Copyright	(C) 2014 Dom De Re
License	BSD-style (see the file etc/LICENSE.md)
Maintainer	Dom De Re
Safe Haskell	None
Language	Haskell2010

Data.Geospatial

Contents

Types
Functions
Lenses
- Geometry Lenses
- Feature Lenses
Prisms
- Geometry
- CRS

Description

Refer to the GeoJSON Spec http://www.geojson.org/geojson-spec.html

Synopsis

Types

type Latitude = Double Source

type Longitude = Double Source

type Easting = Double Source

type Northing = Double Source

type Altitude = Double Source

type GeoPositionWithoutCRS = [Double] Source

(GeoPositionWithoutCRS is a catch all for indeterminate CRSs and for expression of positions before a CRS has been determined

data GeoPosition Source

see Section 2.1.1 Position in the GeoJSON Spec, I make the assumption here that the only position types we will use will involve easting or northing (+ve or -ve Altitude) or lon or lat (+ve or -ve Altitude)

Constructors

LonLat Longitude Latitude
LonLatAlt Longitude Latitude Altitude
EastingNorthing Easting Northing
EastingNorthingAlt Easting Northing Altitude

newtype GeoPoint Source

Constructors

GeoPoint
Fields _unGeoPoint :: GeoPositionWithoutCRS

Instances

Eq GeoPoint
Show GeoPoint
ToJSON GeoPoint
FromJSON GeoPoint

newtype GeoMultiPoint Source

Constructors

GeoMultiPoint
Fields _unGeoMultiPoint :: [GeoPositionWithoutCRS]

Instances

Eq GeoMultiPoint
Show GeoMultiPoint
ToJSON GeoMultiPoint
FromJSON GeoMultiPoint

splitGeoMultiPoint :: GeoMultiPoint -> [GeoPoint] Source

Split GeoMultiPoint coordinates into multiple GeoPoints

mergeGeoPoints :: [GeoPoint] -> GeoMultiPoint Source

Merge multiple GeoPoints into one GeoMultiPoint

newtype GeoPolygon Source

Constructors

GeoPolygon
Fields _unGeoPolygon :: [LinearRing GeoPositionWithoutCRS]

Instances

Eq GeoPolygon
Show GeoPolygon
ToJSON GeoPolygon
FromJSON GeoPolygon

newtype GeoMultiPolygon Source

Constructors

GeoMultiPolygon
Fields _unGeoMultiPolygon :: [[LinearRing GeoPositionWithoutCRS]]

Instances

Eq GeoMultiPolygon
Show GeoMultiPolygon
ToJSON GeoMultiPolygon
FromJSON GeoMultiPolygon

splitGeoMultiPolygon :: GeoMultiPolygon -> [GeoPolygon] Source

Split GeoMultiPolygon coordinates into multiple GeoPolygons

mergeGeoPolygons :: [GeoPolygon] -> GeoMultiPolygon Source

Merge multiple GeoPolygons into one GeoMultiPolygon

newtype GeoLine Source

Constructors

GeoLine
Fields _unGeoLine :: LineString GeoPositionWithoutCRS

Instances

Eq GeoLine
Show GeoLine
ToJSON GeoLine
FromJSON GeoLine

newtype GeoMultiLine Source

Constructors

GeoMultiLine
Fields _unGeoMultiLine :: [LineString GeoPositionWithoutCRS]

Instances

Eq GeoMultiLine
Show GeoMultiLine
ToJSON GeoMultiLine
FromJSON GeoMultiLine

splitGeoMultiLine :: GeoMultiLine -> [GeoLine] Source

Split GeoMultiLine coordinates into multiple GeoLines

mergeGeoLines :: [GeoLine] -> GeoMultiLine Source

Merge multiple GeoLines into one GeoMultiLine

data GeospatialGeometry Source

See section 2.1 Geometry Objects in the GeoJSON Spec.

