Broad scale forest cover reconstruction from historical topographic maps

Land cover change is one of the major contributors to global change, but long-term, broad-scale, detailed and spatially explicit assessments of land cover change are largely missing, although the availability of historical maps in digital formats is increasing. The problem often lies in efficiency of analyses of historical maps for large areas. Our goal was to assess different methods to reconstruct land cover and land use from historical maps to identify a time-efficient and reliable method for broad-scale land cover change analysis. We compared two independent forest cover reconstruction methods: first, regular point sampling, and second, wall-to-wall mapping, and tested both methods for the Polish Carpathians (20,000 km²) for the 1860s, 1930s and 1970s. We compared the two methods in terms of their reliability for forest change analysis, relative to sampling error, point location and landscape context including local forest cover, area of the spatial reference unit and forest edge-to-core ratio. Our results showed that the point-based analysis overestimated forest cover in comparison to wall-to-wall mapping by 1–3%, depending on the mapping period. The reasons for the differences were mainly the backdating approach and map generalisation rather than the point grid position or sampling error. When we compared forest cover trajectories over time, we found that the point-based reconstruction captured forest cover dynamics with a comparable accuracy to the wall-to-wall mapping. More broadly, our assessment showed that historical maps can provide valuable data on long-term land cover trends, and that point-based sampling can be an efficient and accurate way to assess forest area and change trends. We suggest that our point-based approach could allow land cover mapping across much of Europe starting in the 1800s. Our findings are important because they suggest that land cover change, a key component of global change, can be assessed over large areas much further back in time than it is commonly done. This would allow to truly understand path dependencies, land use legacies, and historical drivers of land cover change.     

基于社会地图的东莞市社会空间研究

既有社会空间研究以社会区研究居多,主要基于社会区理论和因子生态分析方法,较多考虑分析对象的社会属性而非空间特征,对社会空间的空间侧面刻画不足,其分析结果也常常被聚类人口的数据特征所左右。本文尝试基于社会地图方法,以人口普查数据和社会设施机构POI数据首先进行社会空间属性的归纳,制作社会地图,并以此为基础,采用归纳的方法渐进探索中国城市社会空间的特征。具体以东莞市为例,通过社会地图归纳方法将东莞市划分为3大类、11小类社会空间,并具体解析了多种社会空间要素组合类型。和既有基于社会区的分析结果相比,本文对各类社会要素在城市空间上的分布及其组合特征描述更为精细,其结果对认识中国社会空间特质及其后的社会空间政策制定更具参考意义。本文认为,基于社会地图的社会空间研究,有助于自下而上地发现有别于西方的中国城市社会空间特征和结构,也有助于建立基于中国的社会空间理论,值得进一步推广和尝试。     

Mapping the Geographical Diffusion of a Finnish Smallpox Epidemic from Historical Population Records

Smallpox mortality from an early 19th century epidemic in Finland is mapped at the parish village level. First, geographically referenced historical materials are used to construct a map showing the spread of smallpox mortality among villages. Next, the diffusion of smallpox morbidity is simulated by computer for the same set of villages. These two maps are then compared. Results indicate that at this scale maps of mortality diffusion can show general trends but have no direct spatial correspondence to the underlying pattern of morbidity diffusion. Mortality maps cannot be used as a surrogate measure of infectious contact behavior at micro scales of analysis.     

Mapping the Geographical Diffusion of a Finnish Smallpox Epidemic from Historical Population Records

Smallpox mortality from an early 19th century epidemic in Finland is mapped at the parish village level. First, geographically referenced historical materials are used to construct a map showing the spread of smallpox mortality among villages. Next, the diffusion of smallpox morbidity is simulated by computer for the same set of villages. These two maps are then compared. Results indicate that at this scale maps of mortality diffusion can show general trends but have no direct spatial correspondence to the underlying pattern of morbidity diffusion. Mortality maps cannot be used as a surrogate measure of infectious contact behavior at micro scales of analysis.     

近代以来江苏沿海滩涂围垦历史演变研究

近百年来江苏沿海进行了大规模的滩涂围垦开发。本研究评估了近代以来江苏沿海滩涂围垦历史演变情况,分析其演变机理。研究搜集整理了清末至今多种历史地形图、地方志、遥感资料,利用统计分析以及空间分析,定量地揭示近百年来江苏沿海围垦时空变化,并简要分析变化背后的机理。研究结果表明：（1）在围垦的时间分布上,不同时期的历史围垦程度不同,其中民国时期1910 年代和解放以后的1950 年代的围垦规模分别为解放前和解放后的两个围垦高峰时期;（2）在围垦的空间分布上,总的来说,盐城市围垦面积最大,总量占全省总围垦面积近70%,南通、连云港市相对较少,而沿海三市围垦面积排名前五名的分别是大丰市、射阳县、连云区、响水县、如东县;（3）从围垦特点看,空间缓冲区分析显示历史上江苏沿海围垦多为鱼鳞似的圈围,用途则以农业生产、水产养殖、国营盐场为主,工业用地、港口建设用地大大不足,用地综合效益不高。     

