   -- ** Geodetic Coordinates
+   -- * Geodetic Coordinates
    Geodetic (..),
    readGroundPosition,
    toLocal,
@@ -10,11 +10,11 @@ module Geodetics.Geodetic (
    groundDistance,
    properAngle,
    showAngle,
-   -- ** Earth Centred Earth Fixed Coordinates
+   -- * Earth Centred Earth Fixed Coordinates
    ECEF,
    geoToEarth,
    earthToGeo,
-   -- ** Re-exported for convenience
+   -- * Re-exported for convenience
    WGS84 (..)
 ) where
 
@@ -89,7 +89,7 @@ readGroundPosition :: (Ellipsoid e) => e -> String -> Maybe (Geodetic e)
 readGroundPosition e str =
    case map fst $ filter (null . snd) $ readP_to_S latLong str of
       [] -> Nothing
-      (lat,long) : _ -> Just $ groundPosition $ Geodetic (degreesToRadians lat) (degreesToRadians long) undefined e
+      (lat,long) : _ -> Just $ groundPosition $ Geodetic (lat * degree) (long * degree) undefined e
 
 
 -- | Show an angle as degrees, minutes and seconds to two decimal places.
@@ -103,7 +103,7 @@ showAngle a
    where
       sgn = if a < 0 then "-" else ""
       centisecs :: Integer
-      centisecs = abs $ round $ (radiansToDegrees a) * 360000  -- hundredths of arcsec per degree.
+      centisecs = abs $ round $ (a * degree * 360000)  -- hundredths of arcsec per degree.
       (d, m1) = centisecs `divMod` 360000
       (m, s1) = m1 `divMod` 6000   -- hundredths of arcsec per arcmin
       (s, ds) = s1 `divMod` 100
@@ -122,8 +122,8 @@ antipode :: (Ellipsoid e) => Geodetic e -> Geodetic e
 antipode g = Geodetic lat long (geoAlt g) (ellipsoid g)
    where
       lat = negate $ latitude g
-      long' = longitude g - degreesToRadians 180
-      long | long' < 0  = long' + degreesToRadians 360
+      long' = longitude g - 180 * degree
+      long | long' < 0  = long' + 360 * degree
            | otherwise  = long'
 
 
@@ -230,8 +230,8 @@ groundDistance p1 p2 = do
        listToMaybe $ dropWhile converging $ take 100 $ zip lambdas $ drop 1 lambdas
      let
        uSq = cos2Alpha * (a**2 - b**2) / b**2
-       bigA = 1 + uSq/16384 * 4096 + uSq * (-768) + uSq * ((320 - (175*uSq)))
-       bigB =     uSq/1024  * 256  + uSq * (-128) + uSq * ((74 -  (47* uSq)))
+       bigA = 1 + uSq/16384 * (4096 + uSq * ((-768) + uSq * ((320 - 175*uSq))))
+       bigB =     uSq/1024  * (256  + uSq * ((-128) + uSq * ((74 -  47* uSq))))
        deltaDelta =
          bigB * sinDelta * (cos2DeltaM +
                              bigB/4 * (cosDelta * (2 * cos2DeltaM**2 - 1)

src/Geodetics/Grid.hs

@@ -1,11 +1,11 @@
 {-# LANGUAGE FunctionalDependencies #-}
 
 module Geodetics.Grid (
-   -- ** Grid types
+   -- * Grid types
    GridClass (..),
    GridPoint (..),
    GridOffset (..),
-   -- ** Grid operations
+   -- * Grid operations
    polarOffset,
    offsetScale,
    offsetNegate,
@@ -14,9 +14,9 @@ module Geodetics.Grid (
    offsetDistanceSq,
    offsetBearing,
    gridOffset,
-   -- ** Unsafe conversion
+   -- * Unsafe conversion
    unsafeGridCoerce,
-   -- ** Utility functions for grid references
+   -- * Utility functions for grid references
    fromGridDigits,
    toGridDigits
 ) where

src/Geodetics/LatLongParser.hs

@@ -5,7 +5,6 @@
 -- All angles are returned in degrees.
 
 module Geodetics.LatLongParser (
-
    degreesMinutesSeconds,
    degreesMinutesSecondsUnits,
    degreesDecimalMinutes,

src/Geodetics/Stereographic.hs

@@ -115,5 +115,4 @@ instance (Ellipsoid e) => GridClass (GridStereo e) e where
                   e2 = eccentricity2 $ gridEllipsoid grid
          lats = Stream.iterate next lat1
          latN = snd $ Stream.head $ Stream.dropWhile (\(v1, v2) -> abs (v1-v2) > 0.01 * arcsecond) $ Stream.zip lats $ Stream.drop 1 lats
-         arcsecond = degreesToRadians $ 1/3600
    gridEllipsoid = ellipsoid . gridTangent

src/Geodetics/UK.hs

@@ -36,8 +36,6 @@ instance Ellipsoid OSGB36 where
       cX = 446.448, cY = (-125.157), cZ = 542.06,
       helmertScale = (-20.4894),
       rX = 0.1502 * arcsecond, rY = 0.247 * arcsecond, rZ = 0.8421 * arcsecond }
-      where
-         arcsecond = degreesToRadians $ 1/3600
 
 -- | The UK National Grid is a Transverse Mercator projection with a true origin at
 -- 49 degrees North, 2 degrees West on OSGB36, and a false origin 400km West and 100 km North of
@@ -53,8 +51,8 @@ instance GridClass UkNationalGrid OSGB36 where
 
 ukTrueOrigin :: Geodetic OSGB36
 ukTrueOrigin = Geodetic {
-   latitude = degreesToRadians 49,
-   longitude = degreesToRadians (-2),
+   latitude = 49 * degree,
+   longitude = (-2) * degree,
    geoAlt = 0,
    ellipsoid = OSGB36
 }
@@ -63,10 +61,6 @@ ukFalseOrigin :: GridOffset
 ukFalseOrigin = GridOffset ((-400) * kilometer) (100 * kilometer) (0 * kilometer)
 
 
-kilometer :: Double
-kilometer = 1000
-
-
 -- | Numerical definition of the UK national grid.
 ukGrid :: GridTM OSGB36
 ukGrid = mkGridTM ukTrueOrigin ukFalseOrigin