INTERNATIONAL BORDER DEMARCATION: TOPOGRAPHIC MAP SERIES ON SHORTEST DEMAND AND WITH HIGHEST QUALITY

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1 INTERNATIONAL BORDER DEMARCATION: TOPOGRAPHIC MAP SERIES ON SHORTEST DEMAND AND WITH HIGHEST QUALITY Ralf Schroth 1 and Hans-Dieter Arnold 2 1 Hansa Luftbild Group Münster, Germany and FIG International Federation of Surveyors Copenhagen, Denmark schroth@hansaluftbild.de 2 Hansa Luftbild Group Münster, Germany arnold@hansaluftbild.de ABSTRACT The paper describes several border demarcation and documentation projects on the Arabian Peninsula during the last decades. The focus will be a presentation of the general workflow of international border projects and especially the final production part will be emphasised, the digital cartography for series of large, medium and small scale topographic maps. The sources of information are up-to-date aerial images and satellite data, field verification, names collection, integration of existing map information, homogenisation of different reference systems including the generation of a new geodetic frame system. The borders mapped go through coastal plains, high mountains and large deserts. The related map scales often range from 1: to 1: For cartographers the major challenge is most probably the consistent presentation of different landscapes for maritime and land parts, densely populated areas as well as empty desert zones. This paper will deliver an insight into the exciting world of border demarcation projects and the multidisciplinary tasks to be coped with based on a long term experience of a company working in these kind of projects for more than 15 years. 1. INTRODUCTION Disputes about international borders between different sovereigns could be solved by bilateral contracts between the states involved. The United Nations accepts the agreed border line as an international boundary, if the border is exactly demarcated and described by lists of coordinates, reports and up-to-date maps at different scales. It is the solemn duty of each sovereign to settle its state borders to live in peace with its neighbouring countries. All over the world there are ongoing negotiations about the definition of provisional or preliminary border lines. In many cases there are no treaties or any other documents describing the legal situation neither there is any border demarcation existing. Therefore since the eighties of the last century the Hansa Luftbild Group specialized on this topic and is working as consultant and general contractor. The involved parties are assisted with latest technologies and standards. Although the final bilateral contract and all the legal aspects are generated by the state organizations by themselves in their own sovereignty, the organisational and technical realization is a great challenge (cf. PETRING (1998)). Very often the area of the border lines to be defined is poorly settled and quite remote with less infrastructure which causes high demands on the logistics (see chapter 2). But also the different types of terrain had to be handled in very different ways. In general the areas could be separated in coastal zones with the documentation of the sea border line, mountainous zones with some settlements but also extremely height differences. The highest mountains exceed m

2 and the valleys are steep and rough. And the third zone can be characterized as big gravel and sand plains, with enormous sand dunes of more than 200 m height. An overview can be seen at figure 1. Figure 1: Area of the border demarcations on a length of more than km In the following the work process on border demarcation is described while the emphasis is focused on the special cartographic aspects of the documentation whereas in very short time several hundreds of topographical maps had to be produced. The preparation phases of long lasting negotiations about technical specifications, treaties and general terms and conditions including reconnaissance can be found in SCHROTH et al. (2002). The careful handling of this conceptual work is a major step to the success of the project. 2. WORK PROCESS 2.1 Project Organisation and Logistics The project duration on an average of about 4 years, the coordination of more than 10 involved companies and the controlling of a turnover of several hundred of millions of dollars demand on a strong and effective project organisation. Therefore a steering group of project managers were installed. The principle function of the project management group can be seen in figure 2 (cf. MEHLBREUER (2004)). This group is the technical and administrative interface between the client and the contractor. It is a team of specialists from the general contractor working at the headquarters, in both involved states and on site during the demarcation phase. The major functions are defined as coordination with the client, coordination of the suppliers, scheduling, overall reporting and quality control. The project management is assisted by scientists from different disciplines and a team of financials like controllers, accountants and auditors. The legal aspects are covered by international lawyers. On the clients side both states established so called border offices which are controlled by different ministries. Out of this a team of specialists forming the Joint Technical Committee which are coordinating in a common way the

