面向服务的信息化测绘关键问题探讨   总被引：1，自引：1，他引：0  

冯学兵  顾学明  范文革 《北京测绘》2008,(3):1-4

首先对信息化测绘的内涵进行了分析,提出了信息化测绘的服务本质,加强地理信息资源建设的关键任务,提出以数据库作为地理信息载体的观点;提出了信息化测绘建设的技术思路,总结了地理数据库的逻辑结构;对信息化测绘的组织运行方式提出了建议.  相似文献   

Mapping of riparian invasive species with supervised classification of Unmanned Aerial System (UAS) imagery     

《International Journal of Applied Earth Observation and Geoinformation》2016

Riparian zones are key landscape features, representing the interface between terrestrial and aquatic ecosystems. Although they have been influenced by human activities for centuries, their degradation has increased during the 20th century. Concomitant with (or as consequences of) these disturbances, the invasion of exotic species has increased throughout the world’s riparian zones.In our study, we propose a easily reproducible methodological framework to map three riparian invasive taxa using Unmanned Aerial Systems (UAS) imagery: Impatiens glandulifera Royle, Heracleum mantegazzianum Sommier and Levier, and Japanese knotweed (Fallopia sachalinensis (F. Schmidt Petrop.), Fallopia japonica (Houtt.) and hybrids). Based on visible and near-infrared UAS orthophoto, we derived simple spectral and texture image metrics computed at various scales of image segmentation (10, 30, 45, 60 using eCognition software). Supervised classification based on the random forests algorithm was used to identify the most relevant variable (or combination of variables) derived from UAS imagery for mapping riparian invasive plant species. The models were built using 20% of the dataset, the rest of the dataset being used as a test set (80%).Except for H. mantegazzianum, the best results in terms of global accuracy were achieved with the finest scale of analysis (segmentation scale parameter = 10). The best values of overall accuracies reached 72%, 68%, and 97% for I. glandulifera, Japanese knotweed, and H. mantegazzianum respectively. In terms of selected metrics, simple spectral metrics (layer mean/camera brightness) were the most used. Our results also confirm the added value of texture metrics (GLCM derivatives) for mapping riparian invasive species.The results obtained for I. glandulifera and Japanese knotweed do not reach sufficient accuracies for operational applications. However, the results achieved for H. mantegazzianum are encouraging. The high accuracies values combined to relatively light model-inputs needed (delineation of a few umbels) make our approach a serious contender as a cost-effective tool to improve the field management of H. mantegazzianum.  相似文献   

四川天宝山铅锌矿床硫化物微量元素组成:LA-ICPMS研究   总被引：20，自引：11，他引：9  

叶霖  李珍立  胡宇思  黄智龙  周家喜  樊海峰  DANYUSHEVSKIY Leonid 《岩石学报》2016,32(11):3377-3393

"川滇黔接壤铅锌矿集区"是我国西南大面积低温成矿域的重要组成部分,对于其中铅锌矿床是否属于MVT型矿床存在较大争议。本文以该矿集区中代表性矿床——四川天宝山矿床为例,通过LA-ICPMS原位元素分析,结合元素Mapping,以认识该矿床中闪锌矿和方铅矿微量元素组成特征及其赋存状态。研究表明,矿床中闪锌矿以富集Cd、Ge贫Fe、Mn、In、Sn、Co为特征,这些元素均以类质同象形式赋存于闪锌矿中,但含量变化范围较大,这可能与其成矿流体属于低温混合流体有关,这类盆地卤水流体在长期和长距离运移过程中,流经不同基底地层,活化出其中不同微量元素,因此成分变化较大,但以低温元素为主。此外,矿床中闪锌矿Ge和Cu呈现较好正相关关系,暗示其与Zn置换方式为:nC u~(2+)+Ge~(2+)(n+1)Zn~(2+),这可能是该矿床富集Ge的重要原因之一;矿床中方铅矿以富集Ag、Sb贫Bi为特征,含微量Cd和Tl,类质同象是这些元素主要赋存形式,其置换方式为(Ag)~(1+)+(Sb)~(3+)2Pb~(2+);矿床中Ge主要赋存于闪锌矿中,而方铅矿中不含Ge。总体上,本矿床硫化物微量元素组成与MVT型矿床基本一致,明显有别于喷流沉积型矿床、岩浆热液型矿床和远源夕卡岩型矿床,其成矿温度属于低温范围,成矿流体运移方向可能为深部→浅部。结合其矿床地质地球化学特征,本文认为天宝山铅锌矿床属于MVT型矿床,但其中闪锌矿中富集Cu,而方铅矿中富集Ag,可能暗示其形成具有一定特殊性。  相似文献   

Mapping optimization based on sampling size in earth related and environmental phenomena   总被引：1，自引：1，他引：0  

K. Modis  G. Papantonopoulos  K. Komnitsas  K. Papaodysseus 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(1):83-93

A critical sampling grid can be defined for an earth related natural variable distributed in space, according to established theoretical results and under certain mathematical conditions. Sampling above this critical limit does not substantially improve mapping results, while based on this limit the ideal process of reproducing the original phenomenon is theoretically defined. The aim of the present paper is, by using an innovative approach; to investigate the validity of commonly used interpolation algorithms, both stochastic and deterministic, below and above this critical sampling limit. When sampling is dense, application to a simulated spatial random field shows that the results are equally accurate with those derived with more sophisticated stochastic methods. On the other hand, when the sampling grid is sparse, deterministic methods produce less accurate results, therefore stochastic algorithms with minimum estimation error are a much better option. To further demonstrate these points, the interpolation algorithms were applied in three different sampling grid densities in a contaminated waste disposal site in Russia.  相似文献   

