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1.
Maps, created through the collection, assembly, and analysis of spatial data are used to support government planning and decision-making. Traditionally, spatial data used to create maps are collected, controlled, and disseminated by government, although over time, this role has shifted. This shift has been driven by the availability of alternate sources of data collected by private sector companies, and data contributed by volunteers to open mapping platforms, such as OpenStreetMap. In theorizing this shift, we provide examples of how governments use data sovereignty as a tool to shape spatial data collection, use, and sharing. We frame four models of how governments may navigate shifting spatial data sovereignty regimes; first, with government retaining complete control over data collection; second, with government contracting a third party to provide specific data collection services, but with data ownership and dissemination responsibilities resting with government; third, with government purchasing data under terms of access set by third party data collectors, who disseminate data to several parties, and finally, with government retreating from or relinquishing data sovereignty altogether. Within this rapidly changing landscape of data providers, we propose that governments must consider how to address data sovereignty concerns to retain their ability to control data use in the public interest. 相似文献
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3.
《The Cartographic journal》2013,50(4):329-341
AbstractThe background and context to the cartography of the French military engineer Lewis Petit and his work in Scotland is explained. Petit was responsible for drafting the earliest plans and profiles of four castles in the north-west Highlands of Scotland (1714), as well as the earliest town plans of Perth and Inverness (1716). A consideration of their functions, particularly through the Board of Ordnance archives, allows a better understanding of these plans and their value as historical sources, as well as their accurate dating. Petit's work reflected national and international developments, including war in Europe and the Jacobite rebellions in Britain. His cartography illustrates the spread of new European military theories and practices, at a time when a professional corps of military engineers was being established in Great Britain. Through studying Petit and his maps we can gain a fuller understanding not only of the Board of Ordnance in Hanoverian Scotland, but also of the militarisation of cartography in the eighteenth century, and the emergence of standards relating to colour, scale and terminology. 相似文献
4.
Deterministic, stochastic, hybrid and band-limited modifications of Hotine’s integral 总被引：2，自引：1，他引：1
W. E. Featherstone 《Journal of Geodesy》2013,87(5):487-500
Global Navigation Satellite System positioning of gravity surveys permits geoid computation via Hotine’s integral. A suite of modifications is presented so that the user can tune the relative contributions of truncation and data errors in a combined solution for a regional geoid model from gravity disturbances. 相似文献
5.
none 《The Cartographic journal》2013,50(2):155-175
AbstractThe organization lineage of the UK Defence Geographic and Imagery Intelligence Agency can be traced back to the seventeenth century. For much of this time the organization, bearing a succession of different titles, formed only a very small section of the armed forces, and, until the World War of 1914–1918, its main duties were the creation and maintenance of a map collection and the acquisition of geographical data of foreign countries. The survey and mapping innovations made during the war greatly enlarged the remit of what was now termed the Geographical Section General Staff (MI4). This paper outlines the work of MI4 in the inter-war years taking account of the principal personalities involved, and traces the controversial background to the creation in 1943 of the Directorate of Military Survey — the immediate predecessor of the DGIA. 相似文献
6.
Since the release of the ETOPO1 global Earth topography model through the US NOAA in 2009, new or significantly improved topographic data sets have become available over Antarctica, Greenland and parts of the oceans. Here, we present a suite of new 1′ (arc-min) models of Earth’s topography, bedrock and ice-sheets constructed as a composite from up-to-date topography models: Earth2014. Our model suite relies on SRTM30_PLUS v9 bathymetry for the base layer, merged with SRTM v4.1 topography over the continents, Bedmap2 over Antarctica and the new Greenland bedrock topography (GBT v3). As such, Earth2014 provides substantially improved information of bedrock and topography over Earth’s major ice sheets, and more recent bathymetric depth data over the oceans, all merged into readily usable global grids. To satisfy multiple applications of global elevation data, Earth2014 provides different representations of Earth’s relief. These are grids of (1) the physical surface, (2) bedrock (Earth’s relief without water and ice masses), (3) bedrock and ice (Earth without water masses), (4) ice sheet thicknesses, (5) rock-equivalent topography (ice and water masses condensed to layers of rock) as mass representation. These models have been transformed into ultra-high degree spherical harmonics, yielding degree 10,800 series expansions of the Earth2014 grids as input for spectral modelling techniques. As further variants, planetary shape models were constructed, providing distances between relief points and the geocenter. The paper describes the input data sets, the development procedures applied, the resulting gridded and spectral representations of Earth2014, external validation results and possible applications. The Earth2014 model suite is freely available via http://ddfe.curtin.edu.au/models/Earth2014/. 相似文献
7.
