共查询到20条相似文献，搜索用时 31 毫秒
1.
3D desktop-based virtual environments provide a means for displaying quantitative data in context. Data that are inherently spatial in three dimensions may benefit from visual exploration and analysis in relation to the environment in which they were collected and to which they relate. We empirically evaluate how effectively and efficiently such data can be visually analyzed in relation to location and landform in 3D versus 2D visualizations. In two experiments, participants performed visual analysis tasks in 2D and 3D visualizations and reported insights and their confidence in them. The results showed only small differences between the 2D and 3D visualizations in the performance measures that we evaluated: task completion time, confidence, complexity, and insight plausibility. However, we found differences for different datasets and settings suggesting that 3D visualizations or 2D representations, respectively, may be more or less useful for particular datasets and contexts. 相似文献
2.
Current activities and recent progress on constructive approximation and numerical analysis in physical geodesy are reported
upon. Two major topics of interest are focused upon, namely trial systems for purposes of global and local approximation and
methods for adequate geodetic application. A fundamental tool is an uncertainty principle, which gives appropriate bounds
for the quantification of space and momentum localization of trial functions. The essential outcome is a better understanding
of constructive approximation in terms of radial basis functions such as splines and wavelets.
Received: 4 May 1999 / Accepted: 21 May 1999 相似文献
3.
Paulo Raposo 《The Cartographic journal》2013,50(3):299-300
AbstractThe internet provides almost unlimited opportunities for accessing information and on-line services. The government of Canada is restructuring its services to take advantage of this medium. While web-based distribution of visual maps has been a reality for several years, production of maps for people with special needs poses new challenges, as additional accessibility requirements have to be met. This paper shares the Canadian experience of developing accessible tactile and audio-tactile maps for blind and partially sighted people. 'Government On-Line' involves partnerships between government departments to develop a portal specifically tailored to providing information and services for people with disabilities, their families, care givers and service providers. The Mapping for Visually Impaired Web site is an integral part of this broader initiative providing tactile maps for education, mobility training, transportation and tourism. Additionally a Web-4-All project will facilitate learning about Canada's geography and improve mobility options for blind and partially sighted people. 相似文献
4.
Bijeesh Kozhikkodan Veettil Ulisses Franz Bremer Sergio Florêncio de Souza Éder Leandro Bayer Maier Jefferson Cardia Simões 《国际地球制图》2016,31(5):544-556
This research focuses on the recent variations in the annual snowline and the total glaciated area of the Nevado Coropuna in the Cordillera Ampato, Peru. Maximum snowline altitude towards the end of dry season is taken as a representative of the equilibrium line altitude of the year, which is an indirect measurement of the annual mass balance. We used Landsat and IRS LISS3 images during the last 30 years due to its better temporal coverage of the study site. It is found that there was a decrease of 26.92% of the glaciated area during 1986–2014. We calculated the anomalies in precipitation and temperature in this region and also tried to correlate the changes in glacier parameters with the combined influence of El Niño – Southern Oscillation (ENSO) and pacific decadal oscillation (PDO). It is concluded that the snowline of Nevado Coropuna has been fluctuated during ENSO, and maximum fluctuations were observed when ENSO and PDO were in phase. 相似文献
5.
The paper suggests a modeling approach for assessing economic and social impacts of changes in urban forms and commuting patterns that extends a multi-regional input–output framework by incorporating a set of commuting-related consequences. The Lisbon Metropolitan Area case with an urban re-centralization scenario is used as an example to illustrate the relevance of this modeling approach for analyzing commuting-related changes in regional income distribution on the one side and in household consumption structures on the other. 相似文献
6.
