scholarly journals Application of Geospatial Technology for Wetlands’ Mapping and Change-Detection: A Case Study in Selected Areas of South Eastern Coast in Ampara District, Sri Lanka

2018 ◽  
Vol 1 ◽  
pp. 25-32
Author(s):  
Ibra Lebbe Mohamed Zahir ◽  
Kafoor Nijamir

In global context, the anthropogenic pressure increases the loss of wetland and its resources. Wetlands and estuaries are highly productive and act as critical habitats for a variety of plants, fish, shellfish, and other wildlife (Klemas, 2011). The detection and evaluation of the wetland with modern technology is an important phenomenon to conserve the wetland area and its ecosystem. Remote sensing (RS) has a long history of successful applications within the field of wetland delineation, using a multitude of satellite platforms and sensors (Allan, 2016). This paper is an attempt to object-based approach to derive the change detection inventory information of wetland for selected administrative areas of South Eastern coast in Ampara District within the period of 1991 to 2017 using Toposheets and Google Earth imagery. Further, it also explores the human activities which pressure on wetland including agricultural practices (land encroachment), new settlements, solid waste dumping, land cover changes and etc. Google Earth imagery of 1991 and 2017 were collected and subjected to the GIS analysis to find the result of this study. According to the results, agricultural and built-up area has increased in 1991 by (9.4 per cent), 2017 (16.4 per cent) and 1991 (0.1 per cent), 2017 (2.1 per cent) respectively whereas there has been a decrease in the forest and wetland areas in the years of 1991 (80.3 per cent), 2017 (72.7 per cent) and 1991 (3.5 per cent), 2017 (2.9 per cent) respectively.

1954 ◽  
Vol 2 (2) ◽  
pp. 205 ◽  
Author(s):  
TO Browning

Gryllulus commodus has one generation each year, the active stages being present in summer and autumn and the eggs in winter and spring. Crickets are found in abundance only in areas where the soil is heavy black clay. This affords shelter from desiccation to the eggs, which lose water very rapidly if exposed to dry conditions. Also in these areas there may be an abundance of food for the nymphs and adults, in the form of sown permanent pasture. Where either shelter for the eggs or food for the active stages is lacking the numbers of crickets tend to be lower. Certain aspects of the behaviour and physiology of G. commodus which are important in relation to the survival and multiplication of the species are discussed. The relative chanses in the abundance of crickets in the south-eastern districts of South Australia were determined by a survey method during the period 1949-52. Evidence is presented that differences In the abundance of crickets from year to year are mainly attributable to differences in the amount and distribution of rainfall during the winter and spring, which result in differential survival of the eggs. The history of cricket outbreaks in South Australia is traced and it is concluded that, if present trends in agricultural practices continue, future outbreaks will tend to be more severe and more widespread, although probably not more frequent.


The study examines land use land cover and change detection in Chikodi taluk, Belagavi district, Karnataka. Land use land cover plays an important role in the study of global change. Due to fast urbanization there is variation in natural resources such as water body, agriculture, wasteland land etc. These environment problems are related to land use land cover changes. And for the sustainable development it is mandatory to know the interaction of human activities with the environment and to monitor the change detection. In present study for image classification Object Based Image Analysis (OBIA) method was adapted using multi-resolution segmentation for the year 1992, 1999 and 2019 imagery and classified into four different classes such as agriculture, built-up, wasteland and water-body. Random points (200) were generated in ArcGIS environment and converted points into KML layer in order to open in Google Earth. For the accuracy assessment confusion matrix was generated and result shows that overall accuracy of land use land cover for 2019 is 83% and Kappa coefficient is 0.74 which is acceptable. These outcomes of the result can provide critical input to decision making environmental management and planning the future.


Author(s):  
А.П. ЛАКТИОНОВ ◽  
Е.В. МАВРОДИЕВ

The history of the putative endemic of the Lower Volga valley (the South-Eastern European Russia) Rorippa wolgensis Fursajev ex Laktionov et Mavrodiev nom. nov. is briefly discussed.


