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Historical Maps (historical + map)
Selected AbstractsUsing a historical map as a baseline in a land-cover change study of northeast TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 2009Lowe Börjeson Abstract Vegetation data in an early 20th century map from northern Tanzania are presented and discussed for its potential of expanding the analytical time-frame in studies of land-use and land-cover change. The starting point is that much research on land-use and land-cover change suffers from a time-frame bias, caused by limitations in remote sensing data. At the same time, the use of historical maps as a complementary data-set is rather insignificant. Can information in historical maps be used to extend the baseline in land-use and land-cover change studies? The historical context of the vegetation data is evaluated, and as an illustration of its potential for interdisciplinary research on land-cover and ecosystems change, a section of the map is juxtaposed with a recent pollen record specifically addressing the impact of a ,large infrequent disturbance' (LID) event at the end of the 19th century. It is concluded that the vegetation data in the map are not likely to be reflecting an extreme situation due to the LID event. Finally, the historical vegetation data were visually compared with a national 1995 land-cover data set, illustrating the possibility of using the map data as a baseline in land-cover change studies. [source] An improved method for determination of Holocene coastline changes around two ancient settlements in southern Anatolia: a geoarchaeological approach to historical land degradation studiesLAND DEGRADATION AND DEVELOPMENT, Issue 4 2003Y. Bal Abstract Two well-known ancient sites in southern Anatolia were selected to investigate and quantify the impact of historical land degradation on the Mediterranean coast of Turkey. These sites are the Luwian settlements of Kelenderis (modern Ayd,nc,k) and nearby Nagidos (Bozyaz,), both in Mersin Province and both occupied since around 4000,BP. Changes in local climatic conditions over this period have produced variations in the rates of fluvial transport of sediment/soil from the hinterland into the relevant deltaic regions, thus influencing rates of coastal progradation and aggradation. In addition, both eustatic and neotectonic movements have contributed to deltaic subsidence and/or hinterland uplift, with consequential impact on coastal evolution (positive or negative). The novel geoarchaeological methodology adopted in this study involves the creation of a graphical archive from detailed and standardised measurements taken from rectified mono- and stereoscopic aerial photographs. These archival data were then integrated with data from several types of historical map and field measurements in order to develop a geographical information system (GIS) database that could be interrogated, enabling graphical models of past coastal change to be constructed and calculations then made of the coastal configurations at successive historical periods. These calculations reveal that over the past 6000 years there has been only limited erosion/degradation in the karstic hinterland supplying the sediment to these two study sites (contrary to some previous statements concerning the high degradation risk of Mediterranean karst terrains). Furthermore, rates of progradation in each delta appear to have become diminished or even reversed in the past several decades as a result of both natural and anthropogenic factors. The precise contribution of neotectonic movements in this seismically active zone remains unquantified and is a topic requiring further interdisciplinary study. Copyright © 2003 John Wiley & Sons, Ltd. [source] Big diameter tunnelling beneath low rock cover.GEOMECHANICS AND TUNNELLING, Issue 3 2009Bau eines Großtunnels unter geringer Felsüberdeckung Abstract The Clem Jones Tunnel (former North-South Bypass Tunnel) is the first project to get underway as part of Brisbane's transport plan which aims to improve the urban road network. The total length to be excavated is 6.8 km which includes 4.8 km of driven tunnel and associated road connections. Construction commenced in August 2006 with project completion targeted well before the contractual completion date of October 2010. Due to the local geology, in particular the hard Brisbane tuff and Neranleigh-Fernvale formation a combination of tunnel excavation methods are used. The majority of the tunnel is excavated by two tunnel boring machines in rock having a compressive strength of between 80 and 150 MPa. Ten roadheaders are excavating the remaining tunnels such as ramps, access tunnels, cross passages and merges. A major challenge arose during the planning of the initial mainline excavation underneath the Royal National Association Showground in Bowen Hills. This section contains low rock cover and historical maps indicate that the Showground is located within a former topographic depression (alluvial valley) where a creek once flowed through. Due to traffic merge design requirements, both TBM and roadheader excavation methods were required to be used in this challenging geological profile. The answer was to stabilise the alluvium above both TBM section tunnels from the surface prior to excavation and to operate the TBM in single shield mode with immediate grouting of annular void from the tail shield. In addition, the