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1.
《制图学和地理信息科学》2013,40(3):167-182
One of the most fundamental steps in map creation is the transformation of information from the surface of a globe onto a flat map. Mapmakers have developed and used hundreds of different map projections over the past 2,000 years, yet there is no perfect choice because every map projection uniquely alters some aspect of space during the transformation process. Detailed information about the type, amount, and distribution of distortion is essential for choosing the best projection for a particular map or data set. The distortion inherent in projections can be measured and symbolized much like any other map variable. Methods for symbolizing map projection distortion are reviewed, with each method described and illustrated in graphical form. The symbolization methods are collected under ten separate headings organized from simple to more complex in terms of interpretation. Most of these methods are highly effective at communicating distortion, yet they are rarely used beyond textbooks and technical documentation. Map projections and the distortions they carry need to be better understood by spatial data developers, distributors, and users. Map distortion should be carried along with map data as confidence layers, and the easily accessible distortion displays should be available to help in the selection of map projections. There is a suitably wide array of symbolization methods to match any need from basic education to research. 相似文献
2.
《制图学和地理信息科学》2013,40(4):243-255
Designing usable geovisualization tools is an emerging problem in GIScience software development. We are often satisfied that a new method provides an innovative window on our data, but functionality alone is insufficient assurance that a tool is applicable to a problem in situ. As extensions of the static methods they evolved from, geovisualization tools are bound to enable new knowledge creation. We have yet to learn how to adapt techniques from interaction designers and usability experts toward our tools in order to maximize this ability. This is especially challenging because there is limited existing guidance for the design of usable geovisualization tools. Their design requires knowledge about the context of work within which they will be used, and should involve user input at all stages, as is the practice in any human-centered design effort. Toward that goal, we have employed a wide range of techniques in the design of ESTAT, an exploratory geovisualization toolkit for epidemiology. These techniques include; verbal protocol analysis, card-sorting, focus groups, and an in-depth case study. This paper reports the design process and evaluation results from our experience with the ESTAT toolkit. 相似文献
3.
《制图学和地理信息科学》2013,40(3):157-169
In this study, the pseudo-cylindrical projection of Franz Mayr is examined in detail. The computation of one of Mayr's projection equations depends on the solution of an elliptical integral. It is this characteristic of the projection that most likely contributes to it being the neglected one among the group of the pseudo-cylindrical projections available today. Franz Mayr used the Legendre tables for the elliptical functions E and F and gave the plane coordinates within one-degree latitude intervals on the 90° meridian. The research reported here derives analytical expressions instead of using the elliptical integral and the interpolation between the table values. Four different solutions have been introduced for mapping applications. The distortion quantities are also presented and discussed. 相似文献
4.
Tissot's Indicatrix and regular grids have been used for assessing map projection accuracies. Despite their broad applicability for accuracy assessment, they have limitations in quantifying resampling errors caused by map projections. This is due to the structural uncertainty with regard to the placement and pattern of grids. It is also difficult to calculate the absolute amount of resampling error in each projection. As an alternative to traditional testing methods, the use of random points was investigated. Specifically, random point generation, resampling with spherical block search algorithms, resampling accuracy with a perfect grid, and resampling accuracy with eight projections were investigated and are discussed here. Eight global referencing methods were tested: the equal-area cylindrical, sinusoidal, Mollweide, Eckert IV, Hammer-Aitoff, interrupted Goode homolosine, integerized sinusoidal projections, and the equal area global gridding with a fixed latitudinal metric distance. The resampling accuracy with a perfect grid is about 75 percent. Results showed the sinusoidal and the integerized sinusoidal projections and equal-area global gridding to achieve the highest accuracies. 相似文献
5.
《制图学和地理信息科学》2013,40(3):145-149
The Defense Mapping Agency, the National Ocean Service, and the U.S. Geological Survey each has earned a reputation among respective user communities as a leader in producing quality data and map products that meet the highest standards. With the increased use of GIS, user communities are rapidly expanding and have now begun to overlap. With adoption of SDTS as a Federal Information Processing Standard, all federal agencies are required to use the SDTS domestically. There is additionally an emerging need to unify efforts in the development of international standards. Existing standards need to be harmonized and future standards activities need to be linked more closely. This paper reviews the roles of each agency in developing spatial data and standards for exchange and outlines leadership activities in standards development that are currently underway. 相似文献
6.
《制图学和地理信息科学》2013,40(2):132-138
Some inexpensive personal computers may be programmed to produce, at a nominal incremental cost, map projection graphics useful as educational tools. Programs have been developed to produce outline maps based on anyone of dozens of projections, in almost any aspect, at a size of up to 13.5 by 27.1 cm or 20.3 by 20.3 cm [5?by 10? in. or 8 by 8 in.]. They are printed in a dot-matrix format normally containing up to 320 by 768 dots, with alternatives of 640 by 768 or 960 by 576 dots. Available options include features such as interrupted projection, miscellaneous great or small circles, and Tissot indicatrices. The maps often require many hours to prepare, but the programs can run unattended after initial parameters have been entered. 相似文献
7.
Andrew Curtis 《制图学和地理信息科学》2013,40(2):177-178
National Geographic Society (NGS) has made several changes throughout the years in their choice of map projection for their world reference maps. The Van der Crinten I map projection was used from 1922 to 1988. Then, in 1988, it was replaced by the Robinson projection. Beginning in 1998, the Winkel Tripel became the map projection of choice for NCS' world maps. Given this change, cartographers and others who make maps may be interested in using the Winkel Tripel for custom applications. The goal of this paper is to show how Winkel Tripel's complex projection equations can be programmed using Visual Basic. Those who use other languages such as C++ can use this programming example to help them create a similar algorithm in their language of choice. 相似文献
8.
《制图学和地理信息科学》2013,40(2):79-88
The Robinson projection is one of the most preferred projections for world reference maps in atlas cartography. The projection is constructed from Robinson's look-up table since there are no analytical formulas. This deficiency has led to a number of requests for the plotting formulas to which cartographers have responded by deriving analytical equations using different interpolation algorithms applied to Robinson's table values. The Robinson projection was examined with regard to its deformations calculated by four different algorithms, including the multiquadratic method. The numerical evaluations were then used to compare the algorithms. Solutions have been presented including some criticisms about this projection. The latitudes along which the scale is true and on which the maximum angular distortion equals zero have been determined. 相似文献
9.
《制图学和地理信息科学》2013,40(1):39-50
For half a century all cartography in the Soviet Union has been under centralized control. It was recognized early that mapmaking was an activity of prime importance. All phases of the activity—from cartographic education and the preparation of topographic and thematic maps to the development of regional atlases and school maps—have been managed by and for the benefit of the state in accordance with its economic and social objectives. This has had a significant effect on the development of cartography, the degree of its standardization, and the relative emphasis placed on its various aspects. 相似文献
10.
《制图学和地理信息科学》2013,40(2):131-147
Part of a cuboctahedron-based geodesic map projection by Buckminster Fuller is expanded to spherical quadrilaterals with opposite sides equal. Points on such a quadrilateral can be described by intersections of geodesics, which provide parameterized coordinate values in a Geodesic Coordinate System. Through a linear transform of the geodesic coordinates, a spherical quadrilateral maps to a parallelogram. The resulting map has the same constant scale on all four sides. Within the map, all lines parallel to the sides correspond to geodesics on the globe. Spherical rectangles, spherical squares, and diamonds (spherical rhombi) are specifically examined; various tiling sets of diamonds can be used to cover the globe. Non-projection applications in geometry, astronomy, and computer graphics are described. 相似文献