2021 ◽  
Vol 13 (12) ◽  
pp. 2299
Author(s):  
Andrea Tassi ◽  
Daniela Gigante ◽  
Giuseppe Modica ◽  
Luciano Di Martino ◽  
Marco Vizzari

With the general objective of producing a 2018–2020 Land Use/Land Cover (LULC) map of the Maiella National Park (central Italy), useful for a future long-term LULC change analysis, this research aimed to develop a Landsat 8 (L8) data composition and classification process using Google Earth Engine (GEE). In this process, we compared two pixel-based (PB) and two object-based (OB) approaches, assessing the advantages of integrating the textural information in the PB approach. Moreover, we tested the possibility of using the L8 panchromatic band to improve the segmentation step and the object’s textural analysis of the OB approach and produce a 15-m resolution LULC map. After selecting the best time window of the year to compose the base data cube, we applied a cloud-filtering and a topography-correction process on the 32 available L8 surface reflectance images. On this basis, we calculated five spectral indices, some of them on an interannual basis, to account for vegetation seasonality. We added an elevation, an aspect, a slope layer, and the 2018 CORINE Land Cover classification layer to improve the available information. We applied the Gray-Level Co-Occurrence Matrix (GLCM) algorithm to calculate the image’s textural information and, in the OB approaches, the Simple Non-Iterative Clustering (SNIC) algorithm for the image segmentation step. We performed an initial RF optimization process finding the optimal number of decision trees through out-of-bag error analysis. We randomly distributed 1200 ground truth points and used 70% to train the RF classifier and 30% for the validation phase. This subdivision was randomly and recursively redefined to evaluate the performance of the tested approaches more robustly. The OB approaches performed better than the PB ones when using the 15 m L8 panchromatic band, while the addition of textural information did not improve the PB approach. Using the panchromatic band within an OB approach, we produced a detailed, 15-m resolution LULC map of the study area.


2012 ◽  
Vol 37 (4) ◽  
pp. 168-171 ◽  
Author(s):  
Birutė Ruzgienė ◽  
Qian Yi Xiang ◽  
Silvija Gečytė

The rectification of high resolution digital aerial images or satellite imagery employed for large scale city mapping is modern technology that needs well distributed and accurately defined control points. Digital satellite imagery, obtained using widely known software Google Earth, can be applied for accurate city map construction. The method of five control points is suggested for imagery rectification introducing the algorithm offered by Prof. Ruan Wei (tong ji University, Shanghai). Image rectification software created on the basis of the above suggested algorithm can correct image deformation with required accuracy, is reliable and keeps advantages in flexibility. Experimental research on testing the applied technology has been executed using GeoEye imagery with Google Earth builder over the city of Vilnius. Orthophoto maps at the scales of 1:1000 and 1:500 are generated referring to the methodology of five control points. Reference data and rectification results are checked comparing with those received from processing digital aerial images using a digital photogrammetry approach. The image rectification process applying the investigated method takes a short period of time (about 4-5 minutes) and uses only five control points. The accuracy of the created models satisfies requirements for large scale mapping. Santrauka Didelės skiriamosios gebos skaitmeninių nuotraukų ir kosminių nuotraukų rektifikavimas miestams kartografuoti stambiuoju masteliu yra nauja technologija. Tai atliekant būtini tikslūs ir aiškiai matomi kontroliniai taškai. Skaitmeninės kosminės nuotraukos, gautos taikant plačiai žinomą programinį paketą Google Earth, gali būti naudojamos miestams kartografuoti dideliu tikslumu. Siūloma nuotraukas rektifikuoti Penkių kontrolinių taskų metodu pagal prof. Ruan Wei (Tong Ji universitetas, Šanchajus) algoritmą. Moksliniam eksperimentui pasirinkta Vilniaus GeoEye nuotrauka iš Google Earth. 1:1000 ir 1:500 mastelio ortofotografiniai žemėlapiai sudaromi Penkių kontrolinių taškų metodu. Rektifikavimo duomenys lyginami su skaitmeninių nuotraukų apdorojimo rezultatais, gautais skaitmeninės fotogrametrijos metodu. Nuotraukų rektifikavimas Penkių kontrolinių taskų metodu atitinka kartografavimo stambiuoju masteliu reikalavimus, sumažėja laiko sąnaudos. Резюме Ректификация цифровых и космических снимков высокой резолюции для крупномасштабного картографирования является новой технологией, требующей точных и четких контрольных точек. Цифровые космические снимки, полученные с использованием широкоизвестного программного пакета Google Earth, могут применяться для точного картографирования городов. Для ректификации снимков предложен метод пяти контрольных точек с применением алгоритма проф. Ruan Wei (Университет Tong Ji, Шанхай). Для научного эксперимента использован снимок города Вильнюса GeoEye из Google Earth. Ортофотографические карты в масштабе 1:1000 и 1:500 генерируются с применением метода пяти контрольных точек. Полученные результаты и данные ректификации сравниваются с результатами цифровых снимков, полученных с применением метода цифровой фотограмметрии. Ректификация снимков с применением метода пяти контрольных точек уменьшает временные расходы и удовлетворяет требования, предъявляемые к крупномасштабному картографированию.


