Régnauld de Lannoy de Bissy’s Nineteenth Century Map of Africa at a Scale of 1∶2 000 000

Cartographic projects of national importance are often only reported on in local journals which are published in the language of the author or mapping organisation. Owing to this, important maps and map series often stay unknown outside their country of origin. A case in point is the important Carte d’Afrique on a scale of 1∶2?000?000 which, during the last decades of the nineteenth century, was compiled by the French army officer Captain Richard de Régnauld de Lannoy de Bissy. The map made an enormous contribution to the history of cartography of Africa with regard to not only the discovery and exploration of the continent, but also the expansion of colonial control and the political rivalry between European powers. It was an impressive project to be executed by one man and at the time guaranteed a prominent position for the author in geographic and cartographic circles worldwide. Although afterwards superceded by many more accurate maps, Lannoy de Bissy’s map to date remains a lasting witness to the mapping of the ‘dark continent’ and of the fragile, hesitating progress made during the search for geographical knowledge before the advent of aerial photography and satellite imagery.     

The scheme for the database building and updating of 1∶10 000 digital elevation models

［1］Balce A E. Determination of optimum sampling interval in grid digital elevation models (DEM) data acquisition.Photogrammetric Engineering and Remote Sensing,1987,531:323～330 ［2］Li Z L. Sampling strategy and accuracy assessment for digital terrain modelling: [Ph. D Thesis]. UK: University of Glasgow, 1990 ［3］Li Z L. Variation of the accuracy of digital terrain models with sampling interval. Photogrammetric Record, 1992,14:113～128 ［4］Li Z L. A comparative study of the accuracy of digital terrain models(DTMs) based on various data models. ISPRS Journal of Photogrammetry and Renote Sensing,1994,49(1):2～11 ［5］Li Z L. Scale issues in geographic information science. In:Proceeding of International Workshop on Dynamic and Multi-dimensional GIS. Hong Kong, 1997. 143～158 ［6］SISM. Specification of geospatial data (Provisional) for 1:10 000 digital elevation models. The Standard Institute of Surveying and Mapping (SISM), National Bureau of Surveying and Mapping, China, 1997(in Chinese) ［7］USGS. National Mapping Program: Geospatial Data Standard, 1992 ［8］Zhu Q, Cheng C J. The fast generation and dynamic updating of TIN. Journal of Wuhan Technical University of Surveying and Mapping, 1998(in Chinese)     

The scheme for the database building and updating of 1∶10 000 digital elevation models

The National Bureau of Surveying and Mapping of China has planned to speed up the development of spatial data infrastructure (SDI) in the coming few years. This SDI consists of four types of digital products, i. e., digital orthophotos, digital elevation models, digital line graphs and digital raster graphs. For the DEM, a scheme for the database building and updating of 1∶10 000 digital elevation models has been proposed and some experimental tests have also been accomplished. This paper describes the theoretical (and/or technical) background and reports some of the experimental results to support the scheme. Various aspects of the scheme such as accuracy, data sources, data sampling spatial resolution, terrain modeling, data organization, etc are discussed.     

Cartographica incognita: ‘Dijital Jedis’, Satellite Salvation and the Mysteries of the ‘Missing Maps’

Like Participatory Geographic Information Systems (PGIS) and Public Participation Geographic Information Systems (PPGIS) crowdsourced collaborative mapping is often imagined as an alternative to conventional cartographic practice. This paper examines collaborative mapping projects designed to assist in humanitarian work and respond to catastrophes. These projects, their technological complexity and wide range of collaborators, including affected locals, international Non-Government Organisations (NGOs) and anonymous online contributors, invite closer consideration. In this article I unpick the gnarly question of how the remote sourcing of information through cloud collaboration and satellite imagery jostles with grounded work encouraging local control of local geoinformation. My critical analysis of these projects explores: (1) justifications for action – what is being promised through digital mapping as aid or satellite salvation?; (2) forms of participation – the role of ‘hotties’ ‘nodders’ and ‘digital jedis’; and (3) contingencies of mapping practices and the assemblages of actors within which they are embedded – as the mysteries of the ‘missing maps’. The conclusion considers differing approaches towards the inclusion of local knowledges within participatory digital aid mapping and identifies remote mapping practices that are both incognito and incognisant.     

