International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
An interactive map server with a central geo data server as
backbone becomes necessary if current information from spatial
analyses has to visualised via Internet. Here one can find
monolithic proprietary architectures, which contain the geo data
servers and the necessary map server as part of the standard GI
systems family. A nearly unrestricted number of WWW-based
GI clients can be constructed based on this map server
philosophy offering the appropriate functionality to the users.
The OpenGIS Consortium (OGC) defined a web mapping
specification (WMS) and web feature specification (WFS) to
allow interoperability between systems of different vendors.
Already most of the well-known GIS-vendors support this
standard and deliver product lines based on this standard. Thus
data of different GIS services can be merged into any
Internet/Intranet portal.
«| Scripts Map =
| Progr. | | Server | | Meta |
DB | |
Client
statically
—
Se
Terminal
Fig. 1: Overview of architectures by Internet-GIS
Herewith one can construct simple information system as well
as fairly complex technical system (Strobl, Blaschke,
Griesebner, 2002). Distributed GIS solutions are specified by
the OpenGIS and realised for example with Common Object
Request broker architecture (CORBA).
4. CONCEPT AND DEVELOPMENT OF THE
INTERNET-GIS FOR THE COUNTY
ADMINISTRATION
4.1 Introduction
By legislation in Germany the cadastral office of a municipality
or county has to set up a digital cadastral data set. For this land
registration process a more or less unique approach is foreseen
for whole Germany. The graphical data set is called ALK
(Automatisierte Licgenschaftskarte, Automated real estate
map), it handles spatial and graphical data of parcels, buildings
and other geodetic information in a true-to-scale representation
usually in map scales between 1:1.000 to 1:2.500. The tabular
digital property data are called ALB (Automatisiertes
Liegenschaftsbuch, Automated real estate tables) covering
ownership, parcel size, land usage and other legal rights related
to parcels and buildings as attributes. The content and the
structure of the local GIS solutions should be finished until
2007 for the whole federal state of Mecklenburg-Western
Pomerania. By legislation it is also defined that other spatial
information systems created in municipalities and counties such
as environmental information systems or planning information
systems (see Bill, 1999b) should be based on these so-called
geo base data sets such as ALK and ALB. This is the reason
why district administrations, which acquire and update these
144
base data, are increasingly on the search for solutions, how to
publish and deliver these data as easy and uncomplicated as
possible to other users. Cadastral offices are placing themselves
in the role of data service providers. This would create positive
impacts on the geo-data market in general. In the district
administration many data have a common spatial reference. The
linkage of these data would result in a new quality for the
access to the data. It would improve the data management, e.g.
by reducing redundancies. A further substantial aspect linking
the data of the public administration with the spatial reference
data, represented by ALK, ALB, and the coordinated addresses
from the residents’ registration office, is the improvement of the
topicality of the data.
In the context of a diploma thesis and some R&D-projects an
Internet-GIS prototype was developed for the county
administration in Bad Doberan, a district surrounding the city of
Rostock in the northern part of Germany. We used the UMN
map server and PHP MapScript, an open source product. On the
basis of the developed prototype the opportunities of the
application of an Internet-GIS should be investigated. The
principle steps and the experiences gained with this system are
described in the following chapters.
4.2 Data collection and conversion
In the first phase of the realisation of this Internet-GIS for the
county administration all information, which should be
published via Internet, need to be converted. This is valid for
the ALK and ALB and other data sets on the county level. The
ALK data, which are captured with the GIS DAVID, are stored
in a data base at the cadastral office of the county. For safety
reasons in the Internet solution the ALK data should be
published as a copy of the original data set. Thus it was easier
to convert the data into the well-known ESRI shape format
which is supported by the UMN Map Server. The ALB data are
maintained and stored in the computing centre at the federal
level of Mecklenburg-Western Pomerania. Usually they are
delivered online to the user based on his individual query. The
transfer of the ALB data from the WLDG file into a data base
format was done. This concept needed modifications because in
future ALK and ALB will be merged together to one common
geo-information system. This is called ALKIS (Automatisiertes
Liegenschaftskataster-Informationssystem, ^ Automated real
estate information system). This makes it necessary that the
data are stored and delivered at one place. For our prototype we
realized this with a copy of the original data, both for the
graphic and the attribute data. This process of preparing the
data sets for publishing via Internet has to be done at the official
place, it may be automated and can be done on a periodical base
e.g. each night, each week, each month dependent on the
updating cycle and the users demands. The solution achieved
should give different users access to the common data base,
both on the county level and the municipality level. Additional
data sets might be integrated: e.g. at the county level
environmental data and at the municipality level zoning plans.
In many municipalities zoning plans are still available in an
analogue format, i.e. it was necessary to scan and georeference
these maps. The map server delivers these maps as
georeferenced raster data sets. In addition we integrated digital
orthophotos captured with our low-cost aerial flight system
PFIFF. In the prototypical implementation we prepared all these
different data sets for a small municipality named Elmenhorst-
Lichtenhagen, just to analyse performance and user acceptance
issues.
Currently many data sets have to be specifically prepared and
converted for the purpose of publication via Internet. In future
Intt
wit
tec
con
con
mei
4.3
The
of t
HT
Jav:
sep:
leve
fun
The
map
adm
be u
scale
Top
Ther
map
the c
they
feasi
GIS
inter
redu
avoi
offic
or de
also |
for tl
From
of thi
menu
