Ž .
ISPRS Journal of Photogrammetry Remote Sensing 54 1999 234–243
GeoHyp: an adaptive human interface for geologic maps and their databases
Stefanie Kubler
a,
, Agnes Voisard
b
¨ `
a
Institute for Geology, Geophysics and Geoinformatics, Free UniÕersity Berlin, Malteser Str. 74-100, D-12249 Berlin, Germany
b
Institute for Computer Science, Free UniÕersity Berlin, Takustr. 9, D-14195 Berlin, Germany Accepted 29 April 1999
Abstract
A geologic map is typically a 2D representation of 3D subsurface structures in a given area. It is based on the currently accepted geologists’ model explaining the observed phenomena and the processes that shaped them in the geologic past. For
historical reasons, this model is recorded in a geologic map with an explanatory booklet that describes the authors’ conclusions as well as relevant field observations and other data such as tectonic measurements, drill hole logs or fossil
records. Today, however, this variety of information can be better handled by converting it into digital and even hypermedial format. This necessitates the prior conception, development and implementation of a suitable geologic ‘‘hypermap model’’.
The main objective of this study is to design models and tools well-suited for the interaction between users and geologic
Ž .
hypermaps. The unique aspect of this family of applications is that users, in general, are both end-users e.g., engineers and Ž
. designers e.g., mapmakers . Objectives, concepts and methods for developing a human interface to geologic hypermaps
Ž .
have been tested using a prototype i.e., GeoHyp within the GIS environment of ArcView from ESRI. Tools to access the underlying background database via hyperlinks have been implemented, as well as functions especially developed to meet
specific geologic requirements. Tests with various types of users have shown that the prototype matches their expectations and serves as a good basis for further development. In this article, we report on our design choices for GeoHyp and the
current status of our project. q 1999 Elsevier Science B.V. All rights reserved.
Keywords: hypermap; geology; graphical user interface; GIS; databases
1. Introduction
A geologic map is based on a conceptual model concerning the geologic phenomena and the pro-
cesses, which shaped them during the Earth’s his- tory. To convey this model to the user, the map must
be accompanied by an explanatory booklet contain-
Corresponding author. E-mail: kstefzedat.fu-berlin.de
ing notes, profiles, pictures etc. Due to technical limitations, only a portion of the information avail-
able to the mapping geologist can be shown in a paper map and included in the explanations. For this
reason, significant freedom of interpretation remains with the user.
Today, in the era of digital mapping and geo- Ž
. graphic information systems GIS we have the abil-
ity to rethink the way of publishing geologic knowl- edge. It is possible to store all the background infor-
0924-2716r99r - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž
. PII: S 0 9 2 4 - 2 7 1 6 9 9 0 0 0 2 4 - 6
mation about a map in a GIS database. However, there is still no standard regarding geospatial data
modelling, storage and query. Assuming such an environment would be compliant with a query lan-
Ž .
guage such as the Standard Query Language SQL , the retrieval of the requested pieces of information
would still require experience in formulating SQL- statements. This is often unacceptable as many users
Ž .
are not experienced with SQL Egenhofer, 1992 . In addition, geologic applications require many differ-
ent types of data that should be handled by a power- ful query language.
Therefore, a suitable interface between the map user and the associated data must be found. Hyper-
medial methods are a solution to this problem as they allow consistent access to many different types
of data. Hypermaps, defined as digital maps con- nected by means of hyperlinks with background
Ž .
information Laurini and Thompson, 1992 , are cur- Ž
. rently in use for vegetation
Hu, 1999 , touristic Ž
. Ž
Kraak and Driel, 1997 and cartographic Krygier, .
1997 applications. To our knowledge, the potential use of hypermedia in geology has not yet been fully
investigated. It should be noted that geologic maps differ from topographic maps in several ways. For
example, geologic maps typically depict the spatial distribution of rock types and their relationships as
2D representations of 3D subsurface structures Ž
. Powell, 1992 . In contrast to topographic maps,
geologic maps are not only portrayals of the surface structures but also interpretations of rock-structures
under the ground. In addition, topographic maps are based on direct observations while geologic maps
also represent phenomena, which elude direct obser- vation. This means that in areas with few outcrops
new data can lead to completely new interpretations
Ž necessitating geologic map revision Nickless and
. Jackson, 1994 .
As every hyperdocument, a geologic hypermap is only useful if it is structured in a sensible manner.
Because of the various disciplines in geology, a user-specific structuring of the interface and the data
is needed. For instance, a hydrogeologist will use the map to solve questions different than those of an
economic geologist. In order to spare him or her the need to search the complete set of information, it is
necessary to provide specialised geologists with spe- cific tools and data. By means of such tools, query-
ing the map can be partly automated. This would significantly facilitate, for example, the preparation
of environmental impact assessments. A number of national organisations are working
on similar user-specified data structuring. Among them, the U.S. Geological Survey is preparing a
Ž .
model for geologic metadata Raines et al., 1998 and the Geological Survey of Canada has developed
Ž .
a database for geologic field data Brodaric, 1998 . The British Geological Survey is also very active in
Ž this field
Nickless and Jackson, 1994; Bain and .
Giles, 1997 . Requirements of geologic hypermaps go beyond
Ž those for traditional hypertext applications Voisard,
. 1998 . In particular, the various types of semantic
relationships, both at a regular and at a metadata level are very important. The underlying database
model also must be powerful enough to handle these relationships. Besides spatial dependencies, time de-
Ž .
pendencies e.g., paleographic development have to be considered by the hypermap model.
In addition, the identification or deduction of geologic features is an iterative and evolutionary
process. This means that geologic map making is often an incremental process. Based on initial obser-
vations, hypotheses are formulated which might be supported or refuted by further evidence. It is an
analytical process where the collected data can lead
Ž to re-classification or re-interpretation
Brodaric, .
1998 . This evolutionary classification may radically affect geologic map making. Hence such geologic
hypermaps also have to take into account the possi- bility of updating multidimensional data in terms of
time, space and assumptions.
Geological Surveys benefit considerably from the results of such applications. Within the framework of
the geologic hypermap project we have worked closely with the Geological Survey of Northrhine-
Ž .
Westfalia, Germany GLA NRW since the begin- ning of the project in 1996. Our hypermap approach,
known as GeoHyp, was tested in a pilot study using the 1:25,000-scale geologic map set of Brilon. This
area was surveyed between 1987 and 1992 by
Ž .
Steuerwald GLA NRW . This article is organised as follows. Section 2
reports on human-computer interaction with geologic hypermaps. In Section 3 our developed tools are
illustrated and Section 4 draws our conclusions.
2. Human-computer interaction with geologic maps
