Geospatial analysis software has a few prominent strains:

Esri & other closed-source, proprietary libraries
Open source libraries in the lineage of JTS

Python

Shapely is a friendly Python binding to GEOS
geopandas is a layer on top of Shapely and Fiona for PostGIS-like tasks

C++

GEOS is a port of JTS to C++

JavaScript

jsts is a port of JTS to JavaScript

Java

JTS

Go

gogeos is a Go binding to GEOS
go.geo is a pure-Go implementation of some geometry operations and primitives

Postgres

PostGIS provides geospatial operations within the Postgres database. Advanced operations rely on GEOS.