3 projects. For special tasks like surveying, construction or cartography joint teams of specialist are grouped equally from both states. Client State A State B Joint Technical Committee Technical Field Teams State A State B Joint Working Teams Contractor Project Management Group Sciences Finances Internal Resources External Resources Figure 2: Project organisation (steering group) Besides the project organisation a real challenge was all the necessary logistics to run the projects on site. For the geodetic survey and the construction of the border monuments more than 500 people were working in the area. Camps for housing, maintenance of equipment, storage of materials and local offices had been installed (see figure 3). These camps were moving along side the border line to keep the distances between the construction areas and the base not to far. Because of the lack of roads and tracks, new gravel tracks were constructed. Thousands of tons of materials, especially water, had to be brought on site. In the mountainous areas most of the deliverables were brought in by helicopters (figure 4). All the vehicles were equipped with GPS receivers, radio or satellite communication systems. The adverse living conditions like temperatures up to 56 Celsius caused several problems for the humans and the equipment. So health and safety was an important issue and only very few serious accidents at work happened on site. Figure 3: Camp in mountainous area Figure 3: Use of helicopters

4 2.2 Geodetic Base Networks The first step of a border demarcation is the establishment of a geodetic network. As the border line is defined by border monuments and markers, these points should be precise and accurate. Therefore along the border area a first order geodetic network with links to the national networks were built up. Several datum points were observed and processed together with International GPS Service-Stations. As geodetic datum the ITRF (International Terrestrial Reference Frame) were selected. The overall accuracies of the network and the border points were in a range of a few millimetres. Absolute reference of the height values to the mean sea level of each country was done by connecting the base survey network to national bench marks. To determine the mean sea level height differences for the height survey, a combination of GPS-measurements and astro-levelling was applied. 2.3 Survey and Construction In a second step after the first order network, a densification network has been established. Close to the border line temporary GPS-points were surveyed and used for the stake out of the border points which were described in the bilateral treaties by their geographic coordinates referred to the World Geodetic System 1984 (WGS 84). The border points, the network densification points and the GPS-points were again measured with GPS-techniques. The stake out of the different border points was done by conventional surveying methods with total stations (figure 5) and it was permanently checked over the whole construction time till the final establishment of the theodolite mounting plate on the top of the pillars defining the central reference point. All different kind of border points like first and second order points or witness points were constructed in situ. Due to the different geological and topographic situation and for reasons of stability a pre-fabrication of the monuments was not applied. The physical installation of the border points started with drilling holes down to the specified depth and the consecutive installation of stainless steal pipes. These steel pipes anchor each monument to the ground. Different types of border points requested its own particular design due to point class and geological situation. A typical first order point can be seen at figure 6. Figure 5: Survey of border point during construction Figure 6: Final border point with signalisation 2.4 Aerial and Satellite Imageries For the documentation of the border area medium and small scale map series had to be produced (see chapter 3). Most of the map series are so called orthophoto maps, i.e. the topographic information is composed with geo-referenced and rectified image data. For the medium scale map series aerial images at a scale of 1: with ground resolution of about 25 cm were produced. For the small scales Landsat TM sceneries were take. High resolution satellite images were not chosen because of the demand of high accuracy for stereo restitution, especially for the DTM measurements. The georeferencing of the image data was done by ground control points, in-flight differential GPS and INS information and integrated sensor orientation by adjustment methods.