roadheader section of tunnel required additional support by spiles and canopy tubes installed from the tunnel face. Der Clem Jones Tunnel (ehemals North South Bypass Tunnel) ist das erste in Angriff genommene Projekt des Brisbane-Transportplans. Dieser Plan hat das Ziel, das städtische Straßennetzwerk zu verbessern. Insgesamt wird eine Strecke von 6,8 km aufgefahren, einschließlich 4,8 km bergmännische Tunnel und zugehörige Straßenanbindungen. Die Bauarbeiten begannen im August 2006, und die Fertigstellung des Projekts ist deutlich vor dem vertraglich vereinbarten Fertigstellungstermin im Oktober 2010 geplant. Der größte Teil der Tunnel wird durch zwei Tunnelbohrmaschinen im Hartgestein mit einer Druckfestigkeit zwischen 80 und 150 MPa ausgebrochen. Zehn Teilschnittmaschinen fahren die übrigen Tunnel wie Rampen, Zugangstunnel, Querschläge und Verbindungen auf. Eine große Herausforderung ergab sich während der Planung des Haupttunnelvortriebs unter dem Ausstellungsgelände der Royal National Association in Bowen Hills. Dieses Gebiet besitzt eine geringe Felsüberdeckung, und aus historischen Karten weiß man, dass das Ausstellungsgelände in einer ehemaligen topografischen Senke (alluviales Tal) liegt, durch die früher ein Bach floss. Aufgrund von Verkehrsplanungsanforderungen war es notwendig, sowohl Tunnelbohrmaschinen als auch Teilschnittmaschinen in dieser schwierigen geologischen Situation zu verwenden. Die Lösung bestand darin, das Schwemmland über beiden TBMTunneln von oben her zu stabilisieren und die Tunnelbohrmaschine in der Einfachschildbetriebsart zu fahren, wobei der Ringspalt vom Schildschwanz aus verpresst wird. Die durch Teilschnittmaschinen ausgebrochenen Tunnel mussten außerdem zusätzlich durch Spieße und eine Rohrschirmsicherung gestützt werden. [source] Long-term land-cover changes in the Belgian Ardennes (1775,1929): model-based reconstruction vs. historical mapsGLOBAL CHANGE BIOLOGY, Issue 7 2002C. C. Petit Abstract Understanding long-term human-environment interactions requires historical reconstruction of past land-cover changes. The objective of this study is to reconstruct past land-use and land-cover changes in a rural municipality of the Belgian Ardennes over the last 250 years. Two approaches were compared. The first approach produced backward projections based on a mechanistic model which computes the demand for different land uses under the assumption of an equilibrium between the production and consumption of resources. The second approach involved using a series of historical maps to extract directly land-use areas. A stochastic Markov chain model was also used to project backward missing land-cover data in the time series. The consistency between the results obtained with the different approaches suggests that land-use area can be successfully reconstructed on the basis of the mechanistic model, under conditions of a subsistence farming system and a closed economy. Land-use/cover changes in the Belgian Ardennes from 1775 to 1929 were more driven by the interventionist measures of the Belgian government and by technological progress than by the ,pressure' of the growing population and livestock. Thanks to agricultural intensification, a decrease in land under human use was supporting increasing human and livestock populations from 1846 to 1880. Reforestation has accelerated since the mid-19th century. This case study illustrates the highly dynamic and non-linear character of land-use change trajectories over long time periods and their strong interactions with the history of societies. [source] Digitization and geo-referencing of botanical distribution mapsJOURNAL OF BIOGEOGRAPHY, Issue 7 2002Christian A. Schölzel Aim In many fields of research, valuable information is stored in atlases and maps which are only available as printed media. Scientists who are interested in computational analysis often seek to digitize the data to make it accessible for numerical calculations. In this paper, an approach using the example of digitizing distribution maps taken from plant-taxonomic atlases is described. For this purpose, a software tool has been built for application in the Sonderforschungsbereich 350 `Interactions between and Modelling of Continental Geosystems' at the University of Bonn. Its functionality has to be simple in use and capable of transforming fields drawn on geographical maps into grid data even where the type of map projection is unknown. Location As an example, plant distributions over Europe and Asia have been digitized. Methods To achieve this aim through an objective statistical analysis, the local deterministic approximation has been used for geo-referencing. Results For this reason the development of a new software tool was required. Although there is a large market for related software from Geographical Information Systems (GIS), none of the available GIS-programs appeared to be capable of geo-referencing maps with unidentified projections. Rather than to give a product comparison, this paper aims on the methodology and mathematical formalism. Main conclusions The developed algorithm is a handy tool to capture data from maps based on obscure projections. Valuable historical maps, which are problematic for standard GIS-programs, can be made accessible for modern research work. [source] Forest plant species richness in small, fragmented mixed deciduous forest patches: the role of area, time and dispersal limitationJOURNAL OF