Airborne gamma ray spectrometric (AGRS) and magnetic (AM) surveys were undertaken between 1986-1987 by Atomic Minerals Division, to locate uranium mineralisation along Son-Narmada rift zone. The imaging and interpretation of gridded AGRS data revealed many areas of anomalous radio elemental concentrations. These areas have been defined by taking thresholds as U ≥ 6 ppm, Th ≥ 24 ppm, K ≥ 2.3% and Total counts ≥ 5000 cps. The AGRS data integration with the satellite data viz., Landsat Multi spectral Scanner (MSS), Thematic Mapper (TM), and IRS LISS II data on different scales indicated the lithostructural controls of uranium mineralisation and also the predominance of the potash metasomatism in the vicinity of the southern Son rift and soda metasomatism further away in the south. p ]Systematic follow up ground checking of the target area located in the North Sagobandh area resulted in delineating the areas of K metasomatism, anatexis and grissenisation as the areas showing ≥ 2.3%K values. The depleted K, Th, and high U/Th values show zones of albitisation and oligoelasisation. The trends of radiometric breaks depicted by total counts distribution patterns defined the tectonostratigraphic boundaries. Besides these 26 radioactive anomalies with grades ranging from eU3O/0./012–0.18%, U3Ox B/r <0.01–0.3% and ThO2 0.00.5–0.1% having strike length 50–500 meters and outcrop thickness .5–2.5 meters. Ten locations of inland riverine sand placers of heavy minerals containing REE bearing minerals i.e. xenotime, monazite, rutile, ilmenite, zircon and traces of columbite-tantalite have been identified by using thorium and mixed source (U+Th) anomaly map. These sand placers have channel lengths of 100 - >500 meters and width of 1–2.5 meters, containing l.5%–9.04% heavy minerals. 相似文献
8.
Niladri Gupta Md. Aktaruzzaman Chen Wang 《Journal of the Indian Society of Remote Sensing》2012,40(3):457-466
Eutrophication in lakes, estuaries and rivers occur due to over-enrichment with nutrients. Amongst the various nutrients Nitrogen (N) and Phosphorous (P) are the elements which are considered as the major pollutants. The present study looks into the problem of managing nutrient losses both from point sources and diffuse sources. The study was carried out in the River R?nne? catchment in South of Sweden where N and P have been assessed by creation of a pollution inventory based on GIS technology. The nutrient loads from different land use types were estimated using export coefficients and evaluated using monitoring data. A comparative analysis is done on the measured and estimated N and P leaching from diffused sources and point sources. Protective zones were suggested to decrease the P export from agricultural land, and the distribution of construction cost was analyzed among administrative regions according to the proportion of catchments, cultivated land, nutrient leaching, protective zone and length of river section within each municipality. The estimated error of the nutrient amount from landuse using GIS is 9.75% and 12.71% for N and P, respectively. The diffused sources contribute 91.53% and 94.74% of the total N and total P respectively, so the creation of a protective zone could be an effective way to decrease the nutrient export. The study demonstrates the power of GIS as a tool to analyze problems related to environmental monitoring and planning at administrative level, which could help in decision making and support for better management of the water resources. 相似文献
9.
Driven by various natural and anthropogenic factors, Poyang Lake, the largest freshwater lake in China, has experienced significant land use/cover changes in the past few decades. The aim of this study is to investigate the spatial–temporal patterns of abrupt changes and detect their potential drivers in Poyang Lake, using time-series Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day maximum value composite vegetation indices between 2000 and 2012. The breaks for additive seasonal and trend (BFAST) method was applied to the smoothed time-series normalized difference vegetation index (NDVI), to detect the timing and magnitude of abrupt changes in the trend component. Large part of Poyang Lake (98.9% for trend component) has experienced abrupt changes in the past 13 years, and the change patterns, including the distributions in timing and magnitudes of major abrupt trend changes between water bodies and land areas were clearly differentiated. Most water bodies had abrupt increasing NDVI changes between 2010 and 2011, caused by the sequential severe flooding and drought in the two years. In contrast, large parts of the surrounding land areas had abrupt decreasing NDVI changes. Large decreasing changes occurred around 2003 at the city of Nanchang, which were driven by urbanization. These results revealed spatial–temporal land cover changing patterns and potential drivers in the wetland ecosystem of Poyang Lake. 相似文献
10.
