Converting spatial buffer operation from Azure SQL to Amazon Redshift

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Migrating and handling spatial buffer transformations between Azure SQL and Amazon Redshift

Details

When migrating spatial buffer operations from Azure SQL to Redshift, here are the key conversions and considerations:

  1. Syntax Conversion:

    From Azure:

    geography::Point(Latitude, Longitude, 4326).STBuffer(distance_in_meters)

    To Redshift:

    ST_Buffer(
        ST_SetSRID(ST_Point(Longitude, Latitude), 4326),
        distance_in_degrees
    )
  2. Distance Unit Conversion: In order to convert to degrees in Redshift use the below conversion formula. This will handle the geographic calculation,

    distance_in_degrees = (distance_in_meters / 1000) / (111.32 * COS(RADIANS(Latitude)))
  3. Required Modifications:

    1. Convert distance from meters to degrees

Example:

From Azure:

geography::Point(47.6097, -122.3331, 4326).STBuffer(5000)

To Redshift:

ST_Buffer(
    ST_SetSRID(ST_Point(-122.3331, 47.6097), 4326),
    5.0 / (111.32 * COS(RADIANS(47.6097)))
)

Test the converted queries thoroughly, as slight variations in buffer calculations might occur due to different geodetic implementations.

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published 24 days ago60 views