BIOGEOGRAPHY, Issue 6 2001Hans Jacquemyn Aim The research aimed to investigate how plant species richness of small, fragmented forest patches changes over time. Also interactions between time and area were studied in relation to species richness. Finally, the relative importance of plant dispersal limitation on the process of species accumulation was examined by investigating how species were distributed within a regional landscape. Location Mixed deciduous forest patches in central Belgium. Methods The land use history of a region of 80 km2 was reconstructed using nine historical maps dating from 1775 to 1991. Within a central area of 42 km2, 241 forest patches were surveyed for presence/absence of 203 species predominantly occurring in forests. Aggregation of species within this region was estimated using a Monte Carlo simulation. Spatial and temporal patterns of species richness were investigated by both regression and analysis of variance (ANOVA). Results Fifty-one of 103 species showed significant spatial aggregation patterns, suggesting severe dispersal limitation. Species richness significantly increased with age. However, the effects of time on species richness could not be separated from area and area and time clearly interacted. Slopes of regression equations for species number on area and patch age were shown to be significantly interrelated. Main conclusions Area and time cannot be treated independently as predictors of plant species richness. Dispersal proved to be important in structuring local forest plant community composition, contrary to most other studies that have investigated local forest plant community structure. The processes of forest succession and species accumulation are controlled by both local and regional processes. More studies focusing on the regional factors determining local community composition are needed in order to fully understand the process of forest plant community assembly. [source] Using a historical map as a baseline in a land-cover change study of northeast TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 2009Lowe Börjeson Abstract Vegetation data in an early 20th century map from northern Tanzania are presented and discussed for its potential of expanding the analytical time-frame in studies of land-use and land-cover change. The starting point is that much research on land-use and land-cover change suffers from a time-frame bias, caused by limitations in remote sensing data. At the same time, the use of historical maps as a complementary data-set is rather insignificant. Can information in historical maps be used to extend the baseline in land-use and land-cover change studies? The historical context of the vegetation data is evaluated, and as an illustration of its potential for interdisciplinary research on land-cover and ecosystems change, a section of the map is juxtaposed with a recent pollen record specifically addressing the impact of a ,large infrequent disturbance' (LID) event at the end of the 19th century. It is concluded that the vegetation data in the map are not likely to be reflecting an extreme situation due to the LID event. Finally, the historical vegetation data were visually compared with a national 1995 land-cover data set, illustrating the possibility of using the map data as a baseline in land-cover change studies. [source] Long-term post-fire changes in the northeastern boreal forest of QuebecJOURNAL OF VEGETATION SCIENCE, Issue 6 2000Louis De Grandpré Abstract. Natural dynamics in the boreal forest is influenced by disturbances. Fire recurrence affects community development and landscape diversity. Forest development was studied in the northeastern boreal forest of Quebec. The objective was to describe succession following fire and to assess the factors related to the changes in forest composition and structure. The study area is located in northeastern Quebec, 50 km north of Baie-Comeau. We used the forest inventory data gathered by the Ministère des Ressources naturelles du Québec (MRNQ). In circular plots of 400 m2, the diameter at breast height (DBH) of all stems of tree species greater than 10 cm was recorded and in 40 m2 subplots, stems smaller than 10 cm were measured. A total of 380 plots were sampled in an area of 6000 km2. The fire history reconstruction was done based on historical maps, old aerial photographs and field sampling. A time-since-fire class, a deposit type, slope, slope aspect and altitude were attributed to each plot. Each plot was also described according to species richness and size structure characteristics. Traces of recent disturbance were also recorded in each plot. Changes in forest composition were described using ordination analyses (NMDS and CCA) and correlated with the explanatory variables. Two successional pathways were observed in the area and characterized by the early dominance of intolerant hardwood species or Picea mariana. With time elapsed since the last fire, composition converged towards either Picea mariana, Abies balsamea or a mixture of both species and the size structure of the coniferous dominated stands got more irregular. The environmental conditions varied between stands and explained part of the variability in composition. Their effect tended to decrease with increasing time elapsed since fire, as canopy composition was getting more similar. Gaps may be important to control forest dynamics in old successional communities. [source] | |||||||||||||