2015 ◽  
Vol 26 (1) ◽  
pp. 163-181 ◽  
Author(s):  
Ian G. Robertson

AbstractIn the 1960s, the Teotihuacan Mapping Project (TMP) focused an ambitious, multiyear survey program on the pre-Columbian urban center of Teotihuacan. In addition to creating a highly detailed map, the TMP made systematic records of surface remains and collected nearly one million artifacts from roughly 5,000 provenience tracts. Taken together, the spatial, descriptive, and artifactual data collected by the TMP still constitutes one of the most extensive and most detailed records in existence for any ancient city. This paper characterizes and provides an update on TMP surface observations, particularly as they exist in digital format. Several analytical case studies illustrate substantive ways in which these data have been used in the decades since the TMP survey to investigate the culture and history of ancient Teotihuacan. The utility of extensive surface survey data for investigating key urban organizational elements such as neighborhoods and social districts is briefly considered, along with the growing importance of the TMP collections and records as increasingly large parts of Teotihuacan are lost to urban sprawl and destructive agricultural practices.


2012 ◽  
Vol 256-259 ◽  
pp. 2279-2284
Author(s):  
Lian Ying Li ◽  
Zhang Huang ◽  
Xiao Lan Xu

A necessary updating degree is vital for the digital map data in a vehicle navigation system. Only when the digital map data are well updated, can the quality of the navigation be assured. Today the companies devoting to the production of digital map data for vehicle navigation have to cost much labor, material and capital to collect and update data in order to maintain a necessary updating degree. Throughout the history of electronic navigation data updating, they have made considerable progress both on the methods and processes of data production, and the way of map management. Updating from the CD to the network, from the wired to the wireless, from the replacing to the incremental way, each of the technical changes is a power source to enhance the data updating rate. As we all know, the change detection is a prerequisite and base for the electronic navigation data updating. By rapidly developing the area with changes and using the appropriate updating method, we can scientifically maintain the original database of navigation data and terminal physical data. In view of this, starting from application needs for dynamic data updating, this paper analyses change detection methods of navigation data in different versions used for generating incremental data, and focuses on that of rasterizing features and attributes, exploring a new approach to quickly get the incremental data between versions.