南粤古驿道红色寻踪——基于《寻乌调查》的历史地理分析

基于毛泽东同志所作的《寻乌调查》,利用历史地图资料,结合当前遥感影像数据、道路地名信息及相关历史资料等,运用GIS技术对历史资料进行还原处理,从交通区位、经济地理与区域文化等方面,对20世纪30年代寻乌与南粤的区域历史地理关系进行研究：1）还原并佐证了《寻乌调查》描述的区域交通系统,梳理出寻乌与南粤区域水陆交通网络及交通运输的基本特征,寻乌典型的边区区位与自然地理等条件,成就了其联系南粤的交通枢纽功能。2）寻乌与南粤的区域经济地理关系具有典型的“盐上米下”特征;寻乌在区域贸易流通中承担着中转站的功能,但边区市集发展程度较低,寻乌的社会经济深受以梅县为腹地的南粤地区发展的影响。3）南粤革命力量对中央苏区具有不可磨灭的历史贡献,红色文化底蕴非常深厚。理解寻乌与南粤的区域历史地理关系,既对当前的区域发展规划与政策制定具较强的指导作用,也为当前的南粤古驿道活化和开发提供了一条“寻乌调查红色之旅”路线。     

Automatic alignment of contemporary vector data and georeferenced historical maps using reinforcement learning

ABSTRACT

With large amounts of digital map archives becoming available, automatically extracting information from scanned historical maps is needed for many domains that require long-term historical geographic data. Convolutional Neural Networks (CNN) are powerful techniques that can be used for extracting locations of geographic features from scanned maps if sufficient representative training data are available. Existing spatial data can provide the approximate locations of corresponding geographic features in historical maps and thus be useful to annotate training data automatically. However, the feature representations, publication date, production scales, and spatial reference systems of contemporary vector data are typically very different from those of historical maps. Hence, such auxiliary data cannot be directly used for annotation of the precise locations of the features of interest in the scanned historical maps. This research introduces an automatic vector-to-raster alignment algorithm based on reinforcement learning to annotate precise locations of geographic features on scanned maps. This paper models the alignment problem using the reinforcement learning framework, which enables informed, efficient searches for matching features without pre-processing steps, such as extracting specific feature signatures (e.g. road intersections). The experimental results show that our algorithm can be applied to various features (roads, water lines, and railroads) and achieve high accuracy.     

Geopolitical Legacies and Central European Export Linkages: A Historical and Gravity Model Analysis of Hungary

This paper analyzes Hungary's export linkages of the interwar and Cold War periods using gravity model and historical analyses. Hungary is a useful example of former Soviet satellites because it combines relative political stability (since 1956) and experimentation with the New Economic Mechanism (NEM) during the 1970s and 1980s. Historical analysis reveals seven events since World War I that changed Hungary's trade patterns. Gravity model analysis for 1955, 1965, 1975, and 1985 shows the dramatic cleavage of the “Iron Curtain,” the effect of the NEM, and particularly strong and weak linkages for Hungarian trade that may result from historical legacies, complementarity, or specific political contacts.     

A Method for Assessing the Planimetric Accuracy of Historical Maps: The Case of the Colorado-Green River System*

The position of linear elements on historical maps can be digitized and numerically compared with similar features on modern maps. This allows for the evaluation of amounts and rates of improvement in cartographic accuracy and of the primary sources used for the generation of subsequent maps. A case study of the Colorado-Green River system illustrates the method and documents the pace of improvement in the cartographic depiction of the river system as a function primarily of the historical pressures of westward expansion.     

Geopolitical Legacies and Central European Export Linkages: A Historical and Gravity Model Analysis of Hungary

This paper analyzes Hungary's export linkages of the interwar and Cold War periods using gravity model and historical analyses. Hungary is a useful example of former Soviet satellites because it combines relative political stability (since 1956) and experimentation with the New Economic Mechanism (NEM) during the 1970s and 1980s. Historical analysis reveals seven events since World War I that changed Hungary's trade patterns. Gravity model analysis for 1955, 1965, 1975, and 1985 shows the dramatic cleavage of the “Iron Curtain,” the effect of the NEM, and particularly strong and weak linkages for Hungarian trade that may result from historical legacies, complementarity, or specific political contacts.     

Land Classification Maps of Areas Basic to Agricultural Production

Abstract

Einevoll, O. 1968. Land Classification Maps of Areas Basic to Agricultural Production. Norsk geogr. Tidsskr. 22, 264–270.