Self‐localization is the process of identifying one's current position on a map, and it is a crucial part of any wayfinding process. During self‐localization the wayfinder matches visually perceptible features of the environment, such as landmarks, with map symbols to constrain potential locations on the map. The success of this visual matching process constitutes an important factor for the success of self‐localization. In this research we aim at observing the visual matching process between environment and map during self‐localization with real‐world mobile eye tracking. We report on one orientation and one self‐localization experiment, both in an outdoor urban environment. The gaze data collected during the experiments show that successful participants put significantly more visual attention to those symbols on the map that were helpful in the given situation than unsuccessful participants. A sequence analysis revealed that they also had significantly more switches of visual attention between map symbols and their corresponding landmarks in the environment, which suggests they were following a more effective self‐localization strategy. 相似文献
7.
Since there is an increasing demand for integrating landscape ecology and urban planning theories to study complex urban ecosystems and establish rational and ecological urban planning, we introduced a new concept-urban functional landscapes which can be reclassified based on detailed land use data to fulfill the various urban functions, such as residential, commercial, industrial, and infrastructure purposes. In this paper, urban functional landscapes were defined based on urban land use data produced from Pleiades images, and then landscape metrics and population density were combined to identify the urban functional zones along an urban–rural gradient. The features of urban functional landscape patterns and population density were also analyzed, and their relationship has been explored. The results showed that the pattern of urban functional landscapes and population density in the urban functional zones (Urban center, Urban peripheral area, Landscape barrier, Satellite city and Far-suburb) along the urban–rural gradient in Xiamen doesn't totally conform to the classical theories in spatial and social aspects. Urban functional landscapes is potential of acting as bridges between the landscape ecology and urban planning theories, providing scientific support for rational urban landscape planning and urban land use policy making. 相似文献
8.
《ISPRS Journal of Photogrammetry and Remote Sensing》1999,54(2-3):68-82
This tutorial paper gives an introduction and overview of various topics related to airborne laser scanning (ALS) as used to measure range to and reflectance of objects on the earth surface. After a short introduction, the basic principles of laser, the two main classes, i.e., pulse and continuous-wave lasers, and relations with respect to time-of-flight, range, resolution, and precision are presented. The main laser components and the role of the laser wavelength, including eye safety considerations, are explained. Different scanning mechanisms and the integration of laser with GPS and INS for position and orientation determination are presented. The data processing chain for producing digital terrain and surface models is outlined. Finally, a short overview of applications is given. 相似文献
9.
The problem of integer estimation has drawn a lot of attention in the past decade, and is now often considered solved. However, a parameter resolution theory cannot be considered complete without rigorous measures for validating the parameter solution. 相似文献
10.
It is necessary to estimate heavy metal concentrations within soils for understanding heavy metal contaminations and for keeping the sustainable developments of ecosystems.This study,with the floodplain along Le’an River and its two branches in Jiangxi Province of China as a case study,aimed to explore the feasibility of estimating concentrations of heavy metal lead(Pb),copper(Cu) and zinc(Zn) within soils using laboratory-based hyperspectral data.Thirty soil samples were collected,and their hyperspectral data,soil organic matters and Pb,Cu and Zn concentrations were measured in the laboratory.The potential relations among hyperspectral data,soil organic matter and Pb,Cu and Zn concentrations were explored and further used to estimate Pb,Cu and Zn concentrations from hyperspectral data with soil organic matter as a bridge.The results showed that the ratio of the first-order derivatives of spectral absorbance at wavelengths 624 and 564 nm could explain 52% of the variation of soil organic matter;the soil organic matter could ex-plain 59%,51% and 50% of the variation of Pb,Cu and Zn concentrations with estimated standard errors of 1.41,48.27 and 45.15 mg·kg-1;and the absolute estimation errors were 8%-56%,12%-118% and 2%-22%,and 50%,67% and 100% of them were less than 25% for Pb,Cu and Zn concentration estimations.We concluded that the laboratory-based hyperspectral data hold potentials in esti-mating concentrations of heavy metal Pb,Cu and Zn in soils.More sampling points or other potential linear and non-linear regression methods should be used for improving the stabilities and accuracies of the estimation models. 相似文献
11.
