共查询到19条相似文献，搜索用时 220 毫秒
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实现栅格图形和图像数据矢量化提取的游程轮廓追踪法 总被引：9，自引：0，他引：9
提出一种直接利用栅格图形游程编码进行图斑边界多边形矢量化提取的有效方法。对遥感图像专题信息和栅格型地理空间分析结果的矢量化提取是GIS的重要手段 ,栅格数据结构可简化解决叠置分析等一类空间分析问题 ,其中需要高效矢量化技术的支撑。本方法充分利用栅格游程编码所具有的可操作性强、检索和转换便捷、隐含横向差异信息、可处理高精度和大规格图形和图像等特征 ,定义了“上邻游程”和“下邻游程” ,并采用相应有效查找算法和基于游程轮廓追踪的矢量化技术 ,使得计算机处理栅格数据矢量化的规模、精度和效率明显提高 ,可广泛应用于栅格型地理空间分析和遥感图像处理等方面。 相似文献
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《武汉大学学报(信息科学版)》2010,(9)
提出了一种基于游程编码技术和栅格叠置思想的缓冲区生成算法,其基本思路为:用一个宽度等于缓冲距离的"刷子"沿缓冲目标进行跟踪标描,标记穿越栅格并进行动态叠置,得到栅格形式的缓冲区,然后进行结果矢量化。以线状目标集为例进行了测试和分析,结果表明,该算法在时间复杂度、空间复杂度、计算精度等方面具有一定优势,是一个较为实用的缓冲区生成算法。 相似文献
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提出了一种适合于二值栅格地理数据版权保护的数字水印算法。首先,对二值栅格地理数据及其水印特征进行分析;在此基础上,引入游程长度编码思想,对二值栅格地理数据进行游程长度编码;最后,结合人类视觉系统特征,通过修改游程长度奇偶性的方式,将有意义的水印信息嵌入到二值栅格地理数据中。实验结果表明,所提出的算法能较好地保持二值栅格地理数据的视觉特征,有效地解决了目前所存在的二值栅格地理数据水印嵌入难、水印容量低等问题,且对压缩、加噪、裁剪等水印攻击具有较好的鲁棒性。 相似文献
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基于十进制Morton码的线性四叉树动态编码方法研究 总被引：5，自引：0，他引：5
本文提出一种在遍历栅格矩阵的过程中直接生成四叉树的动态编码方法。该方法用栈代替常规线性表,在提取栅格后,直接检测其属笥值,生成Ｍｏｒｔｏｎ码,并同步地对已检测过的栅格进行合并,以动态地建立线性四叉树。本文叙述了这种动态编码方法的思维,并给出了实现该方法的算法,最后根据测试结果比较了动态编码与静态编码的运行效率和内存占用量。 相似文献
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线性要素栅格数据矢量化快速简便算法设计与实现 总被引：1，自引：0，他引：1
基于追踪圆线性要素矢量化算法,总结该方法的特性与不足之处,在此基础上提出改进的追踪框线性要素矢量化算法,并在VS2005环境下采用C＋＋语言实现线性要素矢量化功能。实验证明：该算法具有算法简洁、速度快、内存占用少,容易编程实现等特点,且矢量化效果十分理想。 相似文献
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针对一些通用的空间数据的数据交换格式进行了研究，并就不同数据格式的数据量进行了对比实验。结果表明，在栅格数据中，．bmp格式的数据量最大，.jpg格式和．gif格式的数据量较小；矢量格式的数据量的大小与空间数据的属性有关，在几种常用的矢量格式中，．e00格式的数据量最大。 相似文献
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This article mainly introduces a class of encoding and compression methods for hexagonal raster data. A new encoding mode is established with the introduction of the Gosper curve, which has good spatial aggregation. On this basis, straightforward encoding, lossless coding compression, and lossy coding compression can be carried out. First, the bidirectional correlation between the Gosper curve and the hexagonal grid data is established, and the Gosper coding value of each raster unit is determined. Then, the lossless compression of the data is completed by performing run‐length encoding on the coding set. Following the Gosper curve trend, partial grid units are semantically changed via adjacent fusion under certain threshold constraints. The run‐length encoding is carried out again to complete the lossy compression and further reduce the amount of encoding required. A break‐detection step is added during the process to avoid regional breaks. The experimental results show that the proposed method can efficiently compress data. Additionally, data compression of multi‐resolution and varying fusion thresholds is explored to summarize general patterns. Finally, the method proposed is compared with traditional row‐coding compression in hexagonal and quadrilateral grids to highlight its advantages for hexagonal raster data. 相似文献
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基于二叉树的栅格数据快速编码及其实现 总被引：2，自引：0，他引：2
在对常规编码方法存在的不足进行分析的基础上，提出了在一次遍历栅格数据过程中生成线性二叉树的快速动态编码以及地程编码方法，该方法用堆栈的思想代替传统的线性表，以十进制orton码为顺序提取栅格单元数据并介入栈，以压栈的方式完成栅格单元或结点向上层的递归合并。当对整个栅格数据遍历一次后，栈中剩下的记录便是所需的线性二叉树编码结果。通过对算法的分析表明，该方法具有明显的优点和重要意义。 相似文献
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S. S. Ray Anil Sood Gargi Das Sushma Panigrahy P. K. Sharma J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2005,33(2):181-188
In this study, an attempt has been made to suggest crop diversification based on soil and weather requirements of different
crops. State level spatial databases of various agro-physical parameters such as rainfall, soil texture, physiography and
problem soil along with the agricultural area derived from remote sensing data were integrated using GIS. A raster based modelling
approach was followed to arrive at suitable zones for practicing different cropping systems. The results showed that the south-western
Punjab is suitable for low water requiring crops such as desi cotton, pearl millet, gram etc., where as north-eastern Punjab
with high rainfall and excess drainage should practice maize based cropping system. Rice can be substituted by maize and other
crops in Central Punjab, where water table is going down fast. Using this approach the area of rice based cropping system
can be reduced from present 24.7 lakh ha to 19.6 lakh ha, thereby reducing the degradation of valuable land and water resources. 相似文献
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将静态的纸张和影像地图及传统的各类地理信息转化为数字时代的电子信息,其中的关键环节是怎样将栅格数据矢量化。通过在国产软件SuperMap环境下进行栅格数据矢量化过程,详细描述了栅格数据、矢量数据、坐标系、投影坐标系、地图配准和镶嵌等专业基础知识在实际中的应用。 相似文献
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Modelling forest canopy gaps using LiDAR-derived variables 总被引：1，自引：0，他引：1
Remote sensing has revolutionized forest management and has been widely employed to model canopy gaps. In this study, a canopy height model (CHM) and an intensity raster (IR) derived from light detection and ranging (LiDAR) data were used to model canopy gaps within a four-year-old Eucalyptus grandis forest using an object-based image analysis (OBIA) approach. Model thematic accuracies using the CHM, intensity raster and combined data set (CHM and IR) were all above 90%, with KHAT values ranging from 0.88 to 0.96. Independent test thematic accuracies were also above 90%, with KHAT values ranging from 0.82 to 0.91. A comparative area-based assessment yielded accuracies ranging from 70 to 90%, with the highest accuracies achieved using the combined data set. The results of this study show that using a CHM and intensity raster, and an OBIA approach, provides a viable framework to accurately detect and delineate canopy gaps within a commercial forest environment. 相似文献