Abstract Image mapping using data from visible and infrared sensors has, as a major drawback, the frequent cloud cover experienced in many countries. This is one of the main reasons why topographic maps at 1:100,000 scale and larger are often outdated. The results of a study which investigated the possibilities of fusing up‐to‐date spaceborne microwave data with existing images from optical sensors for topographic map updating at a scale of 1:100, 000 are presented in this paper. A key issue researched was the influence of geometric distortions and corrections of remote sensing data on the results of pixel based digital image fusion. After having terrain‐geocoded and radiometrically enhanced imagery from the Landsat, SPOT, ERS‐1 and JERS‐1 satellites, the data were fused applying a variety of colour transformation techniques as well as statistical or arithmetic methods. Initially, the image fusion was implemented using images covering a test site in the north of The Netherlands in order to calibrate specified combinations and techniques in a rather flat area. With the experience gained, the remote sensing data acquired over the research site were processed. The research test site is located in a typical Developing Country in the humid Tropics, on the mountainous south‐west coast of Sumatra in Indonesia. The results of the various applied techniques and image combinations were evaluated with reference to their capability to overcome the cloud cover problem. New combinations of techniques and images were developed as result of an optimisation process. The research produced two prototypes of annotated 1:100,000 scale image maps containing fused, cloud‐free optical/microwave imagery. 相似文献
11.
The availability of Very High Resolution (VHR) optical sensors and a growing image archive that is frequently updated, allows the use of change detection in post-disaster recovery and monitoring for robust and rapid results. The proposed semi-automated GIS object-based method uses readily available pre-disaster GIS data and adds existing knowledge into the processing to enhance change detection. It also allows targeting specific types of changes pertaining to similar man-made objects such as buildings and critical facilities. The change detection method is based on pre/post normalized index, gradient of intensity, texture and edge similarity filters within the object and a set of training data. More emphasis is put on the building edges to capture the structural damage in quantifying change after disaster. Once the change is quantified, based on training data, the method can be used automatically to detect change in order to observe recovery over time in potentially large areas. Analysis over time can also contribute to obtaining a full picture of the recovery and development after disaster, thereby giving managers a better understanding of productive management and recovery practices. The recovery and monitoring can be analyzed using the index in zones extending from to epicentre of disaster or administrative boundaries over time. 相似文献
12.
LIU Shaochuang LU Pingli LIU Donghui JIN Peidong 《地球空间信息科学学报》2007,10(1):51-56
For centuries, explorers and scientists from different countries had made their own conclusions on the source of the Mekong. However, the geographic source of the Mekong is still arguable because of the complexity of the Mekong source water system, inaccessible environment and the varied technologies used by those explorers and scientists. The satellite remote sensing technology has been used to pinpoint the source of the Mekong, associated with the on-the-spot investigations made by the authors in June 1999 and September 2002. The actual length of the Mekong has also been calculated. 相似文献
13.
Investigation of rainfall–run-off modelling is an important subject to develop any available means to water supply, which maintains human life such as run-off harvesting method. This study aims to analyse and understand the rainfall–run-off relationship in a part of Babil city, Iraq. Curve number which is a function of land use, soil texture, soil moisture and land slope is used in this study. Remote sensing and GIS are used to analyse the data and to produce the run-off depth map for the study area. Then, the run-off depth is used with rainfall to investigate the relationship between them using linear correlation. This study showed a strong linear relationship between rainfall and run-off (R2 = 0.992). It indicates that in the absence of rainfall data, run-off data can be used to estimate rainfall amount. Also, the study revealed through water balance analysis that there is an average monthly change in storage. 相似文献
14.
none 《The Cartographic journal》2013,50(2):119-134
AbstractFighting the 1914–18 war largely on enemy territory in both the east and the west, German was at a disadvantage compared to the Allies when it came to survey and mapping as it did have access to much of the geodetic, topographic and cartographic data, relating to this terrain, necessary for modern warfare — in particular for artillery survey. German and Austria did, however, have a commanding lead in terrestrial and aerial photogrammetry, and the latter was to prove crucial in the production of accurate large-scale maps of enemy and occupied territory. Despite strong forces of conservatism in the high and field commands and in the artillery and military survey organizations, new air survey methods based on the photogoniometer and radial triangulation were rapidly developed. Through continual laboratory and field experimentation and testing, German was to increase her lead in aerial photogrammetry, and by the end of the war had not only set up a completely new air survey organization but was developing a new generation of optical-mechanical stereoplotting instruments of great precision. German progress was not, however, evident in all fields of military survey, and this paper examines the approaches taken by German to survey and mapping on the Western Front, and briefly compares and contrasts them with those of the Allies. 相似文献
15.
LIANG Yong LU Xiushan ZHANG Degui LIANG Fu 《地球空间信息科学学报》2002,5(1):68-73
This paper deals with the content,purpose and significance of digital agriculture,and gives a brief introduction to digital earth,digital China and digital agriculture abroad.The main content of digital agriculture includes the construction of database,Metadata standard,monitoring system,forecasting and decision-making system,information-releasing system.The main technical supports of digital agriculture are 3S technology,Metadata management technology,fast-handling technology of remote sensing,the technology of computer wide-band network and virtual reality,intelligent agriculture machinery and field real-time information collecting technology.The advantages of implementing digital agriculture in China and the problems worthy of attention are pointed out as well. 相似文献
16.
