Various spatial data sets of high quality and homogeneity allow a higher level of multidisciplinary research. The study is aimed at providing a clearer understanding of the technical and semantic aspects of the quality of historical maps, especially with respect to positional errors, through the georeferencing process. Georeferencing the system of historical map sheets with high precision over a large area is not easily incorporated into the less complicated standardised process. Significant problems may occur in rough mountainous regions, especially as many of the areas were not accessed at that time and therefore not surveyed. The standard process of georeferencing comprises mosaicking of singular map sheets to a seamless map, referencing with identical points, and applying an appropriate transformation method. The quality of georeferenced maps is assessed with statistical and visual parameters. The enhanced process additionally integrates descriptive (textual) information about the mapping processes, derivative georeferenced data sets as land use analysis, and Monte Carlo simulations. This approach allows a more detailed understanding of the quality and consequently improves a georeferencing process for any historical data sets. The First Military Survey maps of the Habsburg Monarchy (Josephine survey), produced between 1763 and 1787, were used as study data and the rugged Julian Alps of the Triglav National Park in Slovenia were employed as the study area.
Preliminary attempts to georeference maps of early twentieth century made by the Military Geographic Institute (IGM, the Italian geodetic agency) for the city of Rome and its surroundings, reported residual errors larger than errors observed on similar maps. Previous studies carried out on one or two century older maps of the same area, showed similar or even smaller errors (Baiocchi and Lelo 2005).Six sheets of the “City of Rome and its surroundings” map in scale 1:5 000 dated 1908 have been studied. The identified errors can be referred to the different system of geodetic projection and geodetic datum or to the derivation of some details from maps at smaller scale, but in this case historic documents seem to suggest a different explanation.Parameters useful to perform the transformation of the geodetic systems used in historical maps to modern systems are not known; for this reason until now the various attempts of georeferencing maps of this type were based on collimation of points recognizable on modern cartographies such as corners of historical buildings. This method has often given unsatisfactory results; therefore it was decided to proceed by determining the parameters for the transformation of geodetic datum.The history of geodetic systems used in Italy at the beginning of the 20th century is complex and, in the past, this has led some researcher to misinterpretations. For this reason a full explanation of geodetic systems used in Italy in this period is reported below. Since the parameters of the projection used for the maps in our case study are not known for sure, the reprojection was considered the only way for a correct georeferencing.
Lake Balaton is located in the Pannonian Basin, Hungary (46°50′ N, 17°50′ E), and is characterized by its large area (594 km
) and very shallow water depth (avg. 3.5 meters). The main tributary is the Zala River, which enters the western bay, and the only outlet is the Sió River in the East.Sámuel Krieger conducted the first known survey focusing on Lake Balaton in 1776. The original purpose of Sámuel Krieger’s work was to illustrate his plans of draining and canalizing Lake Balaton. This map indicates several proposed canals and bathymetric contour lines according to a water level drop of 1, 2, or 3.33 Viennese fathoms (1 Viennese fathom = 1.89 meters). The map also shows settlements, land use and relief. Krieger measured water input from tributaries, documented the water level fluctuations of the lake, and summed his results in the “Descriptio”, a document with several tables of data and a written description of Lake Balaton, the Sió River, and the possible benefits of his plan of draining the lake.Almost 90 years later, the water level was lowered by approximately 1 meter in 1863, cutting off large marsh areas from the water system of the lake. The first bathymetric map was surveyed in 1895 after the lake was partially drained. The bathymetric survey was carried out with the purpose of estimating the water volume held by the lake. Understanding water balance was important for flood control after the Sió Canal and lock was built in 1863. Water depth was measured in 2884 points, along sections near the shore, and scattered points in areas of low relief. Depth was measured with a sounding line or pole. Horizontal positions were measured optically from military triangulation points, and elevations were leveled from a network of benchmarks placed for this survey. Distances were measured in fathoms but elevations were measured in meters for better accuracy. Reprojection of the scanned map was possible, but we had to correct minor errors by triangulation. Surviving benchmarks, depicted buildings and railway bridges were used as control points. The resulting map was used to create a Digital Elevation Model of the lake floor for investigating sedimentation processes.
Methods for georeferencing and GIS applications of the maps and plans from the 16th century until 1990 are described. The results of georeferencing — derivatives of historical maps, show a high value and potential of usability for the studies of urban areas — for historical issues, and for more comprehensive planning solutions allowing better development and policy. The applicability of the georeferenced historical maps was explored according to time series analysis. The studied were the applications for the urban area of Ljubljana, Slovenia case study: observing the continuous changing of the river course of Ljubljanica river and railway network.
The Müller’s map of Bohemia is one of the most important maps of Czech history. In the last couple of years this map has been scanned and analysed a few times. Spatial position of the map symbols is usually compared with current situation. Using this method we can explore changes of the landscape through the ages. The crucial problem of this approach is georeferencing raster image into some well defined coordinate system. The best way to handle that problem is using ground control points (GCPs) and appropriate type of spatial transformation. The problem of choosing the best set of GCPs is not solved correctly yet. Usually well identifiable points are used depending on the researcher’s meaning. Proposed method is based on creating full vector data model of the map. Having complete vector database of the map, we can test many combinations of GCPs and many types of spatial transformation. Another great advantage of vector database is the fact, that vector data are easier to be analysed (e.g. spatial overlays, proximity analyses, or spatial statistics) in GIS software. As we wanted to make a new thorough analysis of the Müller’s map of Bohemia, we decided to create its full vector data model. Methods of creating the model are explained in this article. At the end the map was georeferenced and several spatial statistics were done.
