Towards the end of last year, the T-MAPY company completed a project for the Regional Development Agency of the Plzen Region named Information System on an Area in the Plzen Region and Bavaria (preliminary study). The results of the project enhanced GIS of the Plzen Regional Authority with a new map project and data.

Project’s objectives

The project was primarily aimed to prepare a uniform, medium scale reference map that covers an area spanning international border with the Plzen Region on the Czech side of the border and the two Bavarian administrative regions, Upper Palatinate and Lower Bavaria, on the German side.

The study’s yet another goal was to examine the possibility of linking thematic data. We selected the nature protection to be the pilot thematic sphere.

Project description

The project was divided into three stages: analyze, design, implement. This structure is also reflected in the text of the study that was being created. During the research of the existing solutions to link datasets in the analyze stage, we came to the conclusion that the issues are not of a trivial kind and that they have never been dealt with in a satisfactory way.

Basic datasets selected:

• reference data
• ZABAGED (Plzen Region)
• ATKIS (German equivalent of ZABAGED)
• thematic data
• o Dataset layers of Nature Protection (Plzen Region)
• o FIS-Natur (Bavarian Nature Protection IS).

The design stage goal was to select methods and propose procedures to solve the data relationship/linkage issues between ZABAGEB and ATKIS from different points of view:

Common coordinate system: o ATKIS data were delivered in the DHDN (Deutches Hauptdreiecknetz)) coordinate system. The first issue was to select a common coordinate system (S-JTSK) and suitable transformation equations to compile the state border area data. The average distance difference of international border did not exceed 5 meters. But in some localities, the difference reached nearly 50 meters (for instance, in case of the Rozvadov border crossing). Manual corrections were necessary in 80 cases along 200 kilometers of the state border line.

ZABAGED and ATKIS state border discrepancy at Rozvadov (47 m difference)

Common state border data transformation and assuring the continuity of important cross-border lines: o The challenge of the following stage consisted in resolving the geometric continuity of the state border area down to 0 meters tolerance/level, in other words without any overlaps and gaps – the task also included resolving the continuity of important cross-border lines (such as roads, railway tracks, watercourses, power lines).To accomplish this, we created so called "resulting state borderline over the orthophoto" and the state border was drawn up from ZABAGED and ATKIS. Non-residual TSP (Thin Plate Spline) transformation was used.

ZABAGED and ATKIS state border discrepancy and non-corresponding railway line (4.2 meters difference)

• Attribute relationship of data models:
• To achieve a uniform visualization and geometric linkage of data, it was necessary to establish which objects in data models correspond with each other, and which data have no counterpart.
• Uniform visualization of datasets
• The visualization of data was based on the ZABAGED4MS technology and was complemented with characteristics present solely in ATKIS data.
• Web map application
• o To achieve the closest visualization results possible, we selected ArcMap Server (a component of ArcIMS) to be our map server. T-MapServer was utilized as the user-map server interface.
• o The MXD map project contains nearly 400 layers and, in the next phase, we are planning its optimalization so that the work with the project can be more efficient.

During the implementation process, we verified and modified the design stage procedures right on the job and selected methods to achieve the geometric uniformity of the reference and thematic data at the resulting state border. We have also obtained good quality outputs in the attribute relationship and individual visualization spheres.

Project results

The highlights on project’s results are available at: http://intermap.plzensky-kraj.cz. text of the study applications that visualize vector data in the approximate volume of 1.5 GB!
	The detail of the geometric continuity of watercourses within the state border area – before and after the TSP transformation.

Samples from the web map application

Relationship of ZABAGED and ATKIS reference data within the Bayerisch Eisenstein and Zelezna Ruda townships area (1 : 15 000)	The ZABAGED and ATKIS reference data combined with the Nature Protection and FIS-Natur thematic data (scale 1 : 250 000)

Cooperation with a university

The geometric continuity issue was resolved in cooperation with Do. Ing. Valav Cada’s team at the Department of Geomathematics, School of Applied Sciences, West Bohemia University in Plzen.

Software

ESRI technologies of the 9.1 version (ArcGIS, ArcSDE, ArcMap Server, ArcObjects, geodatabase…) were employed to resolve the GIS issues. To do the TPS transformation of data, we created the ArcGIS module program. The results of data linkage and visualization are published in the T-MapServer application environment.

Further potential

During the work on the study, we came up with many ideas and directions that could not be included in the project because of the time-schedule and financial reasons. We are considering to continue with the study within another, upcoming project.