It is necessary to estimate heavy metal concentrations within soils for understanding heavy metal contaminations and for keeping the sustainable developments of ecosystems. This study, with the floodplain along Le’an River and its two branches in Jiangxi Province of China as a case study, aimed to explore the feasibility of estimating concentrations of heavy metal lead (Pb), copper (Cu) and zinc (Zn) within soils using laboratory-based hyperspectral data. Thirty soil samples were collected, and their hyperspectral data, soil organic matters and Pb, Cu and Zn concentrations were measured in the laboratory. The potential relations among hyperspectral data, soil organic matter and Pb, Cu and Zn concentrations were explored and further used to estimate Pb, Cu and Zn concentrations from hyperspectral data with soil organic matter as a bridge. The results showed that the ratio of the first-order derivatives of spectral absorbance at wavelengths 624 and 564 nm could explain 52% of the variation of soil organic matter; the soil organic matter could explain 59%, 51% and 50% of the variation of Pb, Cu and Zn concentrations with estimated standard errors of 1.41, 48.27 and 45.15 mg·kg?; and the absolute estimation errors were 8%–56%, 12%–118% and 2%–22%, and 50%, 67% and 100% of them were less than 25% for Pb, Cu and Zn concentration estimations. We concluded that the laboratory-based hyperspectral data hold potentials in estimating concentrations of heavy metal Pb, Cu and Zn in soils. More sampling points or other potential linear and non-linear regression methods should be used for improving the stabilities and accuracies of the estimation models. 相似文献
12.
Recent developments in data visualization, developer Application Program Interfaces (APIs), and web services reinforce a long American tradition of statistical mapping and innovation at the US Census Bureau. Consistent with other international statistical agencies, the Census Bureau has used contemporary innovations in statistical mapping and data visualization to disseminate national census results for over 14 decades. The US Census Bureau’s data products and analyses have enabled decision makers and the public to access census results quickly and easily. The new information technology environment requires the Census Bureau to more rapidly expedite these results and deliver mapping products to new customers as well as to its traditional data consumers. The Census API has empowered developers and commercial companies to test the limits of a new emerging world of big data solutions. This article presents some of the most recent data visualization products from the Census Bureau, including an expanding Data Visualization Gallery to merge geospatial information and statistics on the map. 相似文献
13.
Over the last years, geospatial web platforms, social media, and volunteered geographic information (VGI) have opened a window of opportunity for traditional Public Participatory GIS (PPGIS) to usher in a new era. Taking advantage of these technological achievements, this paper presents a new approach for a citizen-orientated framework of spatial planning that aims at integrating participatory community work into existing decision-making structures. One major cornerstone of the presented approach is the application of a social geoweb platform (the GeoCitizen platform) that combines geo-web technologies and social media in one single tool allowing citizens to collaboratively report observations, discuss ideas, solve, and monitor problems in their living environment at a local level. This paper gives an account of an ongoing participatory land-zoning process in the Capital District of Quito, Ecuador, where the GeoCitizen platform is applied in a long-term study. 相似文献
14.
《制图学和地理信息科学》2013,40(4):257-268
Much progress has been made in the field of web-based cartography through standards developed by the Open Geospatial Consortium (OGC). While automated access and presentation of cartographic data have been defined, the services for automated generalization are yet to be standardized. This paper aims to show advantages of applying the service concept to generalization and suggests several classification schemas of generalization services at different levels of granularity. A detailed explanation of a real implemented Generalization Service is provided. We show how software developers can make their generalization functionality available as a service and how these services can be accessed dynamically. For the implementation, the open source Java Unified Mapping Platform (JUMP) was extended to work as a framework for generalization. Generalization services could be used in different application scenarios, for instance as a middleware component extending a web map service with adaptive zooming or as stand-alone services supporting the production of topographic maps by national mapping agencies. They may also allow the development of a common research platform, where researchers would have access to a common generalization framework. 相似文献
15.