In Norway, a detailed land survey, based on photogrammetry, is now proceeding for land classification maps of the scale 1:5,000 (for certain minor areas 1:10,000) covering agricultural areas and including forest land. The areas to be mapped are classified according to land capability and general conditions of management. Containing a great deal of additional information as well, these maps will serve as a valuable aid in land use planning. The survey is designed to be completed in 12–15 year's time.

More roughly designed maps for the entire country on the scale 1:100,000 and 1:250,000, printed in colour, will be produced within two years' time. Intermediate maps of 1:20,000, containing an extended number of land types, will be undertaken gradually, after the appearance of the large scale map series. Property boundaries recorded in connexion with the surveying for the large scale maps will serve as the basis for a complete land register containing exact information about size and land properties of individual holdings.     

清末以来洞庭湖区通江湖泊的时空演变

本文利用清光绪22年以来17个时段的多种历史地图和航天航空遥感数据,采用遥感解译、数据统计分析与历史对比方法,分析清末以来洞庭湖区通江湖泊面积的时序变化,探究空间演变特征。结合水利部门发布的典型年份监测数据,检验了遥感获取的湖泊面积精度,误差仅为0.62%。结果显示：洞庭湖通江湖泊面积从1896年的5216.37 km²减少到2019年的2702.74 km²,萎缩率为48.19%。1949年前的53年为明显萎缩期,年均萎缩15.66 km²;20世纪50年代为陡崖式萎缩期,年均萎缩139.05 km²;20世纪60—70年代为快速萎缩期,年均萎缩21.66 km²;1980年以来为基本稳定期,年均萎缩0.13 km²,面积仅减少了5.10 km²。就具体湖泊而言,东洞庭湖是各通江湖泊中面积萎缩最大的湖泊,减幅为922.60 km²;其次是目平湖,减幅为588.05 km²;再次是南洞庭湖,减幅为448.37 km²;七里湖的面积变化很小,但经历了先扩张后萎缩的过程。1998—2002年实施“退田还湖”工程,洞庭湖面积增加了10.50 km²。总体而言,清末以来洞庭湖区通江湖泊的演变主要表现为大通湖的封闭析出、整修南洞庭湖的湖垸置换与南迁、围垦西洞庭湖的局部残存、东洞庭湖的三面合围以及1998年特大洪灾后有限的“退田还湖”。本文为长江流域生态修复和环境保护战略提供了客观资料和技术支撑。     

中非农产品贸易强度及其国际地位演变分析

近年来中国和非洲农业合作日渐频繁,中非农产品贸易也逐渐受到学术界的广泛关注,中非农产品贸易在全球中的横向对比、中国与非洲各国之间的横向对比研究也显得尤为重要。为掌握在全球背景下中非农产品贸易关系及强度的历史状况,利用FAOSTAT中的农产品贸易数据,对中非农产品贸易与其他国家或地区农产品贸易展开横向对比,并对中国与非洲各国之间贸易强度的历史变化进行系统分析。研究结果显示：1）尽管非洲农产品进出口贸易额不断上升,但在世界贸易中的份额持续徘徊在低位,并无显著变化;2）中非之间的贸易关系在1986-2013年间的变化并不突出,欧美仍是其主要的贸易伙伴;3）大多数非洲国家对华年次贸易频率低且贸易量小;4）南非、坦桑尼亚、埃塞俄比亚、马里、尼日利亚、阿尔及利亚、马达加斯加、毛里塔尼亚和尼日尔等国不仅拥有较多农用地资源,且具有较好的对华农业贸易的历史基础。     

MAPPING KENTUCKY'S FRONTIER TRAILS THROUGH GEOGRAPHICAL INFORMATION AND CARTOGRAPHIC APPLICATIONS*

Historical first‐generation frontier roads in America's trans‐Appalachian West often evolved from buffalo and Indian trails into pioneer routeways such as Daniel Boone's Trace and, eventually, into twentieth‐century hard‐surface highways. Period cartographers found these routes difficult to document accurately, and present‐day scholars often depict them only on small‐scale maps, which simply illustrate connections between origin and destination points. Accurately mapping Kentucky's first‐generation roads at large scale requires detailed site and contextual topographic information over long distances, but historical maps, diaries, surveyors' reports, and other period documents often lack sufficient detail for route‐related sites to support mapping. Use of gis software enables positioning historical routes onto U.S. Geological Survey contour‐ and hill‐shaded base maps by mapping verifiable locations and linking them through interpretation of best‐choice routes that consider frontier migrants' transportation priorities, such as direction, distance, gradient, and land‐surface character.     