湖南土壤生态系统对酸沉降的相对敏感性区划     

彭世良  吴甫成 《热带地理》2004,24(1):10-13

以成土母质、土壤酸碱度、土壤类型、植被类型和湿度类型等5个生境因子为基础,建立湖南土壤生态系统对酸沉降的相对敏感性评价指标体系;利用地理信息系统(GIS)工具进行湖南土壤生态系统对酸沉降的相对敏感性区划,结果表明,湖南省可以划分为极敏感区、敏感区、中等敏感区、不敏感区和极不敏感区等5个酸相对敏感性分区,分别占湖南省总面积的2.15%、30.02%、55.01%、10.56%和2.26%.  相似文献   

东天山卡瓦布拉克前寒武纪地块填图方法思考——以大黑山幅1:25万区调为例     

吴玉门  郭华春  吴羿辰 《新疆地质》2012,(Z1):6-9

东天山卡瓦布拉克地区前寒武纪地块为古克拉通构造区,物质构成非常复杂。以大陆层圈构造为理论基础,运用形变地层学和变质构造解析方法为主的岩石地层调查方法,在东天山大黑山地区的1:25万区调中重新选择技术路线和工作方法,提高了区内中深变质岩系研究程度及构造-岩石地层单位划分和填图精度。  相似文献   

基于科学知识图谱的水文化变迁研究方法探析简     

Xiong Yonglan  Zhang Zhiqiang  Wei Yongping  Liu Zhihui  Cheng Guodong 《地球科学进展》2014,29(1):92-103

Cultural transformation (including knowledge innovation, ideological emancipation and slogan publicity, etc.) is one of the most important drivers of changes in water management policies. Earlier studies into water culture were mainly based on qualitative methods. However, using only qualitative methods, it is difficult to reveal the stage characteristics of water culture evolution objectively and accurately. Mapping knowledge domains, a rising knowledge discovery method, can holistically reveal the sources of knowledge and the laws of its development. This paper is devoted to exploiting its potential as a quantitative method for researches targeting at water culture evolution. By extracting the key words related to water from People’s Daily, knowledge domains on water culture evolution in China during 1946 2012 are mapped and interpreted, based on which the water culture evolution is unveiled. By comparing the water culture evolution with changes in water policies, stages of water resource development and extreme hydrological events, it is found that there exist clear relationships. This convinces us that mapping knowledge domains could play an effective role in quantitative research on water culture evolution. Further steps towards better quantitative researches on water culture evolution using this method include the enhancement of the universality of newspapers, improvement on the accuracy of key words extraction, and increase in the precision of visualization analysis.  相似文献   

FY-4A白天对流风暴和闪电产品在华北强雷暴天气分析中的应用          下载免费PDF全文

任素玲  赵玮  曹冬杰  刘瑞霞 《山东气象》2020,40(1):33-46

我国第二代静止气象卫星FY-4A观测能力较之前有明显提升,在天气特别是对流性天气监测和预测中具有较强的应用潜力。利用FY-4A气象卫星多通道扫描辐射成像仪(Advanced Geosynchronous Radiation Imager,AGRI)和闪电成像仪(Lightning Mapping Imager,LMI)数据开展研究,分析了反演产品在强雷暴天气中的应用。研究表明,扫描辐射成像仪多通道组合白天对流风暴红-绿-蓝（red-green-blue,RGB）合成产品可以突出具有强上升气流的对流性雷暴云,较单通道及多通道可见光合成产品具有监测优势;闪电成像仪产品较地面闪电探测闪电产品能够探测到更多的闪电,对新生对流和较弱对流产生的闪电监测具有优势;在华北和黄淮一次强雷暴天气过程中,白天对流风暴RGB合成产品能够监测云系发展的过程,卫星监测闪电活动频数和冰雹活动一致性较好。  相似文献   

三维可视化填图在晴隆锑矿外围勘查中的应用     

李伟 《云南地质》2011,30(4):454-459

三维可视化技术在辅助传统地质方法工作的同时,将复杂地质体形态、地质构造情况以三维的形式表现出来,呈现较丰富的的视觉效果。首次把三维可视化技术应用于贵州晴隆锑矿田找矿,有较好效果。  相似文献   

Glacier fluctuations between 1975 and 2008 in the Greater Himalaya Range of Zanskar, southern Ladakh     

Ulrich KAMP  Martin BYRNE  Tobias BOLCH 《山地科学学报》2011,8(3):374-389

Glaciers in the Himalaya are often heavily covered with supraglacial debris,making them difficult to study with remotely-sensed imagery alone.Various methods such as band ratios can be used effectively to map clean-ice glaciers;however,a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain.Previously,a morphometric mapping approach employing an ASTER-derived digital elevation model has been used to map glaciers in the Khumbu Himal and the Tien Shan.This study on glaciers in the Greater Himalaya Range in Zanskar,southern Ladakh,aims (i) to use the morphometric approach to map large debris-covered glaciers;and (ii) to use Landsat and ASTER data and GPS and field measurements to document glacier change over the past four decades.Field work was carried out in the summers of 2008.For clean ice,band ratios from the ASTER dataset were used to distinguish glacial features.For debris-covered glaciers,topographic features such as slope were combined with thermal imagery and supervised classifiers to map glacial margins.The method is promising for large glaciers,although problems occurred in the distal and lateral parts and in the fore field of the glaciers.A multi-temporal analysis of glaciers in Zanskar showed that in general they have receded since at least the mid-to late-1970s.However,some few glaciers that advanced or oscillated - probably because of specific local environmental conditions - do exist.  相似文献