constructors
This module contains functions that create geographies from coordinates or already existing geographies.
ST_BEZIERSPLINE
carto.ST_BEZIERSPLINE(geog [, resolution] [, sharpness])
Description
Takes a line and returns a curved version by applying a Bezier spline algorithm.
geog
: GEOGRAPHY
input LineString.
resolution
(optional): INT
time in milliseconds between points. By default resolution
is 10000
.
sharpness
(optional): DOUBLE
a measure of how curvy the path should be between splines. By default sharpness
is 0.85
.
Return type
GEOGRAPHY
Examples
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SELECT 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 ], ...
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SELECT 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 ], ...
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1
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SELECT 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 ], ...
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ST_MAKEELLIPSE
carto.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 default angle
is 0
.
units
(optional): STRING
units of length, the supported options are: miles, kilometers, and degrees. By default units
is kilometers
.
steps
(optional): INT
number of steps. By default steps
is 64
.
Return type
GEOGRAPHY
Examples
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SELECT carto.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3);
-- { "coordinates": [ [ [ -73.87922034627275, 40.6643 ], [ -73.88056149301754, 40.67000644486112 ], ...
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SELECT carto.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30);
-- { "coordinates": [ [ [ -73.88715365786175, 40.68678300909311 ], [ -73.89207802212195, 40.691215338152176 ], ...
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SELECT carto.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30, 'miles');
-- { "coordinates": [ [ [ -73.85585757866869, 40.700482895785946 ], [ -73.8637839804274, 40.70761511598624 ], ...
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SELECT carto.ST_MAKEELLIPSE(ST_Point(-73.9385,40.6643), 5, 3, -30, 'miles', 80);
-- { "coordinates": [ [ [ -73.85585757866869, 40.700482895785946 ], [ -73.86194538052666, 40.70635901954343 ], ...
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ST_MAKEENVELOPE
carto.ST_MAKEENVELOPE(xmin, ymin, xma, 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
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SELECT carto.ST_MAKEENVELOPE(0,0,1,1);
-- { "coordinates": [ [ [ 0, 0 ], [ 0, 1 ], [ 1, 1 ], [ 1, 0 ], [ 0, 0 ] ] ], "type": "Polygon" }
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ST_TILEENVELOPE
carto.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
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SELECT carto.ST_TILEENVELOPE(10,384,368);
-- {"coordinates": [[[-45,45.08903556483103], [-45, 44.840290651397986], ...
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