Map vectorization is one of primary ways to capture digital spacial information from topographic map 地形图的矢量化是获取数字地理信息的主要途径之一。
The topographic map contains a large amount of elevation information , and is an important source of dem data 地形图中包含了大量的高程信息,是dem数据的重要的来源。
The problem of how to draw dem data from the existing topographic map becomes the important research subject 如何快速有效地从现有地形图中提取dem数据的问题成为重要研究课题。
Look up countries , cities , and airports and obtain topographic maps , weather data , and selected satellite imagery -提供电子地图产品网上地图下载数据采集地图加工服务航片和卫片解译及mapinfo产品代理。
Quality requirement for digital products of surveying and mapping - part 1 : quality requirement for digital line topographic map , digital elevation model 数字测绘产品质量要求第1部分:数字线划地形图数字高程模型质量要求
All topographic maps except the 1 to 1000 basic map series are bilingual and the latter will be bilingual by 1999 除1 ： 1000比例基本地图系列地图外，所有地图都以中英文说明，而1 ： 1000比例系列地图也将于一九九九年转为有中英文说明。
Our experiments show that the photogrammetry with digital camera has a better precision and the large scale topographic map and orthograph can be produced with it 试验证明利用数码相机进行摄影测量精度很高，能够用来测制大比例尺地形图和正射影像图。
This method is of high efficiency and accuracy , and it is used to discover automatically features change before beijing topographic map database updating on scale of 1 : 500 这种方法效率高，准确性强，已成功用于北京市1 : 500地形图数据库更新前地物变化的自动发现。
Different kinds of battle conformation put forward distinct request to topographic supply of campaign , but accurate topographic maps in various scales is the basic demand 不同的战争形态对作战测绘保障提出不同的要求，提供多种比例尺的精确纸质地形图是军事测绘保障的基本方式。
In topographic maps , contour lines are the most important features to characterize three - dimensional terrain on two - dimensional map sheets , so its vectorization is in urgent 而在地形图中大量的等高线被用于描述三维地形信息,其矢量化工作更为紧迫,并且它也是生成dem数据的一种有效方法。
