LostGIS

Types

TPV

create type TPV as (
    -- position
    geom     geometry(point, 3857),
    accuracy float,
    -- velocity
    heading  float,
    speed    float,
    -- time
    ts       timestamptz,
    -- helpers
    source   text,
    osm_id   bigint
);

Functions

coslat

Get latitude cosine. Works on projected geometries too.

function coslat(geometry) returns float

coslat (tpv)

Get cosine from latitude.

function coslat(tpv) returns float

Direct calculation of cos(lat) in 3857 without reprojecting it to 4326. Used following expression coslat = cos(asin(tanh(Y / 6378137))).

median

Aggregate function for getting of median

aggregate median( anyelement )

project_position

Get new position for given tpv and new timestamp.

function project_position(TPV, timestamptz) returns TPV

Calculate new position based on speed and heading from given tpv.

ST_AnglesEqual

Comparison of two angles

function ST_AnglesEqual(
    angle1 float,
    angle2 float,
    oneway boolean,
    delta  float default pi() / 4
) returns boolean

ST_AnglesEqualD

Comparison of two angles in degrees.

function ST_AnglesEqualD(
    angle1 float,
    angle2 float,
    oneway boolean,
    delta  float default 45
) returns boolean

ST_Fast_Real_Buffer.sql

It gets buffer in real meters, in contrast to ST_Buffer operating in projection units.

function ST_Fast_Real_Buffer(
    geom geometry, radius float,
    buffer_style_parameters text default ''
) returns geometry

ST_Fast_Real_Length.sql

It gets length in real meters, in contrast to ST_Length operating in projection units.

function ST_Fast_Real_Length(
    geom geometry
) returns double precision

ST_FilterSmallRings.sql

Leaves only large rings in polygon geometry. Useful for map generalization.

function ST_FilterSmallRings(
    geom     geometry,
    min_area float default 0
) returns geometry

ST_GridCell.sql

Get the geometry of rectangular cell of grid.

function ST_GridCell(
    point geometry,
    grid_size float default 500
) returns geometry

Useful for binning point datasets.

ST_LargestSubPolygon.sql

Leave a single polygon from a multipolygon geometry.

function ST_LargestSubPolygon(
    geom geometry
) returns geometry

Useful for map generalization.

ST_LineAngleAtPoint.sql

Given a line and a point at it, find the azimuth of segment the point is closest to.

function ST_LineAngleAtPoint(
    point geometry,
    line  geometry,
    delta float default 1
) returns float

ST_RealOffsetCurve.sql

Return an offset line at a given distance and side from an input line. Radius is in signed value meters.

function ST_RealOffsetCurve(
    geom geometry,
    radius float,
    buffer_style_parameters text default ''
) returns geometry

ST_Safe_Difference.sql

Replacement for ST_Difference, automatically repairing invalid geometries (see also ST_Safe_Repair). 

function ST_Safe_Difference(
    geom_a           geometry,
    geom_b           geometry default null,
    message          text default '[unspecified]',
    grid_granularity double precision default 1
) returns geometry

Also ST_Safe_Difference(geom, null) = geom, which is useful in aggregations.

ST_Safe_Intersection.sql

Replacement for ST_Intersection, automatically repairing invalid geometries (see also ST_Safe_Repair).

function ST_Safe_Intersection(
    geom_a           geometry,
    geom_b           geometry default null,
    message          text default '[unspecified]',
    grid_granularity double precision default 1
) returns geometry

ST_Safe_Repair.sql

Function that tries hard to get a valid geometry out of any geometry.

function ST_Safe_Repair(
    geom    geometry,
    message text default '[unspecified]'
) returns geometry

ST_TimeLineMerge.sql

Sew together an array of segments of track, where (x,y,z) is mapped to (x,y,timestamp).

function ST_TimeLineMerge(
    geoms geometry ( linestringz ) []
) returns setof geometry ( linestringz )