Groundwater assessment has been carried out through hydrogeomorphological and geophysical survey. Remotely sensed data has been used to delineate the hydrogeomorphological units. Each hydrogeomorphological unit has been further sub-divided based on the tone, texture and pattern. These units its have been categorised based on depth of weathering, local geomorphological association, recharge characteristics etc. The top layer resistivity of hydrogeomorphological units has been analysed by electrical resistivity method. Correlation between different sub-units of same hydrogeomorphic unit and top soil resistivity has been attempted. The correlation and integration of resistivity map with geomorphological map were carried out through. ‘GRAM’ Geographic information System, This has helped in better understanding the surface resistivity pattern. These sub divisions have different geohydrological and recharge characteristics. Resistivity zonation map prepared on the basis of limited field data anfd through interpolation/extrapolation can be modified/corrected with the help of information derived from remotely sensed data to obtain more realistic picture. 相似文献
17.
Evaluation of Goddard’s LiDAR,hyperspectral, and thermal data products for mapping urban land-cover types 总被引：1，自引：0，他引：1
Goddard’s LiDAR (Light Detection And Ranging), hyperspectral and thermal (G-LiHT) airborne imager is a new system to advance concepts of data fusion for worldwide applications. A recent G-LiHT mission conducted in June 2016 over an urban area opens a new opportunity to assess the G-LiHT products for urban land-cover mapping. In this study, the G-LiHT hyperspectral and LiDAR-canopy height model (LiDAR-CHM) products were evaluated to map five broad land-cover types. A feature/decision-level fusion strategy was developed to integrate two products. Contemporary data processing techniques were applied, including object-based image analysis, machine-learning algorithms, and ensemble analysis. Evaluation focused on the capability of G-LiHT hyperspectral products compared with multispectral data with similar spatial resolution, the contribution of LiDAR-CHM, and the potential of ensemble analysis in land-cover mapping. The results showed that there was no significant difference between the application of the G-LiHT hyperspectral product and simulated Quickbird data in the classification. A synthesis of G-LiHT hyperspectral and LiDAR-CHM products achieved the best result with an overall accuracy of 96.3% and a Kappa value of 0.95 when ensemble analysis was applied. Ensemble analysis of the three classifiers not only increased the classification accuracy but also generated an uncertainty map to show regions with a robust classification as well as areas where classification errors were most likely to occur. Ensemble analysis is a promising tool for land-cover classification. 相似文献
18.
David Underwood 《GPS Solutions》1999,3(2):48-52
The use of the Global Positioning System (GPS) for position and attitude determination has been exploited for many years.
In these systems, it was required that multiple antennas maintained phase lock to common view satellites for long periods
of time in order to determine integer ambiguities. The challenge to overcome with the ballistic space probe is the high rotational
spin of this particular rocket. The antennas, mounted on the outside skin of the rocket, are in full view of each satellite
only for a fraction of a second before the rocket core eclipses them as it rotates. The antennas rarely see common satellites.
This article describes as system that overcomes these obstacles and provides position, acceleration, attitude, and rotation
rate. The approach uses a two-antenna system. One antenna is mounted either side of the rocket facing out. A hybrid tracking
channel combines signals from both antennas to overcome the signal blockage due to the rocket core as well as to defeat the
effect on the tracking channel due to the spin. The amplitude and phase of the spin rotation signature from each satellite
is extracted from the dual antenna data and used to compute the attitude and spin rate of the vehicle. ? 1999 John Wiley &
Sons, Inc. 相似文献
19.
Multi-technique space geodetic analysis software has been developed which allows to combine data on the observation level. In addition to local tie information, site-wise common parameters, i.e., troposphere and clocks, can be estimated with this software. Thus, it will be discussed how common parameters have to be estimated and where biases/offsets need to be taken into account. To test such a novel concept, Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI) data from the CONT11 campaign are being utilized. Since the VLBI baselines of this campaign extend over several thousands of kilometers, GPS data are processed in precise-point positioning mode and satellite orbits and clocks are kept fixed to the IGS final products. From the obtained results, it can be shown that the combination of space geodetic data on the observation level leads to a consistent improvement of station position repeatability as well as nuisance parameters like troposphere estimates. Furthermore, estimation of common parameters (troposphere or clocks) at co-located sites helps to improve the solution further and derive an utmost physically consistent model of the concerned parameters. 相似文献
20.