5 2.5 Photogrammetric Stereo Restitution Based on a GIS data base model all visible planimetric features like houses, roads, tracks, etc. has been captured. As the topographic information was used to produce different map scales as well for the GIS the completeness and richness of the content had the highest priority. Necessary generalization procedures were transferred to the cartographic process. The same rules applied to the height measurements. In the very steep mountainous terrain contour lines were directly stereo plotted. In the flat and homogeneous terrain raster points and break- and form-lines were measured for the determination of the DTM. All images were processed digitally and out of the DTM and the image information seamless digital orthophotos as mosaics were produced. 3. CARTOGRAPHY 3.1 Field Verification In order to ensure accuracy, consistency and quality of the border maps, supplementary information is required to complete the photogrammetric stereo restitution. For this purpose, the photogrammetrically captured details had to be verified in the terrain. During the process of field editing, erroneous details were corrected and features not present on the photogrammetric manuscripts had to be added to the existing digital photogrammetric data sets to transform them into a foundation for cartographic products. The field verification comprised a physical inspection of the area covered the photogrammetric plots. A legend listed specified features and instructions for compilation, which had to be applied to the features to be verified. If possible also orthophoto mosaics were made available providing a basis for orientation in the field and for comparison with the found terrain situation. Features derived from existing source maps and from other documents were also verified and added to the existing photogrammetric data sets. All features had to be checked and verified by visual inspection and/or appropriate survey methods. Features were added or corrected by methods that ensured horizontal and/or vertical positioning within defined limits of the mapping accuracy criteria. GPS surveying methods were applied for automatic placement and addition of surveyed features to the relevant photogrammetric data sets in subsequent production steps. If appropriate, simple construction methods were applied, they were drawn on overlays to the photogrammetric plots. The field verification mission requested a maximum employment from the performing staff. Major parts of the project areas were because of the extreme topography difficult to access. In the mountainous areas even the all-terrain vehicles had problems to get to places to be verified. As long as possible the camps for the civil works were used as bases to get water, provisions and fuel. All the time the field verification crews were equipped with satellite telephones to keep in touch with the base camp. To meet the time table s deadlines the field work had to be carried out whenever requested. As a consequence field verification took place in winter in mountainous terrain and in summer in the dessert. Following the end of each field verification field crews performed the post-processing of the information collected in the field. Post-processing consisted of editing the photogrammetric plots by introducing a colour code system classifying all corrections for further processing. In addition all digital survey data was provided as output on paper listings that were attached to the sheets as part of the deliverables to all parties concerned. Once corrections or additions were shown on the plots, the digital photogrammetric data base was amended and updated in subsequent production steps within the further cartographic work procedure to match the new situation. 3.2 Collection of Geographical Names In addition to the verification and completion of topographic features in the field, collection of geographical names had to be undertaken. These names were collected by crews working simultaneously during the field verification missions in close co-operation with government authorities and local guides. All border maps were bilingual Arabic and English. The original Arabic name of a feature as well as its Romanised transliteration had to be collected and shown on the map face. For general orientation and for the verification of available names, maps of each country s national map series were used as a source of basic information. The names collection was based on plots showing all photogrammetrically captured details relevant to collection of geographical names and orthophoto mosaics. Any previously unrecorded name

6 collected in co-operation with local guides had to be pointed out by the relevant features (point, line and area features) and named. The names were recorded on tape and registered in a list, together with identifying information such as coordinates and feature type. The geographical location of each feature was determined using hand-held GPS receivers. Recording the names onto tape was utilised in order to avoid pronunciation mistakes and to facilitate transliteration. Each name had to be recorded three times and whenever possible by different speakers. The Arabic spelling of a name was discussed on the spot amongst the local inhabitants until a consensus was reached. Preliminary transliteration from Arabic to the Roman alphabet was performed immediately in the field. Existing names, that were not known to local guides, but shown on existing maps, were omitted from the subsequent mapping process. In order to prepare the preliminary name manuscripts, a separate set of plots at the relevant scales was produced showing for each sheet separately, the location of features for which names had been collected. To define the place of area names, area features were marked by their surrounding outline. Finally a list with the Arabic name, its Romanised version after transliteration and the specification for the font type and font size to be used for naming each feature prepared. The transliteration demanded for all projects a special attention due to different local rules in the countries involved. For typesetting different techniques were applied ranging from state-of-the-art software supported typing and placing up to manual handwriting by calligraphers in combination with photographic reproduction and mounting the films with the names on a transparent names overlay in former projects. In areas with a high density of names the double number of names in two languages sometimes became a problem for the presentation of names in bilingual maps due to limited space. The names compete for space among themselves, but also with other cartographic features or the orthophoto they cover. This conflict can only be solved by minimizing the number of names or, if this is not possible, accepting a reduced readability of the covered topographic features or the orthophoto background. Another special aspect to be taken into account in the production of bilingual border maps is the placement of the two corresponding names and their relative position to represent the named feature. In both languages the map user should be able to identify the same named topographic feature using only the name in one language. Such features can be very small, but it is also possible, that a feature extends over one or more than one map sheet. For this reason all Arabic names and its Romanised version after transliteration including the typesetting (font type, font size and spacing) and calligraphy of names had to be approved by the clients in lists and maps. 3.3 Cartographic Procedures The aim of cartographic compilation was to assemble the final contents of each map sheet coming from different sources, giving all map details their final size and location and to generate for each map sheet a set of high quality lithographic colour separates to derive the required films for printing. Therefore a number of preparatory different digital cartographic works had to be done such as the definition of the sheet line systems, the preparation of style sheets, the generation of text styles for map faces and the definition of the data structure. Among these preparatory steps the definition of the data structure was the most important one and had to take into account several aspects. The data structure had to make sure, that the integration of data provided from the different sources such as photogrammetry, field verification and names collection and others into the cartographic workflow was possible. Furthermore the data structure should enable a data conversion to different CAD- and GIS-systems at a later stage. Finally the information to run the rasterisation process for the production of lithographic colour separates had to be considered, when designing this data structure. The data structure was designed for Bentley s CAD Software MicroStation, which was used for cartographic editing and compilation. This software was supported by a number of project specific taylorized applications. The regular cartographic work requested the application of a number of production steps to the data such as preparing the vector data for the cartographic process, editing of the field verification results, cartographic compilation, geographic names compilation, map generalisation and digital lithographic process.

