Data.GPS

Author: Thomas DuBuisson Copyright: Thomas DuBuisson License: BSD3

A basic GPS library with calculations for distance and speed along with helper functions for filtering/smoothing trails. All distances are in meters and time is in seconds. Speed is thus meters/second

The current intent of this library is to 1) Provide a standard type class interface for coordinates 2) Include fleshed out support for relevant libraries, a task too often neglected in modern Hackage packages.

Integration includes KML support via the xml package, pretty printing, anb binary.

Types and Classes

class Coordinate a where

A coordinate is a place on earths surface. While twoDMS and fromDMS are the only required functions, coordinate systems may provide more accurate calculations of heading, distance, and vectors without the intermediate translation.

Methods

toDMS :: a -> DMSCoordinate

fromDMS :: DMSCoordinate -> a

distance :: a -> a -> Distance

heading :: a -> a -> Heading

getVector :: a -> a -> Vector

Instances

Coordinate DMSCoordinate

Coordinate c => Coordinate (c, UTCTime)

class Coordinate coord => Location loc coord time | loc -> coord, loc -> time where

A location is a coordinate at a specific time

Methods

getCoordinate :: loc -> coord

getTime :: loc -> time

getUTC :: loc -> UTCTime

speed :: loc -> loc -> Speed

Instances

Coordinate c => Location (c, UTCTime) c UTCTime

data DMSCoordinate

DMSCoordinate is the typical degree minute second for latitude/longitude used by most civilian GPS devices.

Constructors

DMSCoord

Fields

latitude :: DMS Latitude

longitude :: DMS Longitude

Instances

Eq DMSCoordinate

Ord DMSCoordinate

Read DMSCoordinate

Show DMSCoordinate

Binary DMSCoordinate

Pretty DMSCoordinate

Coordinate DMSCoordinate

data DMS a

DMS is the degrees, minutes, seconds used for both latitude and longitude

Constructors

DMS

Fields

degrees :: Double

minutes :: Double

seconds :: Double

Instances

Eq (DMS a)

Ord (DMS a)

Read (DMS a)

Show (DMS a)

data Latitude

Empty declaration for phantom type

data Longitude

Empty declaration for phantom type

type Distance = Double

Distances are expressed in meters

type Heading = Double

Angles are expressed in radians from North. 0 == North pi/2 == West pi == South (32)pi == East == - (pi 2)

type Speed = Double

Speed is hard coded as meters per second

type Vector = (Distance, Heading)

type Trail a = [a]

Constants

north :: Integer

south :: Double

east :: Double

west :: Double

radiusOfEarth :: Double

radius of the earth in meters

Helper Functions

smoothTrails :: Location a b c => Speed -> Trail a -> [Trail a]

smoothTrails speed trail should separate points that would mandate a speed in excess of the given rate into separate Trails. No point are deleted; if there is only one correct trail expected then the largest resulting trail will likely be the one your looking for.

longestSmoothTrail :: Location a b c => Speed -> Trail a -> Trail a

Uses smoothTrails but returns only the longest resulting trail

restLocations :: Location a b c => Distance -> NominalDiffTime -> Trail a -> [Trail a]

Creates a list of trails all of which are within the given distance of each other spanning atleast the given amount of time.

For example restLocations 50 600 would return lists of all points that are within 50 meters of each other and span at least 10 minutes (600 seconds).

Note this gives points within fifty meters of the earliest point - wandering in a rest area with a 50 meter radius could result in several rest points ([a,b..]) or even none if the distance between individual points exceeds 50m.

closestDistance :: Coordinate a => Trail a -> Trail a -> Maybe Distance

Returns the closest distance between two trails (or Nothing if a trail is empty) O( (n * m) * log (n * m) )

normalizeDMS :: DMSCoordinate -> DMSCoordinate

Typically useful for printing, normalizes degrees, minutes, seconds into just degrees and decimal minutes:

DMSCoord (DMS 45 36.938455 0) (DMS ...)

dmsToDegreePair :: DMSCoordinate -> (Double, Double)

Provides a lat/lon pair of doubles in degrees

dmsToRadianPair :: DMSCoordinate -> (Double, Double)

Provides a lat/lon pair of doubles in radians

degreePairToDMS :: (Double, Double) -> DMSCoordinate

addVector :: Vector -> DMSCoordinate -> DMSCoordinate

Given a vector and coordinate, computes a new DMS coordinate. Within some epsilon it should hold that if

dest = addVector (dist,heading) start

then

heading == dmsHeading start dest

dist    == distance start dest