共查询到18条相似文献，搜索用时 234 毫秒
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面向对象的退耕还林造林效果遥感特征提取技术研究 总被引：3，自引：0，他引：3
以河北省张家口市2002年的退耕还林地为研究对象,以高空间分辨率(以下简称高分辨率)遥感(Quick-bird-快鸟,分辨率0.6m)为信息载体。运用严格的传感器物理模型对快鸟预正射影像进行正射处理,采用Median滤波、Gaussian滤波和均值滤波三种滤波技术对图像进行增强处理。采用面向对象的图像信息提取技术,提取退耕还林地树冠特征值,进而计算退耕还林造林保存率。研究结果表明:由遥感数据自动提取的树冠尺寸(直径)在1.2m以上,平均保存率为85.11%,精度达到了89.837%。 相似文献
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以山西省古交市嘉乐泉乡为试验区,采用SPOT-5的10m、5m和2.5m 3种影像数据对退耕还林地面积进行分类监测。所设计的2种方案分别是:1)将地物类型分为7类,退耕还林地作为一种单独地类,对3种影像数据进行计算机自动分类和2.5m影像的人工解译分类;2)借助退耕还林作业设计图,将退耕还林地块影像分割出来,对退耕还林地和未退耕还林地进行有监分类。精度验证表明,第一种方案中2.5m融合图像的人工解译分类,退耕还林地的分类精度在50%以下;第二种方案中3种影像数据的总体分类精度均大于90%。建议在退耕还林地的作业设计图电子化的基础上,应用SPOT-5数据监测退耕还林地的任务完成和植被覆盖情况。 相似文献
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基于高分光学遥感影像技术,对湖南省油茶产业大县汉寿县油茶林地进行分类特征提取、标注样本类别及建立分类模型等操作,实现研究区油茶林地高精度识别。结果显示：利用基于高分光学遥感影像的深度网络智能化提取油茶林地及人工确认的数据分析方法能够很好识别汉寿县油茶林地的空间分布,与2022年全县油茶精细化调查面积数据对比后精度较高(优于70%);空间分布上,汉寿县太子庙镇的油茶分布集中且面积最大,和地面调查的面积数据相比,该镇的油茶分布面积提取精度最高,为92.57%。研究方法能够较为精准地识别汉寿县油茶林地斑块,从而为湖南省油茶林地遥感普查与保护规划提供重要参考。 相似文献
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典型退耕还林区景观格局变化特征 总被引：1，自引：0，他引：1
以1990、2001、2006年3个时期的Landsat TM遥感影像和1999年的森林资源分布图为数据源,运用景观格局分析方法,结合遥感与地理信息系统技术,对典型退耕区沐川县土地利用与覆盖变化进行分析,结果表明:退耕区耕地面积随时间的变化成逐年下降趋势,林地面积中变化最大的是竹林,且变化时期主要在1999—2001年。1999—2001年间,在西南部高丘河谷平坝区,斑块的多样性增大,破碎度增加;在海拔较高的区域,破碎度变小。人为干扰是土地利用变化驱动力的重要因素,由于退耕还林工程实施及地方政策的引导,低海拔地区土地利用变化明显。 相似文献
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利用QuickBird高分辨率影像,根据QuickBird影像自身特点,改进已有像元二分模型2个参数的估算方法,建立用NDVI归一化植被指数定量估算植被覆盖度的模型,并将该模型应用到退耕地中.结果表明:利用QuickBird影像监测退耕地的植被覆盖度受到退耕苗木树冠大小的限制,树龄小于1年的树木监测效果不佳;树龄大于2.5年的树木监测效果较好,精度可达83%以上,表明用此改进模型对2.5年以上退耕地进行植被覆盖度监测是可行的. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):482-499
This article reviews the research and application of airborne laser scanning for forest inventory in Finland, Norway and Sweden. The first experiments with scanning lasers for forest inventory were conducted in 1991 using the FLASH system, a full-waveform experimental laser developed by the Swedish Defence Research Institute. In Finland at the same time, the HUTSCAT profiling radar provided experiences that inspired the following laser scanning research. Since 1995, data from commercially operated time-of-flight scanning lasers (e.g. TopEye, Optech ALTM and TopoSys) have been used. Especially in Norway, the main objective has been to develop methods that are directly suited for practical forest inventory at the stand level. Mean tree height, stand volume and basal area have been the most important forest mensurational parameters of interest. Laser data have been related to field training plot measurements using regression techniques, and these relationships have been used to predict corresponding properties in all forest stands in an area. Experiences from Finland, Norway and Sweden show that retrieval of stem volume and mean tree height on a stand level from laser scanner data performs as well as, or better than, photogrammetric methods, and better than other remote sensing methods. Laser scanning is, therefore, now beginning to be used operationally in large-area forest inventories. In Finland and Sweden, research has also been done into the identification of single trees