The present paper focuses on the use of old maps and written sources in analyses of the landscape structure and husbandry in the first half of the 19th century. The studied area is situated in the Boletice Military Area in Southern Bohemia (southwest of the Czech Republic). Attention was paid in particular to the area of the former villages of Ondřejov and Chlumany. The maps of the First and the Second Military Surveys, Stable Cadastre, and forestry maps were used for the analysis, together with selected written sources. The results show that ingenious agriculture including mowing, grazing of a notable number of cattle, ploughing and forestry was once characteristic in the area. This paper presents especially the woodland structure in the area and some inconsistencies that were found on the old maps.
Lake Balaton is a large, shallow lake (area: 597 km
, average depth 3.3 m) located in Western Hungary. The valleys joining the lake hold wetlands which are of high conservation value. When the water level of the lake was lowered by more than a meter in 1863, these valleys were also partially drained. In order to investigate the original state of these wetlands and the lake, the corresponding sheets of the First Habsburg Military Survey (1783–1784) were georeferenced and interpreted. The shorelines of the wetlands were compared with present-day elevation contours to create elevation profiles of the valleys. The water level of Lake Balaton was measured by comparing the depth contour lines of the georeferenced Krieger Map (1776) to the present-day elevation model of the lake floor. The results show that the valleys can be grouped into lacustrine and fluvial types, the former characterized by low slope angles, the latter by comparable steeper slopes and water retention by vegetation. The original water level of the lake was around 106.5 meters above sea level. The connections of the valleys with the lake were evaluated and priorities for focusing conservation efforts were suggested based on the geomorphology of the region.
A method is presented in this paper for solving a practical problem: how to make georeferenced mosaic of a map series using ground control points and quadratic polynomial transformation for every individual map sheet, if we expect, that after georeferencing the edges of the transformed map sheets should fit together.To solve this problem we can use a constrained polynomial fit method. In this method we use least square adjustment to get the transformation parameters for every individual map sheets, and we define constrains, that the common edges of every two neighboring map sheet should transform similarly. Solving this equation we get the transformation parameters for every single map sheet. Using these parameters for transforming the map sheets, we get georeferenced maps, that automatically fit together in a GIS software.This method has been successfully applied for georeferencing 18 map sheets of the First Topographic Survey of the Habsburg Empire. The resulting georeferenced map has larger residual errors than the individually transformed map sheets, but in exchange for we get a seamless map mosaic, that is more accurate, than the graphically merged and transformed.
Old cartographic documents represent a valuable resource in reconstructing the natural and built environment evolution. In order to integrate such maps with recent geospatial datasets, in GIS environment, some preparatory actions need to be done. This includes scanning, color enhancement, georeferencing and reprojection. From our experience, when it comes to collections with a large number of map sheets, georeferencing is the most meticulous and time consuming process. Traditionally, this is done manually, by carefully selecting points with known coordinates. To overcome this disadvantage and to increase the rectification precision an automated procedure was created. The whole process of map sheet georeferencing is done by a specially developed tool, called “findlines”, which relays on radon transform to extract, even in degraded and noisy conditions, all the straight lines from the map graticule network. Then, by knowing the distance between the graticule lines and the relation between the map name and lower-left corner coordinates, it is possible to automatically associate real coordinates to each intersection points in the graticule. Finally, the points are used along with GDAL to rapidly georeference each map sheet. The method was first successfully tested with modern topographic maps. To evaluate the procedure with old cartographic documents we select the 1:20 000 Romanian maps collection, under Lambert-Cholesky (1916–1959) projection system, as test data. The basic map, called “Plan Director de Tragere” was drafted under 1:20 000 scale in 2 118 drawings, covering all the Romanian territory. Each map sheet is 75 cm wide and 50 cm high and has a direct relation between the name and the lower-left corner coordinates. The maps were also successfully georeferenced using the findlines utility. Depending on the selected resample method, the time needed to georeference each map sheet, using 150 control points, ranged between 3 and 15 minutes on a normal computer. That proved the method efficiency and flexibility. Any map series with a regulated graticule grid and a logical relation between the name and the spatial position can be georeferenced using this approach, without any human intervention.
Müller’s maps of Moravia and Bohemia are important parts of the cartographic and art history. They are not just beautifully and well made, but also part of the living heritage, which have been attracting the attention of people for centuries. Apart from that, they have significantly contributed to the development of cartography. Processing and cartometric analysis of these maps can open access to them and show their quality. Georeferencing significantly improves the possibilities of comparing the map with the present situation. They show the evolution of the landscape as well as that of human settlements. Moreover, publication of the map on the Internet makes it accessible to academics and to the general public. Thus they make a valuable contribution to the popularization of cartography and increase interest in maps.