If the user selects a geographical search, he is presented 
the map in fig. 8 and can click in a point to get the names 
of the entities within a give radius from that point, 
displayed in a window. 
Clearly, during this operation, the user may zoom or pan 
on the map to have a better perception of the situation. At 
a certain zoom level, a raster image for the regional 
technical map also appears. 
Fig. 8 - Data search with geographic criteria. On the 
upper left, one may select the entity type, at the 
lower left, the list of entities around the clicked point 
Data sets satisfying the user criteria are listed on the 
screen and the user may open the related file to check if 
their content is indeed of interest before downloading 
them. 
The procedure for data submission differs, at this point, 
because only the selected entity name is displayed and 
the user is requested to fill the data description fields. He 
or she normally selects the attribute values within 
predefined sets and adds whatever additional information 
he deems necessary in the “comment” field. For 
submitting the proposal of a new station, it suffices to 
insert the name and the coordinates (in geographical or 
Gauss-Boaga coordinates, according to the Italian 
standard). 
Fig. 9 - The Administrator data checking page 
This material is stored in temporary files, waiting to be 
examined by the administrator. He is notified by e-mail of 
the arrival of new material and, opening the map, will see 
the entities to which the data are related in a different 
color (a red triangle if it is a new station). He should check 
the correctness of the data description (see fig. 9) and, if 
so, simply click on a button to let the data enter the 
system and become available for all the users. In case of 
insertion of a new station, a separate form (fig. 10) allows 
him to check the automatic relations established or add 
new ones. 
Fig. 10 - Automatic (upper right) and added (lower right) 
relations between entities (listed on the left) and a 
new station 
Finally, fig. 11 shows how the administrator controls the 
displaying of map layers. 
Fig. 11 - Administrator’s definition of map characteristics 
7. CONCLUSIONS 
The field of environmental information systems is still very 
open and a substantial contribution is expected by the use 
of map-based search engines. Many environmental data 
catalogues are in fact still searchable only by standard 
web engines, which often can found no answer (see for 
instance, the Environmental Virtual Library at 
http://www.earthsystems.org/ or the Directory of 
Information Resources of the European Environment 
Agency).