共查询到20条相似文献，搜索用时 109 毫秒
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利用微机和基于栅格数据的软件系统,采用主成分分析(PCA)详细分析了浙江省南部飞云江下游地区TM多波段数据的信息特征,从中找出了适合于假彩色合成和土地利用分类的最佳波段组合;利用PCA结果,进一步结合较为新颖二图象增强方法-彩色空间变换(IHS变换),讨论了TM图象PCA变换和IHS变换相互结合的优势,为研究区遥感信息的应用提供了新的技术途径;通过对TM图象信息特征分析和图象增强处理,进行了土地利用自动分类的试验.对研究区的土地利用空间结构进行了分析,并针对一些具有区域特点、专题信息进行了提取和分析,提出了一些可供当地政府决策参考的区域发展建议. 相似文献
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本文分析了西格陵兰Disko湾的表层沉积物硅藻,发现并统计了分属于39个属的78个硅藻种及其变种。应用对应分析方法,对Disko湾表层沉积硅藻组合进行了分类:组合Ⅰ为Fragilariopsis cylindrus-Fragilariopsis oceanica组合,主要分布在西格陵兰Disko湾南部的近岸和外海处;组合Ⅱ为Detonula confervaceae休眠孢子-Thalassiosira nordenskioeldii组合,都分布在Dis-ko湾北部海域。其中,根据海流等环境要素的不同,组合Ⅰ又可进一步划分为两个亚区:组合Ⅰa为F.cylindrus-F.oceanica-Pauliella taeniata组合,主要分布于沿岸海区;组合Ⅰb为F.cy-lindrus-F.oceanica-Thalassiosira antarcticavar.borealis休眠孢子-Thalassiosiracf.antarcticavar.borealis组合,分布于外海区域。 相似文献
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对青海湖地区黑马河、泉湾湿地进行了植被样方调查,并由湖岸向外每间隔100～150 m采集表土与苔藓样品进行花粉分析。结果显示,黑马河、泉湾湿地表土花粉与对应样方植被关系密切,花粉组合能较好地反映样方植被特征,同时,桦木属、蒿属、藜科、白刺属、胡颓子科、麻黄科等花粉类型少量出现,为外来花粉。R值分析表明莎草科花粉相对呈高代表性,毛茛科、委陵菜属、禾本科、菊科、报春花科、玄参科等呈低代表性。该研究为在青海湖及其它地区利用花粉重建古植被提供了重要的参考依据。 相似文献
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岷江上游干旱河谷区阳坡土壤性质空间分异特征 总被引：1，自引：0，他引：1
通过现场调查取样和室内理化试验,定量分析了岷江上游干旱河谷区阳坡土壤性质的空间变异特征,结合已有植被格局进行了区域土壤植被系统综合分析.研究结果表明:岷江上游干旱河谷区阳坡表层土壤粘粒含量极低,>0.25 mm颗粒占45.2%;土壤微团聚体中表层<0.002 mm的部分存在向下淀积或流失现象;pH值偏高,土壤N、P养分处于缺乏状态,且有效养分含量极低,土壤肥力水平低;土壤性质水平分异图显示:坡上部的疏林地土壤肥力高于其他土地利用地块,相对新植林地而言,靠近阴坡的疏林地植被恢复潜力更大. 相似文献
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青藏高原典型区微塑料分布特征及来源分析 总被引：3，自引：0，他引：3
微塑料作为一种环境中普遍存在的新型污染物正在引起越来越多的关注。本文基于2019年5—7月在青藏高原地区采集的53个水样和52个土壤样品微塑料检出结果,分析了研究区水土环境中微塑料赋存情况,并讨论了其潜在来源。研究区域的微塑料样点分别位于两大区域：青藏高原南部地区和祁连山地区。青藏高原南部地区水体中微塑料浓度显著高于祁连山地区,而土壤中微塑料丰度在两个区域差别不显著（p>0.05）。水土样品中微塑料浓度范围分别为0~1916.66个/m3和0~260个/kg,平均值为(438.21±454.94)个/m3和(48.35±36.25)个/kg。水体中的微塑料以透明纤维为主,主要聚合物为聚丙烯;土壤微塑料中最多的是透明薄膜,主要聚合物为聚乙烯。来源分析表明洗衣废水和旅游业带来的生活垃圾可能是水体微塑料的主要来源,而土壤微塑料潜在主要来源是农业塑料覆膜的使用。研究结果揭示了青藏高原水土环境中微塑料的赋存形态和空间分布特征,可为高寒地区微塑料迁移转化机制研究提供数据支撑。 相似文献
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城镇地籍建库中CASS和MapGIS城镇地籍数据转换研究 总被引：1，自引：0，他引：1
索俊锋 《云南地理环境研究》2011,23(4):63-67
为高效建立城镇地籍数据库,经常要将各类数字地形图数据在南方CASS中编辑、处理,而城镇地籍数据库普遍采用GIS平台进行空间矢量化数据管理分析。结合第二次全国土地调查城镇地籍数据库建设工作,首先分析了CASS和MapGIS地籍数据格式的特点;其次介绍了如何选用有利的转换方法来有效地实现两种数据的转换;最后详细阐述了利用Visual Basic 6.0平台将CASS数据无损转换为MapGIS地籍数据的代码实现,为实现两种数据的共享提供一定的技术支持。 相似文献
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浅地层地震剖面探测技术是一种基于声学原理连续走航式探测水下浅部地层结构与构造、沉积物特征及矿物分布的地球物理探测方法,具有连续性好、分辨率高和直观性强的特点。在湖泊沉积尤其是水下沉积研究中,弥补了沉积物钻孔分析"一柱之见"的局限性,能够更加直观准确地揭示湖泊沉积层垂向和横向地层结构、构造及其空间分布。回顾浅地层地震剖面探测技术的发展历程,基于湖泊地震相解释的原理,其在湖泊水位、湖泊古地质活动、湖盆形态演变等研究中已有一定的应用,初显了浅地层地震剖面探测技术在晚更新世以来湖泊沉积研究中的独特优势。近期,与RS和GIS技术结合,实现了湖泊沉积2D和3D可视化。湖泊水浅、植物多、浮泥厚等因素影响反射波与图像质量,浅地层地震剖面探测技术在硬件设备、数据采集时的参数设置及数据后处理软件功能完善等方面,仍有待提高。 相似文献