The pyrogeography of sub-Saharan Africa: a study of the spatial non-stationarity of fire–environment relationships using GWR

This study analyses the relationship between fire incidence and some environmental factors, exploring the spatial non-stationarity of the phenomenon in sub-Saharan Africa. Geographically weighted regression (GWR) was used to study the above relationship. Environment covariates comprise land cover, anthropogenic and climatic variables. GWR was compared to ordinary least squares, and the hypothesis that GWR represents no improvement over the global model was tested. Local regression coefficients were mapped, interpreted and related with fire incidence. GWR revealed local patterns in parameter estimates and also reduced the spatial autocorrelation of model residuals. All the covariates were non-stationary and in terms of goodness of fit, the model replicates the data very well (R ² = 87%). Vegetation has the most significant relationship with fire incidence, with climate variables being more important than anthropogenic variables in explaining variability of the response. Some coefficient estimates exhibit locally different signs, which would have gone undetected by a global approach. This study provides an improved understanding of spatial fire–environment relationships and shows that GWR is a valuable complement to global spatial analysis methods. When studying fire regimes, effects of spatial non-stationarity need to be incorporated in vegetation-fire modules to have better estimates of burned areas and to improve continental estimates of biomass burning and atmospheric emissions derived from vegetation fires.     

The First Depiction of Two Superimposed Geographical Surfaces in One Autostereoscopic Map: Antarctica’s Topography and the Southern Ocean Seafloor

Within the past 10–15 years true-3D lenticular cartography has experienced a remarkable boost. In the course of this development, besides studies into its potential for thematic-cartographic representations, the synoptic depiction of physical surfaces (‘geo[graphical] surfaces’) has been playing a significant role. In this context the innovative holistic display of complex morphological and topographical conditions is of particular interest. The simultaneous representation of various cartographic parameters at different depths will deliver an enormous surplus of information transfer in the field of thematic cartography as well as in physical/topographic cartography. This paper describes the methodological development and generation of an autostereoscopic hardcopy display of Antarctic topography. The purpose was the simultaneous depiction of the two superimposed surfaces of both the ice-sheet and the rock-bed and, in addition, of the surrounding seafloor, thus displaying a vertical drop of more than 12,000?m.     

The Palestine Exploration Fund Map (1871–1877) of the Holy Land as a Tool for Analysing Landscape Changes: the Coastal Dunes of Israel as a Case Study

Abstract

The Palestine Exploration Fund (PEF) maps (1871–1877) are highly praised for their accuracy and completeness; however, no systematic analysis of their accuracy has been done to date. To study the potential of these 1:63,360 maps for a quantitative analysis of land cover changes over a period of time, I have compared them to 20th century topographic maps. The map registration error of the PEF maps was 74.4 m using 123 control points of trigonometrical stations and a 1st order polynomial. The median RMSE of all control and test points (n = 1104) was 153.6 m. As a case study of land cover changes, the area of coastal dunes as shown on the PEF maps was compared with that shown on British Mandate 1:20,000 topo-cadastral maps from c. 1930. In five of the six areas analysed, the yearly dunes movement rate was above the estimated annual error due to data resolution (2.96 m/year). The rate of dune movement south of Acre was found to be between 3.9 and 6.3 m/year (depending on the method used for map registration) between 1874 and 1930. Care should be taken when analysing historical maps, as it cannot be assumed that their accuracy is consistent at different parts or for different features depicted on them.     

Coloured Roads on Ordnance Survey First Edition 1 : 2500 Plans and One-Inch Maps 1897–1935, and the Rights Of Way Disclaimer

Abstract

In 1892 a government committee of inquiry into the Ordnance Survey suggested that the Survey should make a distinction between public and private second class roads at the one-inch scale. This study is confined to England and Wales and looks at the nineteenth-century practice of colouring roads on the large-scale plans, and compares the representation of coloured rural roads on early Ordnance Survey one-inch maps with near contemporary highway records of the county of Huntingdonshire, sixteen rural district councils in six counties and an estate in Suffolk. The results show that all but four of the coloured roads on the one-inch maps in these areas are recorded as publicly maintainable highways.     