Constructors

NoGeometry
Point GeoPoint
MultiPoint GeoMultiPoint
Polygon GeoPolygon
MultiPolygon GeoMultiPolygon
Line GeoLine
MultiLine GeoMultiLine
Collection [GeospatialGeometry]

Instances

Eq GeospatialGeometry
Show GeospatialGeometry
ToJSON GeospatialGeometry	encodes and Geometry Objects to GeoJSON (refer to source to see the values for the test values) `>>>` `A.encode NoGeometry`"null" `>>>` `(A.decode . A.encode) lShapedPoly == Just lShapedPoly`True `>>>` `(A.decode . A.encode) emptyPoly == Just emptyPoly`True `>>>` `(A.decode . A.encode) emptyMultiPoly == Just emptyMultiPoly`True `>>>` `(A.decode . A.encode) singleLineMultiLine == Just singleLineMultiLine`True `>>>` `(A.decode . A.encode) multiLine == Just multiLine`True `>>>` `(A.decode . A.encode) emptyCollection == Just emptyCollection`True `>>>` `(A.decode . A.encode) bigassCollection == Just bigassCollection`True
FromJSON GeospatialGeometry	encodes and decodes Geometry Objects to and from GeoJSON (refer to source to see the values for the test values) `>>>` `decode' lShapedPolyJSON == Just lShapedPoly`True `>>>` `decode' emptyPolyJSON == Just emptyPoly`True `>>>` `decode' emptyMultiPolyJSON == Just emptyMultiPoly`True `>>>` `decode' singleLineMultiLineJSON == Just singleLineMultiLine`True `>>>` `decode' multiLineJSON == Just multiLine`True `>>>` `decode' emptyCollectionJSON == Just emptyCollection`True `>>>` `decode' bigassCollectionJSON == Just bigassCollection`True Aeson doesnt decode "null" into `Null` unfortunately decode' "null" :: Maybe GeospatialGeometry Just NoGeometry

type Name = Text Source

type Code = Int Source

type Href = Text Source

type FormatString = Text Source

type ProjectionType = Text Source

data CRSObject Source

See Section 3 Coordinate Reference System Objects in the GeoJSON Spec NoCRS is required because no crs attribute in a GeoJSON feature is NOT the same thing as a null crs attribute. no crs value implies the default CRS, while a null CRS means you cannot assume a CRS, null will mapped to NoCRS while a non-existent attribute will be mapped to a Nothing Maybe value

Constructors

NoCRS
NamedCRS !Name
EPSG Code
LinkedCRS !Href !FormatString

Instances

Eq CRSObject
Show CRSObject
ToJSON CRSObject	encode CRS Objects to GeoJSON `>>>` `(A.decode . A.encode) testLinkCRS == Just testLinkCRS`True `>>>` `(A.decode . A.encode) testNamedCRS == Just testNamedCRS`True `>>>` `(A.decode . A.encode) testEPSG == Just testEPSG`True `>>>` `A.encode NoCRS`"null"
FromJSON CRSObject	encode and decodes CRS Objects to and from GeoJSON `>>>` `(A.decode . BS.pack) testLinkCRSJSON == Just testLinkCRS`True `>>>` `(A.decode . BS.pack) testNamedCRSJSON == Just testNamedCRS`True `>>>` `(A.decode . BS.pack) testEPSGJSON == Just testEPSG`True Aeson doesnt decode "null" to `Null` unfortunately (A.decode . BS.pack) "null" == Just NoCRS True

type FeatureID = Text Source

type BoundingBoxWithoutCRS = [Double] Source

See Section 4 Bounding Boxes of the GeoJSON spec, The length of the list/array must be 2*n where n is the dimensionality of the position type for the CRS with min values first followed by the max values, wich both the min/max sets following the same axis order as the CRS, e.g for WGS84: minLongitude, minLatitude, maxLongitude, maxLatitude The spec mentions that it can be part of a geometry object too but doesnt give an example, This implementation will ignore bboxes on Geometry objects, they can be added if required.