商圈划分中多元市场域的界定与实证

对商业设施的商圈进行科学识别与划分是分析其商业前景、优化商业空间结构的基础。本研究首先提炼和界定了商圈划分的两种类型、四种市场域方法,分别是基于到访比例的邻近型与份额型市场域、基于出行概率的共享型和首位型市场域,通过比较其优劣发现这四种视角仅能反映商圈的某一特征,无法刻画出商圈空间分布全貌。据此,尝试提出了一种新的复合型市场域模型,并应用手机信令数据,以上海市商业中心为例,对其商圈划分进行了实证检验。研究发现：复合型市场域模型可以综合反映空间距离、客流规模和惠顾概率等要素对商圈的影响,可以弥补单一市场域视角下商圈划分方法的不足。与传统邻近型相比,基于复合市场域模型识别划分的商圈不仅重叠度低,而且其空间分布更加符合实际。     

我国《地方病与环境图集》编制研究

《中华人民共和国地方病与环境图集》是一部展示人类疾病与生态环境关系的新型地图集。本文重点论述它的编制意义、原则、特点和方法。     

Compilation and evaluation of a small-scale land resource map

A small-scale land resource map was compiled by combining generalised large-scale maps with auxiliary data and interpreted satellite images. The large-scale maps covered areas below the treeline and were generalised using an expansion-contraction algorithm (ECA). Areas above the treeline were added by manual interpretation of a Landsat TM image (Band 4,5,3). Certain features were also copied from small-scale topographic maps. The thematic accuracy was evaluated individually for different segments of the map, according to the production technique. The general accuracy was satisfactory in areas where the ECA technique had been applied. Areas mapped using auxiliary data were rendered inaccurately both below and above the treeline, but the result was still found acceptable. The results from satellite interpretation above the treeline were promising, but need to be improved. The image interpretation can either be refined by using alternative sensors, by improved training of the interpreters, or by adjusting the definition of the land resource classes in order to attain a better match between the class definitions and the result of the classification.     

中国企业出口动态的空间差异性

对于企业出口动态的研究有助于更好地理解支撑贸易增长、贸易方式结构变化的机制。本文描述近年来中国企业出口动态的空间格局,并从地方出口多样性的角度解释出口动态的空间差异性。研究发现,在2003—2011年,中国企业出口动态在时间上呈现从高速增长到稳定增长的变化特征;空间上表现出地区集聚特征,贸易高进入型地区呈现出从沿海向内陆转移的趋势,且在一般贸易企业中更为明显。中国企业出口动态受到产品出口多样性和市场出口多样性影响,产品出口多样性主要依靠信息发现效应提升地方企业出口市场进入率,并不能阻止企业退出出口市场;市场出口多样性不能促进企业进入出口市场,但可抑制在位企业退出市场,且这种风险分散效应对于一般贸易更强。此外,对于能够在多次或持续出口的企业而言,出口产品相关多样性能够降低地方企业出口退出率,表明出口学习效应的效果可能与企业参与出口的时间有关。     

蒙古国省级行政单元投资环境评价与投资对策研究

蒙古国作为中国的邻国,两国之间的资源和产业互为补充,贸易合作前景广阔。选择最佳区位和产业来加强对蒙古国的投资,对促进中蒙俄经济走廊建设具有重大战略意义。但是目前研究较为有限,存在着投资环境不明确,投资风险未知,严重限制了对蒙投资和贸易合作。本研究团队对蒙进行了十数年科学考察研究,获得了大量一手调研数据。根据对调研数据及蒙古国区域政策的分析,本研究构建了投资环境评估模型ESE-PRT模型,从经济、社会、生态、资源、交通、政策等方面科学评估了蒙古国22个省级行政单元投资环境,划分了四类投资区,进一步揭示了优先投资区的投资优先产业及主要的投资风险,并针对蒙古国投资环境提出了相应的投资对策。本研究结果将为蒙古国重点投资区位选择、中资企业海外布局及中蒙双边经贸合作提供科学支撑,并将对中蒙俄经济走廊建设具有重要的现实促进意义。     

世界油棕生产贸易的时空格局演变及发展预测

油棕是世界上单位面积产量最高的一种木本油料作物,有“世界油王”之称。它的产量和贸
易量比重在植物油料中居世界第一,经济效益巨大。本文从世界油棕的起源与地理扩散入手,对近
年来世界油棕的生产贸易现状作了分析,结果表明：油棕起源于非洲,扩散到亚非拉广大热带地
区,目前形成中西非、东南亚、中南美三大产区和印、中、欧盟等十大消费地的基本格局。在此基础
上,对油棕生产贸易的发展趋势作了预测,一是种植面积和油棕消费市场将会继续增长;二是新科
技助力油棕的增产;三是油棕的可持续利用必将进一步加强。