The Equal Earth map projection

The Equal Earth map projection is a new equal-area pseudocylindrical projection for world maps. It is inspired by the widely used Robinson projection, but unlike the Robinson projection, retains the relative size of areas. The projection equations are simple to implement and fast to evaluate. Continental outlines are shown in a visually pleasing and balanced way.     

多投影间地图投影变换实现的途径与优化

针对多种地图投影间自由变换的需求 ,综合对比地图投影变换的主要方法及其特点 ,该文认为反解变换是解决多种投影间投影变换的最佳途径。以此为基础 ,具体探讨了地图投影变换计算机实现的主要过程 ,讨论了地图投影体系、投影参数、算法优化和误差控制等投影变换计算机实现中的关键问题     

A compromise aspect-adaptive cylindrical projection for world maps

There are two problems with current cylindrical projections for world maps. First, existing cylindrical map projections have a static height-to-width aspect ratio and do not automatically adjust their aspect ratio in order to optimally use available canvas space. Second, many of the commonly used cylindrical compromise projections show areas and shapes at higher latitudes with considerable distortion. This article introduces a new compromise cylindrical map projection that adjusts the distribution of parallels to the aspect ratio of a canvas. The goal of designing this projection was to show land masses at central latitudes with a visually balanced appearance similar to how they appear on a globe. The projection was constructed using a visual design procedure where a series of graphically optimized projections was defined for a select number of aspect ratios. The visually designed projections were approximated by polynomial expressions that define a cylindrical projection for any height-to-width ratio between 0.3:1 and 1:1. The resulting equations for converting spherical to Cartesian coordinates require a small number of coefficients and are fast to execute. The presented aspect-adaptive cylindrical projection is well suited for digital maps embedded in web pages with responsive web design, as well as GIS applications where the size of the map canvas is unknown a priori. We highlight the projection with a height-to-width ratio of 0.6:1, which we call the Compact Miller projection because it is inspired by the Miller Cylindrical projection. Unlike the Miller Cylindrical projection, the Compact Miller projection has a smaller height-to-width ratio and shows the world with less areal distortion at higher latitudes. A user study with 448 participants verified that the Compact Miller – together with the Plate Carrée projection – is the most preferred cylindrical compromise projection.     

基于面向对象的地图投影转换模块设计

以基于面向对象的方法实现地图投影转换模块设计,探讨该方法在地图投影转换中以及具体投影转换模块的设计及实现,在VC6.0平台下通过相关接口的建立以及地理坐标系和投影坐标系两大主要类的设计和扩充,实现地理坐标系间、投影坐标系间或两者间的投影转换.该模块有利于快速、高效编程的实现,并具有扩展性强和易于维护等优势.     

多焦点地图投影

现在有些地图有这样的要求，即在一幅地图中，投影中心附近比例尺应较大，边缘部分可以较小，甚至相差几倍，以能详细地显示投影中心附近的地物。为了解决这个问题，曾有^拟定了辐射一变比侧尺投影，即自投影中心向四周辐射以显示其变化。本文在说明了辐射一变比侧尺投影的基础上，阐明了多焦点投影，其投影中心有若干个，各向其四周辐射，这就能更好地显示各地地物的变化。     

A new pseudocylindrical equal-area projection for adaptive composite map projections

The recently introduced adaptive composite map projection technique changes the projection to the geographic area shown on a map. It is meant as a replacement for the commonly used web Mercator projection, which grossly distorts areas when representing the entire world. The original equal-area version of the adaptive composite map projection technique uses the Lambert azimuthal projection for regional maps and three alternative projections for world maps. Adaptive composite map projections can include a variety of other equal-area projections when the transformation between the Lambert azimuthal and the world projections uses Wagner’s method. To select the most suitable pseudocylindrical projection, the distortion characteristics of a pseudocylindrical projection family are analyzed, and a user study among experts in the area of map projections is carried out. Based on the results of the distortion analysis and the user study, a new pseudocylindrical projection is recommended for extending adaptive composite map projections. The new projection is equal-area throughout the transformation to the Lambert azimuthal projection and has better distortion characteristics then small-scale projections currently included in the adaptive composite map projection technique.     