Itinerario ◽  
1995 ◽  
Vol 19 (3) ◽  
pp. 167-174 ◽  
Author(s):  
Bhaswati Bhattacharya

Both overseas trade and shipbuilding in India are of great antiquity. But even for the early modern period, maritime commerce is relatively better documented than the shipbuilding industry. When the Portuguese and later the North Europeans entered the intra-Asian trade, many of the ships they employed in order to supplement their shipping in Asia were obtained from the Indian dockyards. Detailed evidence with regard to shipbuilding, however, is very rare. It has been pointed out that the Portuguese in the sixteenth century were more particular than their North-European counter-parts in the following centuries in providing information on seafaring and shipbuilding. Shipbuilding on the west coast has been discussed more than that on the eastern coast of India, particularly the coast of Bengal. Though Bengal had a long tradition of shipbuilding, direct evidence of shipbuilding in the region is rare. Many changes were brought about in the history of India and the Indian Ocean trade of the eighteenth century, especially after the 1750s. When the English became the largest carriers of Bengal's trade with other parts of Asia, this had an impact on the shipbuilding in Bengal. It was in their interest that the British in Bengal had their ships built in that province.


1959 ◽  
Vol 10 (2) ◽  
pp. 150 ◽  
Author(s):  
AM Olsen

The maximum yield of the school shark fishery in south-eastern Australian waters was 4.09 million lb in 1949. The catch has fluctuated since then about a declining trend to 3.18 million lb in 1956. In 1944, 7.3 hooks were required to catch a shark of mean weight 14.7 lb. In 1956 the number of hooks required was almost doubled: 13.6 hooks were needed to catch sharks of mean weight 13.7 lb; the catch per hook dropped from 2.01 to 0.99 lb. Whereas the catch per boat-month remained relatively stable at 4765 lb for 1944 and 4643 for 1956, the number of hooks used per boat-month increased from 2366 to 4668 hooks in 12 years. Throughout this period the mean weight of sharks in eastern Bass Strait remained fairly steady (11-13 lb) whereas there was a drop of 3 lb from a mean weight of 17-20 lb in the predominantly mature portion of the stock in western Bass Strait. Fishermen in South Australia have reported a comparable drop in the mean weight of sharks in their catches. During the period 1941-46 there was unrestricted inshore fishing of juveniles and pregnant females with a consequent severe drop in the inshore population. The subsequent decline in the annual total catch is believed to be due not only to a too intensive offshore fishery but also to the resultant reduced recruitment and depressed reproductive potential caused by the earlier destruction of juveniles and pregnant females. In the data presented in this paper there is evidence that the school shark fishery, which is operating on a single stock of sharks with a slow growth rate, a late sexual maturity, and a low fecundity, shows trends which are suggestive of depletion. Because similar trends in the soupfin shark fishery of California and in the dogfish fishery of British Columbia were followed by depletion, it has been inferred that regulations to protect the vulnerable phases of the life history of the school shark of Australia may be required. Measures for conservation are discussed.


2018 ◽  
Vol 7 (11) ◽  
pp. 441 ◽  
Author(s):  
Zhenjin Zhou ◽  
Lei Ma ◽  
Tengyu Fu ◽  
Ge Zhang ◽  
Mengru Yao ◽  
...  

Despite increases in the spatial resolution of satellite imagery prompting interest in object-based image analysis, few studies have used object-based methods for monitoring changes in coral reefs. This study proposes a high accuracy object-based change detection (OBCD) method intended for coral reef environment, which uses QuickBird and WorldView-2 images. The proposed methodological framework includes image fusion, multi-temporal image segmentation, image differencing, random forests models, and object-area-based accuracy assessment. For validation, we applied the method to images of four coral reef study sites in the South China Sea. We compared the proposed OBCD method with a conventional pixel-based change detection (PBCD) method by implementing both methods under the same conditions. The average overall accuracy of OBCD exceeded 90%, which was approximately 20% higher than PBCD. The OBCD method was free from salt-and-pepper effects and was less prone to images misregistration in terms of change detection accuracy and mapping results. The object-area-based accuracy assessment reached a higher overall accuracy and per-class accuracy than the object-number-based and pixel-number-based accuracy assessment.


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