and estimation of single-tree properties, such as tree position, tree height, crown width, stem diameter and tree species. In coniferous stands, up to 90% of the trees represented by stem volume have been correctly identified from canopy height models, and the tree height has been estimated with a root mean square error of around 0.6 m. It is significantly more difficult to identify suppressed trees than dominant trees. Spruce and pine have been discriminated on a single-tree level with 95% accuracy. The application of densely sampled laser scanner data to change detection, such as growth and cutting, has also been demonstrated. 相似文献
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花椒不同造林密度成效试验研究 总被引：1，自引：0，他引：1
在天水地区温暖半湿润半干旱气候条件下,对花椒不同造林密度成效进行对比试验研究。结果表明:造林密度对花椒成活率影响不明显,但对生长量和结果量影响显著。营造花椒经济林,采取3 m×4 m、3 m×3 m株行距,花椒树生长快、树形成型早,定植后第3年开始结果,第6年实现丰产,平均产花椒果皮1 350kg/hm2以上;营造花椒生态经济兼用林,株行距采取2 m×4 m、2 m×3 m,第4年按隔株挖除的方法调整栽培密度,能增加枝量,扩大树冠,第6年花椒果皮产量可达到1 200 kg/hm2。 相似文献
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Yasumasa Hirata Ryuichi Tabuchi Pipat Patanaponpaiboon Sasitorn Poungparn Reiji Yoneda Yoshimi Fujioka 《Journal of Forest Research》2014,19(1):34-41
Mangroves play important roles in providing a range of ecosystem services, mitigation of strong waves, protection of coastlines against erosion, maintenance of water quality, and carbon sink in the context of global warming. For trees in mangrove forests in southern Ranong Province, Thailand, we investigated the allometric relationship between crown area derived from high-resolution satellite data and stem diameter and used the resulting model to estimate aboveground biomass. We used QuickBird panchromatic and multispectral data acquired for the study area on 15 October 2006 as the high-resolution satellite data. Individual tree crowns were extracted from the satellite image of panchromatic data by using the watershed method, and the species were identified by using the maximum-likelihood method for the multispectral data. Overall classification accuracy for species identification was 88.5 %. The biomass derived from our field survey was plotted against aboveground biomass in the sample plots, estimated from the QuickBird data. The regression line through the origin between the satellite-estimated biomass and biomass based on the field data had a slope of 1.26 (R 2 = 0.65). Stand aboveground biomass estimated from the high-resolution satellite data was underestimated because of a lack of data on the biomass of suppressed trees and inappropriate segmentation of crowns of large trees into two or more trees. 相似文献
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【目的】探索无性系、株行距及两者交互作用对杨树人工林的林木生长和树冠结构的影响。【方法】采用双因素随机试验设计,通过调查36块13年生杨树样地胸径、树高、活枝下高和冠幅等指标,以综合指数法构建3个林分综合指数(生长指数、冠形指数、干冠协调指数)。【结果】南林95杨和南林895杨的胸径、树高和生长指数显著高于南林797杨(P <0.05)。南林797杨的冠幅、树冠体积和树冠圆满度显著高于南林895杨,与南林95杨差异不显著(P> 0.05)。株行距为6 m×6 m和4.5 m×8 m的林分胸径、冠形指数和生长指数均显著高于5 m×5 m和3 m×8 m林分,不同密度林分对树高影响不显著(P> 0.05)。在相同密度条件下,正方形和长方形配置对东西和南北冠幅有显著影响,较大株行距促进树冠生长,但对胸径、树高和平均冠幅等影响不显著(P> 0.05)。无性系和株行距对冠长、活冠比、树冠表面积和干冠协调指数影响均不显著,且无性系和株行距对林木生长和树冠结构均无显著交互作用(P> 0.05)。【结论】杨树无性系对林木胸径、树高和树冠结构的影响大于株行距。综合考虑林木生长和树冠结构等两个方面,在类似的立地条件上,相比于其它无性系和配置方式,以南林95杨在种植株行距为6 m×6 m(278株/hm^2)时具有培育大胸径林木的潜力,适于培育速生、优质大径材。 相似文献