data GeoFeature a Source

See Section 2.2 Feature Objects of the GeoJSON spec. Parameterised on the property type

Constructors

GeoFeature
Fields _bbox :: Maybe BoundingBoxWithoutCRS _geometry :: GeospatialGeometry _properties :: a _featureId :: Maybe FeatureID

Instances

Eq a => Eq (GeoFeature a)
Show a => Show (GeoFeature a)
ToJSON a => ToJSON (GeoFeature a)	encodes Feature objects to and from GeoJSON `>>>` `(A.decode . A.encode) bigFeature == Just bigFeature`True `>>>` `(A.decode . A.encode) featureWithNoProperties == Just featureWithNoProperties`True `>>>` `(A.decode . A.encode) featureWithNoId == Just featureWithNoId`True `>>>` `(A.decode . A.encode) featureWithNoBBox == Just featureWithNoBBox`True `>>>` `(A.decode . A.encode) featureWithNoGeometry == Just featureWithNoGeometry`True
FromJSON a => FromJSON (GeoFeature a)	decodes Feature objects to and from GeoJSON `>>>` `decode' bigFeatureJSON == Just bigFeature`True `>>>` `decode' featureWithNoPropertiesJSON == Just featureWithNoProperties`True `>>>` `decode' featureWithNoIdJSON == Just featureWithNoId`True `>>>` `decode' featureWithNoBBoxJSON == Just featureWithNoBBox`True `>>>` `decode' featureWithNoGeometryJSON == Just featureWithNoGeometry`True

data GeoFeatureCollection a Source

See Section 2.3 Feature Collection Objects of the GeoJSON spec

Constructors

GeoFeatureCollection
Fields _boundingbox :: Maybe BoundingBoxWithoutCRS _geofeatures :: [GeoFeature a]

Instances

Eq a => Eq (GeoFeatureCollection a)
Show a => Show (GeoFeatureCollection a)
ToJSON a => ToJSON (GeoFeatureCollection a)	Encodes FeatureCollection objects to and from GeoJSON `>>>` `(A.decode . A.encode) bigAssFeatureCollection == Just bigAssFeatureCollection`True `>>>` `(A.decode . A.encode) bigAssFeatureCollectionWithNoBBox == Just bigAssFeatureCollectionWithNoBBox`True `>>>` `(A.decode . A.encode) emptyFeatureCollectionWithBBox == Just emptyFeatureCollectionWithBBox`True `>>>` `(A.decode . A.encode) emptyFeatureCollection == Just emptyFeatureCollection`True
FromJSON a => FromJSON (GeoFeatureCollection a)	Decodes FeatureCollection objects to and from GeoJSON `>>>` `decode' bigAssFeatureCollectionJSON == Just bigAssFeatureCollection`True `>>>` `decode' bigAssFeatureCollectionWithNoBBoxJSON == Just bigAssFeatureCollectionWithNoBBox`True `>>>` `decode' emptyFeatureCollectionWithBBoxJSON == Just emptyFeatureCollectionWithBBox`True `>>>` `decode' emptyFeatureCollectionJSON == Just emptyFeatureCollection`True

Functions

stripCRSFromPosition :: GeoPosition -> GeoPositionWithoutCRS Source

the GeoPosition is a bit special in that when you convert it to GeoJSON, it will lose the CRS info attached to it and cannot be read back in from the GeoJSON. Hence it is ineligible for the FromJSON type class, so this function will strip it down to a GeoPositionWithoutCRS, which is eligible

defaultCRS :: CRSObject Source

The default CRS according to Section 3 Coordinate Reference System Objects is WGS84 which I believe, from http://spatialreference.org/ref/epsg/4326/ which translates to this in JSON: http://spatialreference.org/ref/epsg/4326/json/) is represented thus: