  A lot of sensor network applications are data-driven. We believe that query
is the most preferred way to discover sensor services. Normally users are
unaware of available sensors. Thus users need to pose different types of query
over the sensor network to get the desired information. Even users may need to
input more complicated queries with higher levels of aggregations, and requires
more complex interactions with the system. As the users have no prior knowledge
of the sensor data or services our aim is to develop a visual query interface
where users can feed more user friendly queries and machine can understand
those. In this paper work, we have developed an Interactive visual query
interface for the users. To accomplish this we have considered several use
cases and we have derived graphical representation of query from their text
based format for those use case scenario. We have facilitated the user by
extracting class, subclass and properties from Ontology. To do so we have
parsed OWL file in the user interface and based upon the parsed information
users build visual query. Later on we have translated the visual query
languages into SPARQL query, a machine understandable format which helps the
machine to communicate with the underlying technology.