A New Method for Finding Geographic Centers,with Application to U.S. States

The geographic center of a region is a fundamental geographic concept, and yet there is no commonly accepted method for its determination. This article discusses some of its history as well as its definition and calculation, and a new method for its calculation is suggested. The new method minimizes the sum of squared great circle distances from all points in the region to the center. This entails (1) projecting regional boundary points using an azimuthal equidistant projection, (2) finding the geographic center of the projected two-dimensional region, and (3) then transforming this location back to a latitude and longitude. This new approach is used to find the geographic center of the contiguous United States and to provide a new list of the geographic centers for U.S. states. This list improves on the widely used but inaccurate list published by the United States Geological Survey in 1923.     

城市洪涝易损性分类与诊断研究

城市洪涝易损性分析对城市防洪安全具有极其重要的作用。将基于加速遗传算法的投影寻踪模型应用于城市洪涝易损性分类与诊断。运用建议模型探讨了湖南省29个城市的洪涝易损性,将全省洪涝易损性程度划分为5个等级:低度易损性、较低度易损性、中度易损性、较高度易损性、高度易损性,同时与模糊评价结果进行了对比。研究表明,投影寻踪模型客观考虑了各个影响因子的权重,结果合理、可靠,可以在实际的类似问题中应用。     

Carbon emissions trends with optimal balanced economic growth of China and the USA and some abatement options for China

It is believed that the global CO2 emissions have to begin dropping in the near fu- ture to limit the temperature increase within 2 degrees by 2100. So it is of great concern to environmentalists and national decision-makers to know how the global or national CO2 emissions would trend. This paper presented an approach to project the future CO2 emissions from the perspective of optimal economic growth, and applied this model to the cases of China and the United States, whose CO2 emissions together contributed to more than 40% of the global emissions. The projection results under the balanced and optimal economic growth path reveal that the CO2 emissions will peak in 2029 for China and 2024 for the USA owing to their empirically implied pace of energy efficiency improvement. Moreover, some abatement options are analyzed for China, which indicate that 1） putting up the energy price will de- crease the emissions at a high cost; 2） enhancing the decline rate of energy intensity can significantly mitigate the emissions with a modest cost; and 3） the energy substitution policy of replacing carbon intensive energies with clean ones has considerable potential to alleviate emissions without compromising the economic development.     

基于投影寻踪回归技术的塔里木河水质模拟分析

利用投影寻踪回归技术（ＰＰＲ）进行水质评价是一种新方法。本文在现有水文观测资料基础上，通过ＰＰＲ分析，建立了塔里木河水质模型，并利用ＰＰＲ对影响河流水质的因素作了分析，可为流域水质管理和控制提供依据。     

Volume 111 Index

Abstract

Concepts related to alternative map projections can be difficult to explain to students given the diversity and complexity of available projections. Students frequently have trouble understanding how distortions caused by the choice of a projection can affect map readability and comprehension. Programs available for personal computers now provide geography and cartography instructors with a method for interactively educating students concerning the distortions associated with alternative map projections. Such software can be incorporated into laboratory assignments in introductory geography courses or in more advanced courses that deal with map design or thematic cartography.     

地理信息系统中图形数据的投影变换研究

投影变换是地理信息系统(GIS)中空间处理的重要环节, 根据GIS中图形数据操作与分析, 介绍投影变换的两种基本方法——反解变换法和数值交换法。反解交换法适用于两种投影的坐标公式较简单, 较易求出两种投影平面直角坐标之间直接联系的情况。数值变换法应用范围较广, 它可以避开较复杂的投影坐标公式的反解问题, 求出两个不同投影平面场上点的对应关系。     

基于地图方里网的全球剖分系统

针对现有剖分模型的不足,提出了一种基于地图方里网的全球剖分系统,有效避免了传统经纬度格网模型在高纬度地区的形状退化和正多面体格网模型的面片形状不规则问题。制定了相应的编码,实现了面片编码与传统地理坐标之间的转换和邻接关系的计算,最后对方里网在地球椭球面上的变形规律进行了研究。研究结果表明:基于地图方里网的剖分系统不仅具有科学的数据组织形式,而且面片单元的变形面积小、变形规律稳定。     

