Netgraph is a graphically oriented client-server application for searching in linguistically annotated treebanks. The query language of Netgraph is simple and intuitive, yet powerful enough for treebanks with complex annotations schemes. The primary purpose of Netgraph is searching in the Prague Dependency Treebank 2.0, nevertheless it can be used for other treebanks as well.
System for querying annotated treebanks in PML format. The querying uses it own query language with graphical representation. It has two different implementations (SQL and Perl) and several clients (TrEd, browser-based, command line interface).