The reduction of untouched areas and the increase in residential, agricultural and industrial areas have gained speed in recent decades. As a result of the changes, one can often observe the disappearance of landmarks that had been connected to production, habitation and transportation. The first step for the preservation of landmarks is their identification and inventorization. In the ordinary sense of the word, ‘landmarks’ mean the important landscape heritage of national history and culture, which need to be identified, protected and preserved for future generations. The purpose of the TÉKA project was to compile a landmark cadastral register that will contribute to the preservation of landscape-related and cultural heritage in Hungary. The landmark cadastral is a Wikipedia-like GIS-based web site. One of the novelties of the TÉKA database is that the data obtained from various sources are gathered in a common, online GIS and integrated into a uniform meta database. 相似文献
16.
SHEN Wenbin NING Jinsheng 《地球空间信息科学学报》2007,10(1):4-11
The problem of separating gravitation from inertia is discussed in very general sense, and the conclusion is positive: man can separate gravitation from inertia, if various observation techniques are applied for. The accelerometer's position problem in satellite gravimetry is investigated, and the additional acceleration effect due to the position error of an instrument as well as the difference between the mass center and the gravity center is explored. 相似文献
17.
Steffi Burmeister Konrad Willner Valentina Schmidt Jürgen Oberst 《Journal of Geodesy》2018,92(9):963-973
A functional model for a bundle block adjustment in the inertial reference frame was developed, implemented and tested. This approach enables the determination of rotation parameters of planetary bodies on the basis of photogrammetric observations. Tests with a self-consistent synthetic data set showed that the implementation converges reliably toward the expected values of the introduced unknown parameters of the adjustment, e.g., spin pole orientation, and that it can cope with typical observational errors in the data. We applied the model to a data set of Phobos using images from the Mars Express and the Viking mission. With Phobos being in a locked rotation, we computed a forced libration amplitude of \(1.14^\circ \pm 0.03^\circ \) together with a control point network of 685 points. 相似文献
18.
ABSTRACTGeographic information technologies (GIT) have matured, have become pervasive throughout many types of organizations over recent decades and gained a wide range of attention in diverse sectors of society. The goal of this paper is to identify the main drivers and uses of GIT in organizations and to give an overview of GIT uses in developing countries with a focus on a case study developed for Mozambique by analyzing the results of a survey of 123 Mozambican organizations that are current GIT users. The results show that the main drivers behind are compatibility, complexity, competitive pressure, donor pressure, government policy, intention to adopt, innovation, relative advantage, security, and technology competence. Organizations of the public and private sectors use GIT for customer/resource/risk management, decision support, education, research, monitoring, prediction, simulation, suitability analysis, sustainability, use and access. 相似文献
19.
Multiresolution Terrian Model in GIS 总被引：1，自引：0，他引：1
DEM, which becomes a major component of geographic information processing in earth and engineering sciences, has been studied in the GIS literature for a long time. We use DEM to represent the terrain in GIS. The more data are available, the better representations of a terrain can be built. But not all tasks in the framework of a given application necessarily require the same accuracy, and even a single task may need different levels of accuracy in different areas of the domain. Multiresolution models, such as LOD, offer the possibility of representing and analyzing a terrain at a range of different levels of detail. In this paper, some key issues in multiresolution DEM model are studied. Three main models are focused on Hierarchical TIN(HTIN), multiresolution terrain model based Delaunay and Hierarchical Dynamic Simplification. The advantages and disadvantages of these methods are analyzed. The technology of tile to tile edge match is studied to maintain the consistency between adjacent edges and tile edges in HTIN model. And the Hypergraph based Objected oriented Model(HOOM) is presented to divide and code spatial area and describe the terrain feature in adding and deleting points based on Delaunay rule retriangulating. The conclusions have been drawn in the end. 相似文献
20.