地理信息系统文献翻译——摘要：许多类型的地图上可以在一个连续的表面通过邻域操作来创建，例如提供的数字高程模型。这些最常用的包括一阶导数的斜坡或坡向，二阶导数平面曲率或剖面曲率。这些变量通常用于在地形地貌分析。一阶导数也提供了对晕渲图的细微增强功能。例如，一些地图结合倾斜的和垂直的光照，后者反映了不同坡度。

这项研究说明了二阶导数图如何结合地形晕渲来增强地形细节。一个简单的锥模型表明，色调图像的边缘斜坡或坡向的变化小于0.5°的在曲率地图上是可见的。地形晕渲图像结合曲率增强色调边缘的连续性，特别是在强烈的光照的区域。平面曲率和剖面曲率的变化似乎是有效的突出收敛和发散水系和沉积单元之间侵蚀率的变化。考虑到光照模型的遮光曲率可以为晕渲的地形图添加细节以一种类似于由地图浏览器使用的认知模式的方法。

关键词：平面曲率、剖面曲率、光照、晕渲、制图、地理可视化

1.引言

地貌学家和制图人员都采用由高程数据的量化地形表面的形状或结构导出的变量。这项研究着重在于从局部操作计算的变量的制图表达直接地从地形学数据，威尔逊和格兰特曾讨论的“主要属性（关键字）”。同时强调把地形看作连续函数f（x，y，z）计算一阶导数和二阶导数的方法。

一阶导数包括坡度和坡向。坡度，垂直高度（Z值）变化的速度，量化地形的陡峭程度。坡向是指坡度最大时的指南针方向。二阶导数包括剖面曲率。剖面曲率是通过分别沿着和横跨最大坡度方向计算出来......

ABSTRACT

Many types of maps can be created by neighborhood operations on a continuous surface such as provided by a digital elevation model. These most commonly include?rst derivatives slope or aspect, and second derivatives planimetric or pro?le curvature. Such variables are often used in geomorphic analyses of terrain. First derivatives also provide subtle enhancements to hill-shaded maps. For example, some maps combine oblique and vertical illumination, with the latter re?ecting variations in slope. This study illustrates how second derivative maps, in conjunction with hill-shading, can cartographically enhance topographic detail. A simple conic model indicates that image-tone edges where slope or aspect varies by less than 0.5° are visible on curvature maps. Hill-shaded images combined with curvature enhance the continuity of naturally occurring tonal edges, especially in strongly illuminated areas. Variations in planimetric and pro?le curvature seem to be especially effective at highlighting convergent and divergent drainages and variations in erosion rate between or within sedimentary units, respectively. Shading curvature with consideration given to illumination models can add detail to hill-shaded terrain maps in amanner similar to cognitive models employed by map viewers.

Keywords: Planimetric curvature  Profile curvature  Illumination  Shaded relief Cartography  Geographic visualization

1. Introduction

Geomorphologists and cartographers both employ variables derived from elevation data to quantify the shape or structure of topographic surfaces (Robinson et al., 1995; Wilson and Gallant, 2000; Slocum et al., 2004; Li et al., 2004). This study focuses on the cartographic representation of variables computed from local (neigh-borhood) operations directly from the topographic data, the“primary attributes”discussed inWilson and Gallant (2000). Also addressed are operations that treat the terrain as a continuous functionf(x,y,z) and compute?rst and second order derivatives.

First order derivatives include slope gradient......