共查询到19条相似文献，搜索用时 171 毫秒
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介绍了以ArcGIS为数据处理平台,利用VBA语言进行的二次开发,用来实现不同类型数据的自动裁切。可以进行批量生产,具有快捷、简单、实用的特点。 相似文献
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ArcGIS系列软件提供了多种形式的地理处理工具,模型构建器和Python脚本是其中的典型代表。本文以地形图数据库批量图幅裁切问题为例,按照数据准备、单图框裁切、重复单图框裁切的思路将这一地理处理过程分解,用模型构建器和Python脚本两种工具分别实现了矢量数据批量裁切的功能,详细地介绍了两种方法的技术要点及细节,获得了预期的结果数据,并比较分析了两者的优劣势及相互联系。 相似文献
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影像地图编制中图幅的自动拼接与裁切——以《苏州市影像地图集》的编制为例 总被引：1，自引：0，他引：1
影像图幅的拼接与裁切是影像地图编制中的一个重要环节,其目的是获得一幅完整的表示某一制图范围的基础影像底图。本文首先分析了传统方法的不足,然后提出了一种简单的自动拼接与裁切方法,该方法能方便地处理任意多幅源影像的拼接与裁切问题,有效地提高拼接与裁切的效率与质量。 相似文献
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在地图瓦片数据库制作中,通常使用标准地形图图幅对影像数据切片,在相邻图幅接边处,由于数据不完整瓦片的相互压盖,造成显示地图时出现空白区域,使用改进的非标准图幅作为数据裁切框,可有效解决该问题。本文阐述了改进的数据裁切框生成的原理和流程,并基于GDAL/OGR开源库,在Visual Studio中编程实现。 相似文献
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无齿孔潜影胶片的裁切是摄影胶片冲洗处理的第一道工序,本文简要介绍了潜影胶片精密裁切控制的相关技术,提出了关键技术解决途径,设计并研制了精密裁切控制系统,已在裁切机研制中得到了应用。 相似文献
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利用等高线数据自动生成地性结构线的算法研究 总被引：4，自引：0，他引：4
地性线数据是关于DEM精确建模、制图综合的重要地理信息数据。在对基于等高线数据自动追踪地性线算法进行分析比较的基础上，提出一种简单实用的地性线自动追踪算法，并给出实验结果。 相似文献
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The purpose of this paper is to suggest estimators for the parameters of spatial models containing a spatially lagged dependent
variable, as well as spatially lagged independent variables, and an incomplete data set. The specifications allow for nonstationarity,
and the disturbance process of the model is specified non-parametrically. We consider various scenarios concerning the pattern
of missing data points. One estimator we suggest is based on a smaller but complete subset of the sample; another is based
on a larger but incomplete subset of the sample. We give large sample results for both of these cases. 相似文献
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Optimum data weighting and error calibration for estimation of gravitational parameters 总被引：1，自引：0，他引：1
Francis J. Lerch 《Journal of Geodesy》1991,65(1):44-52
Summary A new approach has been developed for determining consistent satellite-tracking data weights in solutions for the satellite-only gravitational models. The method employs subset least-squares solutions of the satellite data contained within the complete solution and requires that the differences of the parameters of subset solutions and the complete solution to be in agreement with their error estimates by adjusting the data weights. GEM-T2 model was recently computed and adjusted through a direct application of this method. The estimated data weights are markedly smaller than the weights implied by the formal uncertainties of the measurements. Orbital arc tests as well as surface gravity comparisons show significant improvements for solutions when more realistic data weighting is achieved. 相似文献
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基于小波与遗传算法的特征提取与特征选择 总被引：5，自引：0，他引：5
高维遥感数据的分类与识别与传统的多光谱遥感分类技术具有明显的区别。本文提出了一种基于遗传算法和小波／小波包分析相结合的特征提取方法用于高维遥感数据降维与分类。该方法综合了遗传算法的全局优化和小波／小波包分析的多尺度、多分辨率的特点。首先,通过离散的小波变换(DWT)或小波包变换(WP)将高光谱信号变换到特征域进行光谱分解。由于DWT变换是一种线性变换,不同尺度的DWT系数可作为线性光谱特征。然后,对这些线性光谱特征利用遗传算法结合训练样本计算类内／类间距离搜索最优分类子集,其具体染色体编码取可能的特征号,适应度函数基于样本平均Jeffries-Matusita距离计算。所用的分类器采用最大似然分类器。试验结果表明该方法与常规特征提取算法如主成分变换(PCA)、判别分析特征提取(DAFE)、决策边界特征提取(DBFE)相比,能提高分类精度约1.1％-6.5％。 相似文献
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传统道路地图构建方法将轨迹点（线）同等对待提取道路数据,忽略车辆轨迹的空间差异性,制约其结果精度与应用范围。为此,本文根据轨迹速度将轨迹线集分割滤选为3个轨迹线子集,将轨迹方向与Delaunay三角网模型集成探测路网拓扑结构;顾及轨迹线子集的特征差异选取不同参数值和约束条件并分层提取道路几何、交通语义数据,分别构建3个道路图层;运用缓冲区方法并根据道路几何、语义特征将多个道路图层融合为单个完整道路地图。运用出租车轨迹数据进行试验分析,结果表明：该方法顾及轨迹分布差异性,能将道路几何、交通语义信息融合提取,更适于处理复杂道路结构下的轨迹线。 相似文献
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《地理信息系统科学与遥感》2013,50(4):411-423
