A lot of the developers in the Hasura GraphQL Engine community use PostGIS, the popular spatial database extension for Postgres, for their apps, and it was only natural for them to expect first-class support for PostGIS topology operators like
ST_DWithin, etc. in Hasura’s GraphQL API. We are very pleased to announce the availability of native support for these operators as boolean GraphQL operators!
Using PostGIS topology operators in GraphQL
Let’s say you want to fetch a list of popular landmarks within a district/borough. In your database schema you have a table called
landmarks (a list of popular locations, with a column of type
location) and you need to search landmarks that are within a polygon (how you may model a district/borough). This is how you can now implement this search in a query using PostGIS’
ST_Within operator as a boolean GraphQL operator in the
You’ll have to pass the variable as
JSON (GeoJSON ) representation of geometry values as shown below:
You can use these operators in
List of supported PostGIS topology operators
The following is a list of all supported topology operators:
We are all ears!
We are huge fans of the PostGIS extension and very excited to contribute to the experience for developers using both PostGIS and GraphQL Engine. We'd love to hear your thoughts on this release - please do try it out and let us know how we can further improve our PostGIS support.