未来气候变暖情形下青藏高原多年冻土分布初探

基于未来温室气体中等排放情景下气候模式给出的气候预测结果的高分辨率降尺度分析结果,运用两种方法(年均温法和高程模型法)模拟了1980-1999,2030-2049和2080-2099年3个时段青藏高原多年冻土分布.结果表明,以年均地温-1℃作为多年冻土划分依据的年均温法模拟的目前(1980-1999年)高原多年冻土面积为127.99万km2,与世界数据中心给出的青藏高原现代多年冻土面积为129.12万km2的估算接近(误差率仅为0.86%);到本世纪中期(2030-2049年),高原多年冻土面积减少为87.26万km2,退化率达到31.82%;而到本世纪末(2080-2099年),高原多年冻土面积只有69.25万km2,较目前将退化45.89%.不同高度带的对比分析还发现,与高原及其邻近地区年均气温的升高一般随海拔高度而增加的趋势相反,未来高原多年冻土的退化率将随着海拔高度增加而降低.在全球变暖过程中的冻土退化,特别是高原东南部冻土向西北部的逐步退缩,对高原冻土区工程稳定性的影响应引起我们的足够重视.     

中国海洋渔业资源可持续利用的动态评价与空间分异

运用基于多智能体遗传算法的投影寻踪模型和核密度估计模型,对2003~2012年中国沿海11个省市（不含港澳台）海洋渔业资源可持续利用水平的时空格局演化进行测度。研究结果表明：从投影方向上看,捕捞技术、捕捞强度和渔业产业结构等,逐渐上升为影响海洋渔业资源可持续利用水平的重要因子;从时空格局上看,上海的海洋渔业资源可持续利用属于高水平区板块,天津、河北、江苏、浙江和广西属于中等水平区板块,辽宁、山东、福建、广东和海南属于低水平区板块;从总体上看,海洋渔业资源可持续利用呈现不可持续性,具体表现为时间演化可持续,空间演化不可持续,时空演化呈现出不可持续的两极分化趋势。未来高水平区板块应保持原来的发展模式,中等水平区板块的可持续利用路径选择是保中争高,低等水平区板块的可持续利用路径选择是追中攀高。     

海洋小比例尺地图精确测量及计算方法

针对传统的欧式测量方法在海洋小比例尺地图长度、面积等计算时存在精度差的问题,通过对WGS1984投影、墨卡托投影、兰勃托投影和阿尔伯斯投影等特性的研究,利用ArcEngine技术实现海洋小比例尺地图投影的精确测量及计算,论述在不规则地球椭球体下如何精确量算海洋距离、面积等信息,为我国海洋资源探测和军事战略方面提供基础服务.     

CMIP3气候模式对北疆气候变化模拟评估及未来情景预估

利用北疆地区1961～2000年气温、降水观测数据和CMIP3(phase 3of the CoupledModel Inter-comparison Project)提供的20个海气耦合模式在该地区的模拟结果,评估了各气候模式对北疆地区降水、气温的模拟效果。结果表明:各气候模式对气温、降水模拟效果差异较大。从对气候平均态的模拟来看,有5个模式对降水的模拟相对较好,2个模式对气温的模拟相对较好;所有模式均能模拟出气温的年内变化特征,其中MPI_ECHAM5模式结果与观测数据结果最为接近;但各模式对降水的模拟效果均较差。在月尺度上,一些模式结果与降水观测数据呈负相关性,但对于月气温,大多数模式与其相关性较好,且各模式间月气温均方根误差变化幅度相对较小。综合来看,大部分气候模式在该地区模拟能力比中国东部地区要弱;气候模式的降水数据包括多模式集合数据还不适合用于未来北疆地区降水变化预估分析。最后,采用累计分布函数法(CDF_S)仅对北疆地区2011～2050年时段的气温进行偏差校正与预估分析,结果表明未来40年北疆地区气温在三种排放情景下均呈上升趋势。     

长江流域粮食供求预测研究

长江流域是我国重要的农产品生产基地,粮食生产在我国占有十分重要的地位,历史上曾是我国粮食最大生产区域和商品粮的主要提供者。分析表明,２１世纪前期,长江流域粮食供求状况总体上仍将是供大于求。在２０００年、２０１０年和２０２０年流域粮食生产量比需求量分别多８７亿公斤、２３１亿公斤和３３０亿公斤。这说明作为一个整体的长江流域的商品粮区域性质不会发生改变,在近二、三十年内仍将是我国粮食的主产区和粮食调出区