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Imbricate reflections commonly occur in the glacigenic section of seismic profiles from the Bjørnøya Trough. This was the main drainage pathway for fast‐flowing ice‐streams from the former Barents Sea and Scandinavian ice sheets. Industry three‐dimensional (3D) seismic data from the southern flank of the Bjørnøya Trough are used here to investigate these imbricate reflections. Integration of vertical seismic sections with 3D plan view images and attribute maps reveal that imbricate reflections at the SW Barents Sea Margin are mega‐scale sediment blocks with a glacigenic origin. Imbricate reflections in two regions to the east of the survey appear on plan‐view as well‐developed lineations of U‐shaped crescents; however, following detailed analysis of their location, geometry and relation to sailing direction during data acquisition, we can demonstrate that these are seismic artefacts. These artefacts are related to the straight parts of east–west‐trending plough marks on the sea floor, having a dip direction that is directly related to the sailing direction of the ship during seismic acquisition. By analysing both real glacigenic imbrications and false imbrications or artefacts, we are able to demonstrate the critical distinguishing criterion. 相似文献
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Mike Warner 《Geophysical Journal International》1987,89(1):21-26
Summary. Conventional migration of deep seismic reflection data often produces disappointingly poor results even when the original unmigrated data are of high quality and are relatively noise free. Surprisingly, deep data often subjectively appear to be best migrated at velocities which are up to 50% less than appropriate interval velocities derived from crustal refraction experiments or directly from stacking velocities. The explanation for this behaviour is that near surface features distort and attenuate the seismic wave field and produce apparent discontinuities in deep reflections. Since these discontinuities are spurious they are not associated with the appropriate large diffractions which real discontinuities at depth would produce. During the process of migration reflections are invented in order to cancel out the missing diffractions thereby producing a "smiley" section which appears overmigrated. Since the lateral extent of individual smiles increases with increasing migration velocity, increasing two-way-time, and increasing seismic wavelength, the effect" is almost unnoticeable on conventional shallow seismic data but is overwhelming for deep crustal data. 相似文献
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Wide-angle vibroseis test across the Rhine graben 总被引：1，自引：0，他引：1
B. Damotte K. Fuchs E. Lüschen F. Wenzel R. Schlich G. Toreilles 《Geophysical Journal International》1987,89(1):313-318