7 The organisation of all these work steps proofed to be a task requesting a detailed planning and strong project management. Under the condition of extremely short production times (e.g. about 200 map sheets in less than 2 years) the cartographic work had to be done for a high number of very often overlaying or adjacent map sheets at the same time or at least in very short subsequent periods. The respective larger scale maps had to be completed before the overlaying smaller scale maps could be finalized to assure the consistency of information in the maps. These conditions resulted in a quite rigid production scheme. Figure 7 shows an example of a sheet line system with the location of maps from 4 different scales. Additionally three further smaller map series had to be considered, which are not shown in this figure. Figure 7: Sheet line system Figure 8: Symbolisation of steep slopes A special cartographic solution was requested for the height representation of cliffy mountainous regions, when the contour line intervals were too small for steep slopes. In such cases the contour lines plotted by stereo plotting can not be separated in their representation in the maps. The contour lines get in touch with each other or even overlay themselves. In such cases the contour line interval had to be extended, which means contour lines in the maps were taken out. If this did not solve the problem, a special symbolisation for the cliffy and steep slopes were produced. In different projects special slope symbols were used (see figure 8). Finally a major challenge in terms of cartographic compilation was the design of a common similar appearance for all border maps. The situation shown in the maps ranged from off-shore areas, coastal plains, rocky mountains and desserts. Densely populated areas with many cartographic features and very often diversified topography had to be balanced with areas almost without cartographic feature and barely changing topography in the dessert. The management of this very complex task was in the hand of experienced cartographers. It ranged from specifying the radiometric processing of the orthophoto mosaic, compiling the map contents and the printing of the maps in the printing shop and is a proof of the complexity of such projects. Figure 9 gives an overview about the digital lithographic process, which has been used for the production of films for offset printing (cf. STOLL (2004)). The processing of raster files was done with Intergraph s MapPublisher software in order to compile the final output for the printing. The MapPublisher process performed an essential processing on the data, e.g. defining print priorities, masking, combining, screening and separating. The output were raster files (LSR) for each map in each colour layer that will be used for the production of lithographic separates. Furthermore, colour composite files (CMYK-TIFF) were generated for proof plots, showing for each map sheet the combined data of the colour separates in one file. These composites were used in the process of checking and reviewing. For film production a Map Setter6000 was used. 3.4 Printing With regard to map production, the final product of the borderline demarcation projects were multi-colour printed line maps mostly with orthophoto/satellite image background at the different scales. These maps document the newly demarcated border line between the two countries, featuring the positions of border points established in the course of the project along with other topographic details. Map printing was performed by offset printing onto map paper. The paper used for map printing had to exhibit optimum properties such as dimensional stability, smoothness and firmness of the paper surface as well as elasticity of paper in order to withstand the pressure when running through the

