[OSGeo-Discuss] An interesting article about software licensing in the non-open source geospatial world

[Venkatesh Raghavan]

Frank

Frank Warmerdam wrote:
...
> 
> Building on software distributed under well understood and relatively
> unrestrictive open source licenses can help a great deal.

Could you let me know what would the
"relatively unrestrictive open source licenses"
be.