constructors
CORE
This module contains functions that create new geographies from coordinates or already existing geographies.
ST_BEZIERSPLINE(geog [, resolution] [, sharpness])
Description
Takes a line and returns a curved version of it by applying a Bezier spline algorithm. Note that the resulting geography will be a LineString with additional points inserted.
geog
:GEOGRAPHY
input LineString.resolution
(optional):INT
total time in milliseconds assigned to the line. By defaultresolution
is10000
. Internal curve vertices are generated in 10 ms increments, so the maximum number of resulting points will beresolution/10
(close points may be merged resulting in less points). A higher number will increase the accuracy of the result but will increase the computation time and number of points.sharpness
(optional):DOUBLE
a measure of how curvy the path should be between splines. By defaultsharpness
is0.85
.
Return type
GEOGRAPHY
Examples
SELECT CARTO.CARTO.ST_BEZIERSPLINE(
TO_GEOGRAPHY(
'LINESTRING (-76.091308 18.427501,-76.695556 18.729501,-76.552734 19.40443,-74.61914 19.134789,-73.652343 20.07657,-73.157958 20.210656)'
)
);
-- { "coordinates": [ [ -76.091308, 18.427501 ], [ -76.09134585033101, 18.427508082543092 ], ...
SELECT CARTO.CARTO.ST_BEZIERSPLINE(
TO_GEOGRAPHY(
'LINESTRING (-76.091308 18.427501,-76.695556 18.729501,-76.552734 19.40443,-74.61914 19.134789,-73.652343 20.07657,-73.157958 20.210656)'
),
10000
);
-- { "coordinates": [ [ -76.091308, 18.427501 ], [ -76.09134585033101, 18.427508082543092 ], ...
SELECT CARTO.CARTO.ST_BEZIERSPLINE(
TO_GEOGRAPHY(
'LINESTRING (-76.091308 18.427501,-76.695556 18.729501,-76.552734 19.40443,-74.61914 19.134789,-73.652343 20.07657,-73.157958 20.210656)'
),
10000,
0.9
);
-- { "coordinates": [ [ -76.091308, 18.427501 ], [ -76.09134541990707, 18.42750717125151 ], ...
ST_MAKEELLIPSE(geog, xSemiAxis, ySemiAxis [, angle] [, units] [, steps])
Description
Takes a Point and calculates the ellipse polygon given two semi-axes expressed in variable units and steps for precision.
center
:GEOGRAPHY
center point.xSemiAxis
:DOUBLE
semi (major) axis of the ellipse along the x-axis.ySemiAxis
:DOUBLE
semi (minor) axis of the ellipse along the y-axis.angle
(optional):DOUBLE
angle of rotation (along the vertical axis), from North in decimal degrees, negative clockwise. By defaultangle
is0
.units
(optional):STRING
units of length, the supported options are: miles, kilometers, and degrees. By defaultunits
iskilometers
.steps
(optional):INT
number of steps. By defaultsteps
is64
.
Return type
GEOGRAPHY
Examples
SELECT CARTO.CARTO.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3);
-- { "coordinates": [ [ [ -73.87922034627275, 40.6643 ], [ -73.88056149301754, 40.67000644486112 ], ...
SELECT CARTO.CARTO.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30);
-- { "coordinates": [ [ [ -73.88715365786175, 40.68678300909311 ], [ -73.89207802212195, 40.691215338152176 ], ...
SELECT CARTO.CARTO.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30, 'miles');
-- { "coordinates": [ [ [ -73.85585757866869, 40.700482895785946 ], [ -73.8637839804274, 40.70761511598624 ], ...
SELECT CARTO.CARTO.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30, 'miles', 80);
-- { "coordinates": [ [ [ -73.85585757866869, 40.700482895785946 ], [ -73.86194538052666, 40.70635901954343 ], ...
Additional examples
ST_MAKEENVELOPE(xmin, ymin, xmax, ymax)
Description Creates a rectangular Polygon from the minimum and maximum values for X and Y.
xmin
:DOUBLE
minimum value for X.ymin
:DOUBLE
minimum value for Y.xmax
:DOUBLE
maximum value for X.ymax
:DOUBLE
maximum value for Y.
Return type
GEOGRAPHY
Example
SELECT CARTO.CARTO.ST_MAKEENVELOPE(0,0,1,1);
-- { "coordinates": [ [ [ 0, 0 ], [ 0, 1 ], [ 1, 1 ], [ 1, 0 ], [ 0, 0 ] ] ], "type": "Polygon" }
ST_TILEENVELOPE(zoomLevel, xTile, yTile)
Description Returns the boundary polygon of a tile given its zoom level and its X and Y indices.
zoomLevel
:INT
zoom level of the tile.xTile
:INT
X index of the tile.yTile
:INT
Y index of the tile.
Return type
GEOGRAPHY
Example
SELECT CARTO.CARTO.ST_TILEENVELOPE(10,384,368);
-- {"coordinates": [[[-45,45.08903556483103], [-45, 44.840290651397986], ...
Last modified 6mo ago