基于改进Web墨卡托投影的瓦片地图服务设计与实现

为解决网络地理信息应用二、三维一体化显示需要,通常做法是处理并存储两套不同投影的地图瓦片数据,一套采用Web墨卡托投影,面向二维地图应用;一套采用经纬度坐标,面向三维地图应用。这在一定程度上降低数据处理效率、浪费存储资源。文中提出一种改进Web墨卡托地图投影方法,并设计一种面向影像地图和DEM数据的瓦片化方法。方法生成的影像地图瓦片数据既能同时面向二维地图和三维可视化场景使用,又有效解决Web墨卡托投影不支持高纬度地区栅格地图表达的缺陷。将新型的地图投影和数据模型通过瓦片地图服务系统进行验证,证明这种新改进的投影和影像,以及DEM瓦片化方法具备较高的实用性。     

分布式多源处理集成的地学工作流脚本方法

针对地学空间信息基础设施迫切需要能够集成多源地理信息处理软件包与分布式空间信息网络服务的工作流软件,以帮助用户构建复杂的处理流程,实现从数据、信息到知识转换的现状,该文提出了一种分布式多源处理功能集成的地学工作流脚本方法。利用脚本来连接不同地理信息处理软件中的功能,并通过工作流自动生成技术来构建复杂的空间信息处理流程,以实现对数据处理与分析能力的提高。通过扩展地学工作流建模工具——GeoJModelBuilder,在空间信息服务组合的基础上集成地理信息处理软件,实现了多源处理功能集成的原型系统,并以从数字高程模型中提取水文模型为例来证明该方法的可行性。     

基于Web Service的地图符号库的设计与实现

研究了C/S结构和B/S结构的特点,根据不同平台的客户端对地图操作的要求,提出了一种基于WebService的分布式框架结构,实现了不同客户端的跨平台互操作。根据面向对象的要求对符号库进行了图素和结构设计,建立了一种基于WebService的面向对象的读取符号库的框架结构。指出WebService是地图符号在多客户端可视化的最佳解决方案。     

Microzooplankton feeding impact in a coastal upwelling system on the NW Iberian margin: The Ría de Vigo

The dilution technique, combined with identification and enumeration of pico-, nano- and micro-plankton by microscopy, was used to estimate microzooplankton impact on the microbial community in surface waters of a coastal embayment on the NW Iberian upwelling system. Microzooplankton were important consumers of autotrophic and heterotrophic plankton in this system, feeding up to 93% of standing stock and more than 100% of production of several groups. Heterotrophic bacteria and heterotrophic picoflagellates experienced the highest and constant impact, with 75–84% of their standing stocks and 85–102% of their production being channelled through the microbial food web. Pico- and nano-phytoplankton were also consumed, although maximum grazing occurred on diatoms during upwelling events, coinciding with highest primary production. Predation on pico-nano-heterotrophs was especially relevant under downwelling conditions, when consumption of total carbon and particularly autotrophic carbon was considerably lower than during upwelling. The results suggest that the existence of a multivorous food web, extending from the microbial loop to the herbivorous food web, could be a major feature in this coastal upwelling system. The microbial loop, which occurs as a permanent background in the system, would contribute to sustain the microbial food web during downwelling, whereas the herbivorous food web could coexist with a microbial food web based on large diatoms during upwelling. The multivorous food web would partially divert diatoms from sinking and hence favour the retention of organic matter in the water column. This could enhance the energy transfer to higher pelagic trophic levels in coastal upwelling systems.     

Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central HAUSGARTEN station (2500 m) based on an empirical data set consisting of data on biomass, prokaryote production, total carbon deposition and community respiration. The model resolved 99 carbon flows among 4 abiotic and 10 biotic compartments, ranging from prokaryotes up to megafauna. Total carbon input was 3.78±0.31 mmol C m⁻² d⁻¹, which is a comparatively small fraction of total primary production in the area. The community respiration of 3.26±0.20 mmol C m⁻² d⁻¹ is dominated by prokaryotes (93%) and has lower contributions from surface-deposit feeding macro- (1.7%) and suspension feeding megafauna (1.9%), whereas contributions from nematode and other macro- and megabenthic compartments were limited to <1%. The high prokaryotic contribution to carbon processing suggests that functioning of the benthic food web at the central HAUSGARTEN station is comparable to abyssal plain sediments that are characterised by strong energy limitation. Faunal diet compositions suggest that labile detritus is important for deposit-feeding nematodes (24% of their diet) and surface-deposit feeding macrofauna (∼44%), but that semi-labile detritus is more important in the diets of deposit-feeding macro- and megafauna. Dependency indices on these food sources were also calculated as these integrate direct (i.e. direct grazing and predator–prey interactions) and indirect (i.e. longer loops in the food web) pathways in the food web. Projected sea-ice retreats for the Arctic Ocean typically anticipate a decrease in the labile detritus flux to the already food-limited benthic food web. The dependency indices indicate that faunal compartments depend similarly on labile and semi-labile detritus, which suggests that the benthic biota may be more sensitive to changes in labile detritus inputs than when assessed from diet composition alone. Species-specific responses to different types of labile detritus inputs, e.g. pelagic algae versus sympagic algae, however, are presently unknown and are needed to assess the vulnerability of individual components of the benthic food web.     

基于支持向量机与余弦夹角法的中文网页过滤的研究与设计

为了进一步准确过滤对青少年危害较大的色情网页,在汉语词法分析系统添加去禁用词功能实现中文分词,通过改进的词频-逆文档频率及文档频率-互信息方法完成特征提取,从而实现基于支持向量机的过滤方案。并在给出的余弦夹角公式的基础上,提出了一种基于余弦夹角法的中文网页过滤方案。结合两种方案,实验证明在统一资源符总库存在条件下方案对色情等网页过滤效果进一步提高。     

网络地图服务中空间查询与分析的栅格化实现

地理信息获得了越来越广泛与深入的应用.空间查询与空间分析是GIS(Geography Information System,地理信息系统)的核心特征之一,也是空间信息服务(如Web Feature Service)实现中的关键问题.如何在网络地图服务场景下提供高效能的空间查询与空间分析功能是网络地图服务器设计与实现中的...     

基于JAVA的WEB树形动态报表设计及应用

介绍了一个基于Java的Web树形动态报表系统。系统将报表定义为树形结构，可由用户构建报表树结构的树枝和树叶，从而提高报表的灵活性。应用本系统可大大地缩短开发Web项目的周期，提高工作效率。     

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.