Support vectors, which usually compose a subset of training sets, determine the decision function of support vector machine (SVM) classification. Selecting a subset including the support vectors through reducing a large training set is a challenge. This paper examines how different linkage techniques in a clustering-based reduction method affect classification accuracy for semiarid vegetation mapping. The investigated linkage techniques include single, complete, weighted pairgroup average, and unweighted pair-group average. Using a multiple-angle remote sensing data set, there is no loss of SVM accuracy when the original training set is reduced to 21%, 14%, 20%, and 20% for these four linkage techniques, respectively. 相似文献
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High-data dimensionality is a common problem in hyperspectral data processing. Consequently, remote sensing techniques that reduce the number of bands are considered essential tools for most hyperspectral applications. The aim of this study was to examine the utility of the random forest ensemble to select the optimal subset of hyperspectral bands to predict the age of Pinus patula stands. Airborne AISA Eagle hyperspectral image data were collected over the study area. The random forest ensemble was used to test whether the forward or backward variable selection methods could identify the optimal subset of bands. Results indicate that both the selection methods produced high-predictive accuracies (root mean square error = 3.097 years). However, the backward variable selection method utilized 206 bands for the final model, while the forward variable selection utilized only a small subset of non-redundant bands (n = 9) while preserving the highest model accuracy (R 2 = 0.6). 相似文献
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《制图学和地理信息科学》2013,40(5):300-302
The Spatial Data Transfer Standard (SDTS) was designed to transfer both vector and raster data sets. In the early development of the SDTS, the designers recognized that there was a need to transfer raster data in addition to the more challenging vector data. As a result, the SDTS includes a “raster module” that accommodates a variety of raster data structures and formats. A raster profile is being developed that will exercise a selected subset of SDTS capabilities in order to provide a simple-to-use transfer of complete raster data sets. 相似文献
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ABSTRACTDot maps have become a popular way to visualize discrete geographic data. Yet, beyond showing how the data are spatially distributed, dot maps are often visually cluttered in terms of consistency, overlap, and representativeness. Existing clutter reduction techniques like jittering, refinement, distortion, and aggregation also address this issue, but do so by arbitrarily displacing dots from their exact location, removing dots from the map, changing the spatial reference of the map, or reducing its level of detail, respectively. We present BinSq, a novel visualization technique to compare variations in dot density patterns without visual clutter. Based on a careful synthesis of existing clutter reduction techniques, BinSq reduces the wide variety of dot density variations on the map to a representative subset of density intervals that are more distinguishable. The subset is derived from a nested binning operation that introduces order and regularity to the map. Thereafter, a dot prioritization operation improves the representativeness of the map by equalizing visible data values to correspond with the actual data. In this paper, we describe the algorithmic implementation of BinSq, explore its parametric design space, and discuss its capabilities in comparison to six existing clutter reduction techniques for dot maps. 相似文献