The July 11, 1995 Myanmar–China earthquake: A representative event in the bookshelf faulting system of southeastern Asia observed from JERS-1 SAR images

On July 11, 1995, an Mw 6.8 earthquake struck eastern Myanmar near the Chinese border; hereafter referred to as the 1995 Myanmar–China earthquake. Coseismic surface displacements associated with this event are identified from JERS-1 (Japanese Earth Resources Satellite-1) SAR (Synthetic Aperture Radar) images. The largest relative displacement reached 60 cm in the line-of-sight direction. We speculate that a previously unrecognized dextral strike-slip subvertical fault striking NW–SE was responsible for this event. The coseismic slip distribution on the fault planes is inverted based on the InSAR-derived deformation. The results indicate that the fault slip was confined to two lobes. The maximum slip reached approximately 2.5 m at a depth of 5 km in the northwestern part of the focal region. The inverted geodetic moment was approximately Mw = 6.69, which is consistent with seismological results. The 1995 Myanmar–China earthquake is one of the largest recorded earthquakes that has occurred around the “bookshelf faulting” system between the Sagaing fault in Myanmar and the Red River fault in southwestern China.     

‘Lineaments’ the Potential Groundwater Zones in Hard Rock Area: A Case Study of Basaltic Terrain of WGKKC-2 Watershed from Kalmeswar Tehsil of Nagpur District,Central India

Hard rock aquifer system, as it lacks in primary porosity, is complex because of heterogeneity, and hence its performance solely depends on secondary factors such as weathering, fractures, joints and lineaments, etc. As a result, there is no uniformity in behavior of such aquifer system which varies with the intensity of factors causing secondary porosity. In view of this aquifer system of hard rock, particularly multilayered aquifer system such as basalt, the targeting of deeper aquifer system becomes uncertain. Under this situation, mapping of lineament assumes great importance particularly for targeting the deeper aquifer. In view of this, a small watershed WGKKC-2 falling in Nagpur District of Central India has been studied in detail to understand the significance of lineaments on governing deeper aquifer system. The study has been carried out by deploying remote sensing technique for delineation of hydro geomorphology and lineaments vis-à-vis performance of bore wells. The results are encouraging which mainly emphasize the role of lineament mapping in hard rock aquifer system for identification of groundwater potential zones.     

The static gravity field model DGM-1S from GRACE and GOCE data: computation, validation and an analysis of GOCE mission’s added value

We present a global static model of the Earth’s gravity field entitled DGM-1S based on GRACE and GOCE data. The collection of used data sets includes nearly 7 years of GRACE KBR data and 10 months of GOCE gravity gradient data. The KBR data are transformed with a 3-point differentiation into quantities that are approximately inter-satellite accelerations. Gravity gradients are processed in the instrumental frame. Noise is handled with a frequency-dependent data weighting. DGM-1S is complete to spherical harmonic degree 250 with a Kaula regularization being applied above degree 179. Its performance is compared with a number of other satellite-only GRACE/GOCE models by confronting them with (i) an independent model of the oceanic mean dynamic topography, and (ii) independent KBR and gravity gradient data. The tests reveal a competitive quality for DGM-1S. Importantly, we study added value of GOCE data by comparing the performance of satellite-only GRACE/GOCE models with models produced without GOCE data: either ITG-Grace2010s or EGM2008 depending on which of the two performs better in a given region. The test executed based on independent gravity gradients quantifies this added value as 25–38 % in the continental areas poorly covered with terrestrial gravimetry data (Equatorial Africa, Himalayas, and South America), 7–17 % in those with a good coverage with these data (Australia, North America, and North Eurasia), and 14 % in the oceans. This added value is shown to be almost entirely related to coefficients below degree 200. It is shown that this gain must be entirely attributed to gravity gradients acquired by the mission. The test executed based on an independent model of the mean dynamic topography suggests that problems still seem to exist in satellite-only GRACE/GOCE models over the Pacific ocean, where noticeable deviations between these models and EGM2008 are detected, too.     

Horizontal and vertical accuracy of Google Earth®: comment on ‘Positional accuracy of the Google Earth terrain model derived from stratigraphic unconformities in the Big Bend region,Texas, USA’ by S.C. Benker,R.P. Langford and T.L. Pavlis

Comment on ‘Positional accuracy of the Google Earth terrain model derived from stratigraphic unconformities in the Big Bend region, Texas, USA’ by S.C. Benker, R.P. Langford and T.L. Pavlis (Geocarto Int. 26:291–303, doi: 10.1080/10106049.2011.568125).