Summary. As a joint operation of ECORS and DEKORP, a deep wide-angle seismic experiment using vibrators was carried out in the autumn of 1984. The object was to get information on the deep crust under the Rhine graben without crossing through sedimentary layers. Offsets were in the range of 50 to 89 km. In the first phase, two vibration points were executed in the Vosges mountains. A signal was received in the Black Forest from solely the farthest VP. In the second phase, fourteen VPs were executed in the Black Forest. No stacking or correlation was performed in the field in France. The quality of the results is good only if an equalization is applied before vertical stacking and correlation in the computing centre. 相似文献
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地震灾害预测和应急模拟系统的设计与应用——以永安市城市应急系统为例 总被引：1，自引：0，他引：1
城市防震减灾是地震潜在频发区提高自然灾害防治能力建设的重要方面。本文结合福建省永安市城市防震减灾信息管理系统的建设,探讨设计防震减灾数值模型,分析模型集成的关键技术,构建了地震风险评估、建筑物易损性评价、生命与财产损失估算、救援与救灾管理调度等模型和基于GIS开发的震害预测和应急模拟系统。该系统在福建省永安市的实际应用表明,通过对地震灾害预测结果的分析,可加强城市抗震中的薄弱环节,为灾区政府应急响应和制订对策提供决策支持辅助信息,从而显著提高城市防震减灾的综合能力。 相似文献
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水资源承载能力评价方法研究及应用 总被引：3，自引：0，他引：3
为全面客观评价水资源承载状况,进而为经济社会发展合理布局提供理论支撑,本文在对水资源承载能力评价研究现状进行综述的基础上,考虑水量、水质、水生态3个要素,讨论分析了水资源承载能力内涵,从水资源承载负荷和承载能力2个方面出发,构建了水资源承载能力评价指标体系,采用实物量指标对水资源承载能力各因素分别评价,采用“短板法”全面考虑各要素评价结果,进而得到水资源承载能力综合评价结果。并以河北省为案例进行水资源承载能力评价,最后结合资源承载状况和超载成因,提出了河北省水资源调控措施建议,以验证评价方法的合理性与可行性。 相似文献
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面向地震应急准备的居民地遥感提取及量化分析 总被引：2，自引：1，他引：1
运用灰度共生矩阵、数学形态学等方法提取新疆新源地区高分一号2 m分辨率影像居民地信息,运用目视解译、影像叠加分析、缓冲区分析等方法,进行居民地量化分级,为地震应急准备提供数据支持。结果表明：研究区在地震烈度为Ⅷ度及以下区域,埋压主要集中在单层结构为主的建筑区;当地震烈度高于Ⅷ度且造成多层建筑大面积倒塌时,县城等人口密集区为首要救援区;在地震应急准备时,应对交通条件三等区和交通条件四等区重点关注,增加应急物资储备点,对山区居民地,应考虑道路毁坏情况,转换救援方式,做好应急预案。 相似文献
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Mishra V Singh V 《Population geography : a journal of the Association of Population Geographers of India》1992,14(1-2):1-26
"The effect of agro-climatic factors on female age at marriage [in India] is studied by carrying out areal analysis of the 1981 Census data. The study found a close association between agricultural and climatic conditions in an area and corresponding female age at marriage. In general, women in Himalayan regions and coastal areas have higher age at marriage than most hinterland regions. Rainfall, altitude, forest area, land availability and productivity are observed to be associated with female age at marriage. In addition, female age at marriage in rural areas is found to be more sensitive to the agro-climatic conditions. It is hypothesized that with socio-economic and technological development, the agricultural and climatic factors are losing their grip on female age at marriage in India." 相似文献
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In case of a complex overburden, the seismic data can be greatly improved by applying a full wavefield redatuming procedure. In practice, the application of the redatuming process to 3-D data acquired by conventional acquisition designs is non-trivial. Because of the large amount of data involved in the 3-D redatuming process and because of the sparseness of these data, it is impossible to apply conventional wave equation datuming directly.