8 printing machine and also during later use. Consequently only a high quality technical paper could used for map printing requesting large formats. The selected base stock was no regular made. A special order had to be placed to produce the necessary amount of paper for map printing.. In total, up to some 26,000 kg of paper were required to print the requested number of copies of each border map. This quantity also included the amounts that were needed for making ready the machine for printing and checking of catch sheets prior to each print run. At the end 13,000kg had to be shipped by airfreight to their final destination. Figure 9: Digital lithographic process Taking into consideration the sheet size of the different border map series, the printing of maps had to be separated according to the capacity of accessible printing machines. Separation into the two jobs thus had to be done according to the 2 format classes 72cm x 104cm and 102cm x 142cm. Especially the larger format class requested experienced production experts to guarantee the specified quality in terms of registration accuracy and colour saturation. The largest map size coming up in the production of border maps was 132cm x 78cm. Such large map formats using almost the whole format of a printing machine are not very common in map printing. The machine operator of a printing machine processing such paper sizes must have experience in handling such formats. A further special solution was selected for the printing of border maps by taking the decision to use solid tone colours. Usually offset printing knows inks act by subtractive colour, in multi-colour printing the inks must be sufficiently transparent to allow maximum reflection of light from the paper surface. However, the spectral characteristics of most process inks were considered far from ideal for this type of map printing. In addition to difficulties in maintaining the selected colour, constantly exact matching of the subtractive colour separates could not be guaranteed. Since a clean impression constitutes the premier requirement in representing a major part of map contents as line work, Hansa Luftbild decided to switch to printing in solid tones. With seven colour representation in the map face and map margin the use of solid tones allowed for overprinting in all situations and for more freedom in the selection of colour series and colour balance. Furthermore, this enabled the application of the decorative colour gold for the heraldic figure requested in one project. The definition of colours for representation of the map content was based on the Pantone Matching System (PMS). 4. CONCLUSION To produce a border map series is really something particularly challenging. Probably nowhere else in the world map series in such a variety of different scales ranging from large scales to small scales can be found in a single project to be realized in only a few years. In the border demarcation projects executed by Hansa Luftbild cartographic information along the linear feature border are presented in up to 8 different scales. Originally those maps were only intended to serve as visualization of legal treaties defining a border between countries by a list of co-ordinates. But after their completion the maps with the topography mapped along the borderline were also used to develop the border areas infrastructure.

9 Under scientific aspects the cartography of such maps does not only follow common cartographic rules, but also taking into account individual client requests. A very challenging aspect of the production of a border map series is the integration of contributions coming from so many different scientific disciplines. The most important technical ones are civil engineering, geodesy, photogrammetry and remote sensing and of course cartography and printing. But also commercial, financial and legal aspects had to be managed by the respective experts. The job to integrate the various contributions is managed by a general contractor using the variety of project management techniques. REFERENCES MEHLBREUER, A., 2004: Dream and Reality of Intercultural Project Management. Proceedings of ISPRS Congress, Istanbul PETRING, J., 1998: Land Boundary Demarcation and Management A contractor s Point of View. IBRU Workshop: Land Boundary Demarcation and Management, Durham UK SCHROTH, R. and ARNOLD, H.D., 2002: Demarcation of International Border Lines. Proceedings of the FIG Congress 2002, Washington D.C. STOLL, H., 2004: Map Production and Pre Press. Proceedings of Geospatial World, Miami FL

10 BIOGRAPHY OF THE PRESENTING AUTHOR Ralf Schroth, born in Berlin in the year 1953, studied Geodesy and Surveying from 1972 up to 1977 at the University of Stuttgart. After the probationary period for the national surveying administration in the Land Baden-Wuerttemberg he got his degree as legal surveyor in He worked as a scientific assistant at the Institute for Photogrammetry at the University of Stuttgart under the leadership of Prof. Fritz Ackermann till There he was active in the fields of research and development, giving lectures in Photogrammetry and adjustment theory, software development for aerial triangulation and photo-reproduction. In 1985 obtaining the degree of Doktor-Ingenieur. Since 1984 he is working with the company Hansa Luftbild in Muenster, where he is now acting as managing director of Hansa Luftbild Sensorik und Photogrammetrie GmbH and member of the board of the Hansa Luftbild Group. Ralf Schroth has more than 20 years experiences in business administration and management, project management, Photogrammetry und Geo-Information systems. He introduced different GI-systems at the Hansa Luftbild Group and was in charge of them. Already in 1988 he was announced as a member of the management board at Hansa Luftbild GmbH and co-founded an international group of companies. He was also responsible for general contracting projects on the Arabian Peninsula. He is board member in several affiliated companies in Germany and abroad. Since 1991 he is a lecturer at the University of Hanover for business administration and management for surveying engineers. In 1997 he got the appointment as honorary Professor from the University of Hanover. Since 2004 he is also lecturer at the Institute of Geomatics at the Polytechnic University of Barcelona. Ralf Schroth is Vice President of the International Federation of Surveyors (FIG). He published more than 40 technical and scientific papers and gave more than 50 presentations in the field of Photogrammetry, GIS and management.