naqsha-0.2.0.1: A library for working with geospatial data types.

Safe HaskellNone
LanguageHaskell2010

Naqsha.Geometry

Contents

Description

The geometric types and values exposed by naqsha.

Synopsis

Basics

A point on the globe is specified by giving its geo coordinates represented by the type Geo. It is essentially a pair of the Latitude and Longitude of the point.

Examples

kanpurLatitude  :: Latitude
kanpurLatitude  = lat $ degree 26.4477777
kanpurLongitude :: Longitude
kanpurLongitude = lon $ degree 80.3461111
kanpurGeo       :: Geo
kanpurGeo       = Geo kanpurLatitude kanpurLongitude

You can also specify the latitude and longitude in units of degree, minute and seconds.

kanpurLatitude  = lat $ degree 26 <> minute 26 <> second 52
kanpurLongitude = lon $ degree 80 <> minute 20 <> second 46

The show and read instance of the Latitude and Longitude types uses degrees for displaying and reading respectively. Show and Read instances can express these quantities up to Nano degree precision.

Convention on sign.

For latitudes, positive means north of the equator and negative means south. In the case of longitudes, positive means east of the longitude zero and negative means west. However, if you find these conventions confusing you can use the combinators north, south, east, and west when constructing latitudes or longitudes.

data Geo #

The coordinates of a point on the earth's surface.

Constructors

Geo !Latitude !Longitude 

Instances

Eq Geo # 

Methods

(==) :: Geo -> Geo -> Bool #

(/=) :: Geo -> Geo -> Bool #

Show Geo # 

Methods

showsPrec :: Int -> Geo -> ShowS #

show :: Geo -> String #

showList :: [Geo] -> ShowS #

Vector Vector Geo # 
MVector MVector Geo # 
data Vector Geo # 
data MVector s Geo # 

northPole :: Geo #

The North pole

southPole :: Geo #

The South pole

Latitudes

data Latitude #

The latitude of a point. Positive denotes North of Equator where as negative South.

Instances

Bounded Latitude # 
Eq Latitude # 
Ord Latitude # 
Read Latitude # 
Show Latitude # 
Bits Latitude # 
Angular Latitude # 

Methods

toAngle :: Latitude -> Angle #

Vector Vector Latitude # 
MVector MVector Latitude # 
data Vector Latitude # 
data MVector s Latitude # 

lat :: Angle -> Latitude #

Construct latitude out of an angle.

north :: Angle -> Latitude #

Convert an angle to a northern latitude

tropicOfCancer = north $ degree 23.5

south :: Angle -> Latitude #

Convert an angle to a southern latitude.

 tropicOfCapricon = south $ degree 23.5

equator :: Latitude #

The latitude of equator.

tropicOfCancer :: Latitude #

The latitude corresponding to the Tropic of Cancer.

tropicOfCapricon :: Latitude #

The latitude corresponding to the Tropic of Capricon

Longitudes.

data Longitude #

The longitude of a point. Positive denotes East of the Greenwich meridian where as negative denotes West.

Instances

Bounded Longitude # 
Eq Longitude # 
Ord Longitude # 
Read Longitude # 
Show Longitude # 
Monoid Longitude # 
Bits Longitude # 
Group Longitude # 
Angular Longitude # 

Methods

toAngle :: Longitude -> Angle #

Vector Vector Longitude # 
MVector MVector Longitude # 
data Vector Longitude # 
data MVector s Longitude # 

lon :: Angle -> Longitude #

Convert angles to longitude.

east :: Angle -> Longitude #

Convert angle to an eastern longitude.

kanpurLongitude = east $ degree 80.3461

west :: Angle -> Longitude #

Convert angle to a western longitude

newyorkLongitude = west $ degree 74.0059

greenwich :: Longitude #

The zero longitude.

Angles and angular quantities.

data Angle #

An abstract angle. Internally, angles are represented as a 64-bit integer with each unit contribute 1/2^64 fraction of a complete circle. This means that angles are accurate up to a resolution of 2 π / 2^64 radians. Angles form a group under the angular addition and the fact that these are represented as integers means one can expect high speed accurate angle arithmetic.

When expressing angles one can use a more convenient notation:

myAngle   = degree 21.71167
yourAngle = degree 21 <> minute 42 <> second 42

Instances

Bounded Angle # 
Enum Angle # 
Eq Angle # 

Methods

(==) :: Angle -> Angle -> Bool #

(/=) :: Angle -> Angle -> Bool #

Ord Angle # 

Methods

compare :: Angle -> Angle -> Ordering #

(<) :: Angle -> Angle -> Bool #

(<=) :: Angle -> Angle -> Bool #

(>) :: Angle -> Angle -> Bool #

(>=) :: Angle -> Angle -> Bool #

max :: Angle -> Angle -> Angle #

min :: Angle -> Angle -> Angle #

Read Angle # 
Show Angle # 

Methods

showsPrec :: Int -> Angle -> ShowS #

show :: Angle -> String #

showList :: [Angle] -> ShowS #

Monoid Angle # 

Methods

mempty :: Angle #

mappend :: Angle -> Angle -> Angle #

mconcat :: [Angle] -> Angle #

Bits Angle # 
Group Angle # 

Methods

invert :: Angle -> Angle #

pow :: Integral x => Angle -> x -> Angle #

Unbox Angle # 
Angular Angle # 

Methods

toAngle :: Angle -> Angle #

Vector Vector Angle # 
MVector MVector Angle # 
data Vector Angle # 
data MVector s Angle # 

degree :: Rational -> Angle #

Express angle in degrees.

minute :: Rational -> Angle #

Express angle in minutes.

second :: Rational -> Angle #

Express angle in seconds.

radian :: Double -> Angle #

Express angle in radians

toDegree :: Fractional r => Angle -> r #

Measure angle in degrees. This conversion may lead to loss of precision.

toRadian :: Angle -> Double #

Measure angle in radians. This conversion may lead to loss of precision.

class Angular a where #

Angular quantities.

Minimal complete definition

toAngle

Methods

toAngle :: a -> Angle #

Instances

Geometric hashing.

Geometric hashing is a technique of converting geometric coordinates into 1-dimension strings. Often these hashes ensures that string with large common prefix are close by (although not the converse). Hence, these hashes can be used to stored geo-cordinates in database and build into it a sense of location awareness. We support the following geometric hashing:

Naqsha.Geometry.Coordinate.GeoHash:
The geohash standard (https://en.wikipedia.org/wiki/Geohash).

None of these modules are imported by default the user may import the one that is most desirable.

Distance calculation.

Calculating quantities like distance, bearing etc depends on the model of the globe that we choose. Even in a given model we might have different algorithms to compute the distance depending on speed-accuracy trade-offs. Choosing the correct model and algorithms is application dependent and hence we do not expose any default ones. The following modules can be imported depending on the need

Naqsha.Geometry.Spherical:
Assume a spherical model of the globe. Distance is calculated using the haversine formula.

Internal details

The basic types like Latitude or Longitude are exposed as opaque types from this module. For type safety, we encourage the users to use this module mostly when dealing with those times. For the rare case when some non-trivial operations need to be defined, we expose the internal module Naqsha.Geometry.Internal. However, use this interface with caution.