We present a data mapping approach to redatuming (DMR), which follows the concept of Kirchhoff data mapping. A simplified background medium where no ray bending occurs is assumed for the medium below the datum in order to map an input data set referenced to the acquisition surface to an output data set referenced to the new datum level. The DMR method can be interpreted as a simplified version of the Kirchhoff summation redatuming (KSR) method, where one of the 2-D integrals over the acquisition coordinates can be solved analytically. Consequently, in this approach fewer traces are involved in the computation of one time sample (a 2-D integral is computed instead of a 4-D integral), which makes it particularly attractive for the application to 3-D data sets.
In this paper the theory underlying data mapping redatuming is discussed and the proposed approach is tested on fully sampled 2-D and 3-D synthetic data from models with both simple and complex velocity distributions in the subsurface.
The tests clearly show that the objective of producing results that are comparable to the conventional KSR has been achieved. The redatumed traces are dynamically and kinematically correct. Furthermore, these results confirm that the dependency of the new approach on the assumed medium below the datum level is, indeed, weak because the assumption of a velocity medium where no ray bending occurs is already sufficient to produce correct results. 相似文献
We present a data mapping approach to redatuming (DMR), which follows the concept of Kirchhoff data mapping. A simplified background medium where no ray bending occurs is assumed for the medium below the datum in order to map an input data set referenced to the acquisition surface to an output data set referenced to the new datum level. The DMR method can be interpreted as a simplified version of the Kirchhoff summation redatuming (KSR) method, where one of the 2-D integrals over the acquisition coordinates can be solved analytically. Consequently, in this approach fewer traces are involved in the computation of one time sample (a 2-D integral is computed instead of a 4-D integral), which makes it particularly attractive for the application to 3-D data sets.
In this paper the theory underlying data mapping redatuming is discussed and the proposed approach is tested on fully sampled 2-D and 3-D synthetic data from models with both simple and complex velocity distributions in the subsurface.
The tests clearly show that the objective of producing results that are comparable to the conventional KSR has been achieved. The redatumed traces are dynamically and kinematically correct. Furthermore, these results confirm that the dependency of the new approach on the assumed medium below the datum level is, indeed, weak because the assumption of a velocity medium where no ray bending occurs is already sufficient to produce correct results. 相似文献
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梁师俊 《地理与地理信息科学》2011,27(6):74-77
针对城市用地抗震适宜性评价的特点,分析了城市用地抗震适宜性的影响因素和评定准则,并采用三标度矩阵,利用层次分析法确定了各影响因子的权重,将城市用地抗震适宜性、评价因子、评定准则相结合建立物元模型,利用可拓理论,通过关联函数给出各评价因子在城市用地抗震适宜性中的量化值,介绍了城市用地抗震适宜性可拓理论的经典域和节域的建立方法,确定了各评价等级的标准,最后划分研究区域的城市用地抗震适宜性分区,在GIS的支持下,根据空间聚类分析,给出了区划图。评价结果能够为城市用地选择提供决策参考。 相似文献