We have developped a WEB-GIS framework called soft-GIS.
Soft-gis has all the functionalities needed for rappresenting any kind of spatial data with complete customization of it, and allow you to directly edit data from the web.
Soft-Gis is a complete GIS solution built as a web application.

With soft-Gis you can perform complex geometries editing without any plugin.
Some features:
In the solutions sections there are some solutions already prepared for the managment of some specific domains.
It is possible to use soft-gis as a generic gis, develop its own solution or use predefined solutions.

Construction tools (line, arc, circle, intersections, mesure)

More constructions on covers layer
Using soft-Gis
Using soft-gis is very simple. You have to register and subscribe an account and start using your application with unlimited users.
User can create its own data model editing geometries, import/export data in all standard formats.