Skip to content

Enhanced Accuracy for ST_Transform

Versions: 2.0.1-preview and 1.11.1

Date: August 13, 2025

The following release notes are for both 2.0.1-preview and 1.11.1.

Version 2.0.1-preview has the vectorized engine turned on per Accelerate Standard Data Operations By Up to 2x -- Preview WherobotsDB 2.0.

Customer-facing changes

We've introduced an enhancement to the ST_Transform function to significantly improve the accuracy of Coordinate Reference System (CRS) transformations.

The ST_Transform function now includes an optional AOI (Area of Interest) parameter.

By specifying an AOI, the transformation process uses a relevant subset of local grid files, resulting in more precise and reliable CRS transformations for your geospatial data.

This is especially beneficial for large-scale and high-precision mapping applications.

How it works

Previously, ST_Transform performed transformations without a specific geographic context.

With this update, you can provide an AOI as a geometric boundary.

The function then leverages this information to select the most appropriate local grid files (e.g., NTv2, NADCON) for that specific area, minimizing errors and producing a more accurate result.

Example usage

The following SQL query converts standard latitude/longitude coordinates to a local, meter-based map projection, using a defined area to achieve enhanced accuracy.

ST_Transform Enhancement Example
SELECT ST_Transform(
  geom,
  'EPSG:4326',
  'EPSG:26910',
  '{"area_of_interest": "POLYGON((-122.5 37.7, -122.3 37.7, -122.3 37.8, -122.5 37.8, -122.5 37.7))"}'
)
FROM my_table;

Explanation

The ST_Transform function converts each geometry in the geom column of my_table from one Coordinate Reference System (CRS) to another.

  • Source CRS: EPSG:4326 (WGS 84), the standard system for GPS latitude and longitude.
  • Target CRS: EPSG:26910 (NAD83 / UTM Zone 10N), a projected system used for Northern California that measures distances in meters.
  • Area of Interest (AOI): Specifies a POLYGON covering part of San Francisco. This tells the ST_Transform to use specific local data grids for this area of interest, ensuring a more precise and accurate transformation.

No breaking changes

  • There are no breaking changes in this release for WherobotsDB.
  • There are no breaking changes in this release for WherobotsAI.