Max Egenhofer VL'96: IEEE Symposium on Visual Languages, Boulder, CO,
M. Burnett and W. Citrin (eds.), pp. 60-67, September 1996.
Abstract
Today's methods for interacting with geographic information
systems (GISs) and geographic databases are primarily aspatial, as
they require users to deal with geographic data primarily through
alphanumeric command languages. Currently, spatial querying is done
by typing a command in some spatial query language, such as an
extended version of SQL, or by selecting the same or a similar
syntax from pull-down menus. Such spatial querying is a tedious
process, because it often requires extensive training in the use of
the particular query language, and forces users to translate a
spatial image they may have in their mind into a non-spatial
language. Graphical user interfaces provide only little improvement
for such query languages, because they use the same type of syntax
and grammar as the typed languages, and they only release users
from remembering the particular syntax. To overcome this conceptual
gap, we propose Spatial-Query-by-Sketch, a sketch-based GIS user
interface that focuses on specifying spatial relations by drawing
them. It uses a more intuitive style of interaction with spatial
data that is made possible by the advent of pen-based user
interfaces and the increased interest in Mobile Computing. Rather
than expressing a spatial query in lexical terms, users sketch a
query in Spatial-Query-by-Sketch. This query style supports more
directly human spatial thinking. This is critical, because users
frequently have an image-like representation in their minds when
they query about spatial configurations. Rather than forcing users
to express such situations in some (semi)-formal or natural
language, it is a major step towards the successful use of spatial
information systems if users are allowed to draw a sketch of the
image they have in their mind, in order to retrieve the spatial
data of interest. This paper introduces the fundamental concepts of
Spatial-Query-by-Sketch, provides examples of typical interactions,
and discusses query-processing strategies.
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Max Egenhofer