Analytics Toolbox for BigQuery

constructors

This module contains functions that create geographies from coordinates or already existing geographies.

ST_BEZIERSPLINE

Description

Takes a line and returns a curved version by applying a Bezier spline algorithm.

• geog: GEOGRAPHY input LineString.
• resolution: INT64|NULL time in milliseconds between points. If NULL the default value 10000 is used.
• sharpness: FLOAT64|NULL a measure of how curvy the path should be between splines. If NULL the default value 0.85 is used.

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SELECT `carto-os`.carto.ST_BEZIERSPLINE(ST_GEOGFROMTEXT("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);
-- LINESTRING(-76.091308 18.427501, -76.0916216712943 ... 

ST_MAKEELLIPSE

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: FLOAT64 semi (major) axis of the ellipse along the x-axis.
• ySemiAxis: FLOAT64 semi (minor) axis of the ellipse along the y-axis.
• angle: FLOAT64|NULL angle of rotation (along the vertical axis), from North in decimal degrees, negative clockwise. If NULL the default value 0 is used.
• units: STRING|NULL units of length, the supported options are: miles, kilometers, and degrees. If NULLthe default value kilometers is used.
• steps: INT64|NULL number of steps. If NULL the default value 64 is used.

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SELECT `carto-os`.carto.ST_MAKEELLIPSE(ST_GEOGPOINT(-73.9385,40.6643), 5, 3, -30, "miles", 80);
-- POLYGON((-73.8558575786687 40.7004828957859 ... 

ST_MAKEENVELOPE

Description Creates a rectangular Polygon from the minimum and maximum values for X and Y.

• xmin: FLOAT64 minimum value for X.
• ymin: FLOAT64 minimum value for Y.
• xmax: FLOAT64 maximum value for X.
• ymax: FLOAT64 maximum value for Y.

Return type

GEOGRAPHY

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SELECT `carto-os`.carto.ST_MAKEENVELOPE(0,0,1,1);
-- POLYGON((1 0, 1 1, 0 1, 0 0, 1 0)) 

ST_TILEENVELOPE

Description Returns the boundary polygon of a tile given its zoom level and its X and Y indices.

• zoomLevel: INT64 zoom level of the tile.
• xTile: INT64 X index of the tile.
• yTile: INT64 Y index of the tile.

Return type

GEOGRAPHY

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SELECT `carto-os`.carto.ST_TILEENVELOPE(10,384,368);
-- POLYGON((-45 45.089035564831, -45 44.840290651398, -44.82421875 44.840290651398, -44.6484375 44.840290651398, -44.6484375 45.089035564831, -44.82421875 45.089035564831, -45 45.089035564831))

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 960401.