Groupers on the Edge: Shelf Edge Spawning Habitat in and Around Marine Reserves of the Northeastern Gulf of Mexico

The northeastern Gulf of Mexico contains some of the most diverse and productive marine habitat in the United States. Much of this habitat, located on the shelf edge in depths of 50 to 120 m, supports spawning for many economically important species, including groupers. Here, we couple acoustic surveys with georeferenced videography to describe the primary spatial and geologic features of spawning aggregation sites for four economically important species: gag (Mycteroperca microlepis), scamp (M. phenax), red grouper (Epinephelus morio), and red snapper (Lutjanus campechanus), with notes on fish distribution and abundance and spawning activities. We provide information on movement patterns of reef fish determined using acoustic telemetry. Finally, we discuss the possible coupling of geomorphology with hydrographic features to influence the overall productivity of the region and the importance of spatial fishery management in sustaining that productivity.     

Same space – different perspectives: comparative analysis of geographic context through sketch maps and spatial video geonarratives

ABSTRACT

The importance of including a contextual underpinning to the spatial analysis of social data is gaining traction in the spatial science community. The challenge, though, is how to capture these data in a rigorous manner that is translational. One method that has shown promise in achieving this aim is the spatial video geonarrative (SVG), and in this paper we pose questions that advance the science of geonarratives through a case study of criminal ex-offenders. Eleven ex-offenders provided sketch maps and SVGs identifying high-crime areas of their community. Wordmapper software was used to map and classify the SVG content; its spatial filter extension was used for hot spot mapping with statistical significance tested using Monte Carlo simulations. Then, each subject’s sketch map and SVG were compared. Results reveal that SVGs consistently produce finer spatial-scale data and more locations of relevance than the sketch maps. SVGs also provide explanation of spatial-temporal processes and causal mechanisms linked to specific places, which are not evident in the sketch maps. SVG can be a rigorous translational method for collecting data on the geographic context of many phenomena. Therefore, this paper makes an important advance in understanding how environmentally immersive methods contribute to the understanding of geographic context.     

Measured and perceived visual complexity: a comparative study among three online map providers

We present a study on human perception of map complexity, with the objective of better understanding design decisions that may lead to undesirable levels of complexity in web maps. We compare three complexity metrics to human ratings of complexity obtained through a user survey. Specifically, we use two algorithmic approaches published by others, which measure feature congestion (FC) and subband entropy (SE), as well as our own approach of counting object types rather than individual objects. We compare these metrics with each other as well as with human complexity ratings for three maps of the same area from map providers Google Maps, Bing Maps, and OpenStreetMap. Each map design is assessed at three different scales (levels of detail). We find that (1) the FC and SE metrics appear to be adequate predictors of what humans consider complex; (2) object-type counts are slightly less successful at predicting human-rated complexity, implying that clutter is more important in perceived complexity than diversity of symbology; and (3) generalization choices do impact human complexity ratings. These findings contribute to our understanding of what makes a map complex, with implications for designing maps that are easy to use.     

乡镇规划制图的探讨

本文对地图制图如何为城乡规划与建设服务进行了初步探讨。重点放在乡镇规划图的选题上,应从点和面两个不同方面进行考虑。     

网络地图集成于 GIS桌面系统的方法及试验

网络地图可以快捷地提供海量空间数据,用户可通过其提供的API方便地将其嵌入到定制的网络应用中,同样,将其集成到功能丰富的GIS桌面系统中是必要的、有益的.但目前主流的网络地图如Google地图、Bing地图等,与主流GIS桌面系统所支持的OGC的WFS、WMS、WCS等空间数据服务发布规范不兼容,因而不能被GIS桌面系...     

结合多混沌映射和输出反馈的图像加密算法

提出了一种结合多个Logistic混沌映射和逐段正弦混沌映射的图像加密算法。通过m个Logistic混沌映射的多次迭代,分别产生m个分段正弦混沌映射的初值和参数值,由m个分段正弦混沌映射迭代产生图像加密密钥序列,并引入密文输出反馈机制,对图像像素值逐点进行2轮异或加密。实验表明,该算法使密文对明文和密钥都充分敏感,加密图像像素值具有类随机均匀分布特性,相邻像素具有零相关特性,而且算法具有密钥空间大、加密速度快的优越性。     

区域地质图空间数据库建设技术方法及操作技巧

区域地质图空间数据库建设是地质调查成果数字化、信息化及数字国土工程的重要组成部分,为我国基础经济建设提供重要的数据支撑.以1：25万铁岭幅地质图空间数据库建设为例,对空间数据库建设标准及模型进行了阐述,并总结了地质图空间数据库的建设流程以及在属性操作过程中的一些技巧,以此为利用RGMAP系统建立数据库提供借鉴.     

浅谈北京规划市区1:500地形图数字化测绘

地形图为国民经济建设和社会各行各业的发展提供测绘保障,它是城市规划设计、市政工程建设、工业与民用建筑、土地开发利用、防灾减灾等各方面的基础数据之一。本文结合北京城市基础测绘工作,以《BSCS G2000》测图软件为例,简述大比例尺数字化地形图的作业流程,地形要素取舍及检查验收工作。     

数字技术背景下地图产品的变革

电子地图一边吸收传统地图学理论的精髓,同时引进新的技术和方法,摆脱了传统地图制图的局限和束缚,成为一种地理学研究与应用的新的语言形式。通过对传统地图同电子地图产品的比较来阐述地图产品在数字技术背景下产品模式、制图技术及应用领域等方面的变革。     

基于VB.NET的地形图编号查询与面积计算程序

主要介绍利用Microsoft Visual Basic.NET编写的地形图分幅编号查询与面积计算程序。通过该程序,根据经纬度坐标或高斯坐标,可查询该点所在各种基本比例尺下的图幅编号、西南图廓点的经纬度坐标以及在不同坐标系下的图幅面积。