Geography.VectorTile.Geometry

Geometries

Types

class Geometry g where

Any classical type considered a GIS "geometry". These must be able to convert between an encodable list of Commands.

Minimal complete definition

fromCommands, toCommands

Methods

fromCommands :: [Command] -> Either Text (Vector g)

toCommands :: Vector g -> [Command]

Instances

Geometry Polygon

A valid Feature of polygons must contain at least one sequence of:

An Exterior Ring, followed by 0 or more Interior Rings.

Any Ring must have a MoveTo with a count of 1, a single LineTo with a count of at least 2, and a single ClosePath command.

Performs no sanity checks for malformed Interior Rings.

Methods

fromCommands :: [Command] -> Either Text (Vector Polygon)

toCommands :: Vector Polygon -> [Command]

Geometry LineString

A valid Feature of linestrings must contain pairs of:

A MoveTo with a count of 1, followed by one LineTo command with a count greater than 0.

Methods

fromCommands :: [Command] -> Either Text (Vector LineString)

toCommands :: Vector LineString -> [Command]

Geometry Point

A valid Feature of points must contain a single MoveTo command with a count greater than 0.

Methods

fromCommands :: [Command] -> Either Text (Vector Point)

toCommands :: Vector Point -> [Command]

type Point = (Int, Int)

Points in space. Using "Record Pattern Synonyms" here allows us to treat Point like a normal ADT, while its implementation remains an unboxed (Int,Int).

newtype LineString

newtype compiles away to expose only the Vector of unboxed Points at runtime.

Constructors

LineString

Fields

• lsPoints :: Vector Point

Instances

Eq LineString

Methods

(==) :: LineString -> LineString -> Bool

(/=) :: LineString -> LineString -> Bool

Show LineString

Methods

showsPrec :: Int -> LineString -> ShowS

show :: LineString -> String

showList :: [LineString] -> ShowS

Generic LineString

Associated Types

type Rep LineString :: * -> *

Methods

from :: LineString -> Rep LineString x

to :: Rep LineString x -> LineString

NFData LineString

Methods

rnf :: LineString -> ()

Geometry LineString

A valid Feature of linestrings must contain pairs of:

A MoveTo with a count of 1, followed by one LineTo command with a count greater than 0.

Methods

fromCommands :: [Command] -> Either Text (Vector LineString)

toCommands :: Vector LineString -> [Command]

Geom LineString

Methods

geomType :: LineString -> GeomType

type Rep LineString

type Rep LineString = D1 (MetaData "LineString" "Geography.VectorTile.Geometry" "vectortiles-1.0.0-9253U2nfEGPHQq8Yl4euFw" True) (C1 (MetaCons "LineString" PrefixI True) (S1 (MetaSel (Just Symbol "lsPoints") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (Vector Point))))

data Polygon

A polygon aware of its interior rings.

Constructors

Polygon

Fields

• polyPoints :: Vector Point
• inner :: Vector Polygon

Instances

Eq Polygon

Methods

(==) :: Polygon -> Polygon -> Bool

(/=) :: Polygon -> Polygon -> Bool

Show Polygon

Methods

showsPrec :: Int -> Polygon -> ShowS

show :: Polygon -> String

showList :: [Polygon] -> ShowS

Generic Polygon

Associated Types

type Rep Polygon :: * -> *

Methods

from :: Polygon -> Rep Polygon x

to :: Rep Polygon x -> Polygon

NFData Polygon

Methods

rnf :: Polygon -> ()

Geometry Polygon

A valid Feature of polygons must contain at least one sequence of:

An Exterior Ring, followed by 0 or more Interior Rings.

Any Ring must have a MoveTo with a count of 1, a single LineTo with a count of at least 2, and a single ClosePath command.

Performs no sanity checks for malformed Interior Rings.

Methods

fromCommands :: [Command] -> Either Text (Vector Polygon)

toCommands :: Vector Polygon -> [Command]

Geom Polygon

Methods

geomType :: Polygon -> GeomType

type Rep Polygon

type Rep Polygon = D1 (MetaData "Polygon" "Geography.VectorTile.Geometry" "vectortiles-1.0.0-9253U2nfEGPHQq8Yl4euFw" False) (C1 (MetaCons "Polygon" PrefixI True) ((:*:) (S1 (MetaSel (Just Symbol "polyPoints") NoSourceUnpackedness NoSourceStrictness DecidedStrict) (Rec0 (Vector Point))) (S1 (MetaSel (Just Symbol "inner") NoSourceUnpackedness NoSourceStrictness DecidedStrict) (Rec0 (Vector Polygon)))))

Operations

area :: Polygon -> Float

The area of a Polygon is the difference between the areas of its outer ring and inner rings.

surveyor :: Vector Point -> Float

The surveyor's formula for calculating the area of a Polygon. If the value reported here is negative, then the Polygon should be considered an Interior Ring.

Assumption: The Vector given has at least 4 Points.

distance :: Point -> Point -> Float

Euclidean distance.

Commands

data Command

The possible commands, and the values they hold.

Constructors

MoveTo (Vector (Int, Int))

LineTo (Vector (Int, Int))

ClosePath

Instances

Eq Command

Methods

(==) :: Command -> Command -> Bool

(/=) :: Command -> Command -> Bool

Show Command

Methods

showsPrec :: Int -> Command -> ShowS

show :: Command -> String

showList :: [Command] -> ShowS

commands :: [Word32] -> Either Text [Command]

Attempt to parse a list of Command/Parameter integers, as defined here:

https://github.com/mapbox/vector-tile-spec/tree/master/2.1#43-geometry-encoding

uncommands :: [Command] -> [Word32]

Convert a list of parsed Commands back into their original Command and Z-encoded Parameter integer forms.

Z-Encoding

zig :: Int -> Word32

Z-encode a 64-bit Int.

unzig :: Word32 -> Int

Decode a Z-encoded Word32 into a 64-bit Int.

Orphan instances

Monoid Point

Points are just vectors in R2, and thus form a Vector space.

Methods

mempty :: Point

mappend :: Point -> Point -> Point

mconcat :: [Point] -> Point