CC BY
39
УДК 528.91:551.21.3 Emil R. Bayramov
Geography Institute of Azerbaijan National Academy of Sciences
RESEARCH OF THE NEW GIS METHOD FOR THE PREDICTION OF CASPIAN SEA FLUCTUATION IMPACTS ON THE PROTECTED AREAS LOCATED ALONG COASTAL LINE FOR THE ENVIRONMENTAL MONITORING PURPOSES
Abstract:
The present day water level fluctuations of the Caspian negatively affect on protected area located along Coastal Line. For the Caspian Sea costal areas, it is highly important to make correct planning of future coastal infrastructure and prediction of possible emergencies as a result of Caspian Sea water level fluctuation. The main objective of this research is to present the up-to-date developed method of how to predict the Caspian Sea Level fluctuation impact on the coastal areas by monitoring visually results of Geographical Information System processing analysis based on the accurate spatial data acquired from highresolution stereo satellite imagery. As a result of this research it was calculated the forecast what coastal areas of Absheron National Park will be flooded in cases of Caspian Sea water level rises.
ИССЛЕДОВАНИЕ НОВОГО ГИС МЕТОДА ДЛЯ ПРОГНОЗИРОВАНИЯ КОЛЕБАНИЯ КАСПИЙСКОГО МОРЯ НА ПРИБРЕЖНЫЕ ОХРАНЯЕМЫЕ ПРИРОДНЫЕ ЗОНЫ С ЦЕЛЬЮ МОНИТОРИНГА ОКРУЖАЮЩЕЙ СРЕДЫ
Резюме:
На сегодняшний день колебание водного уровня Каспийского моря отрицательно влияет на особо охраняемые территории, расположенные вдоль прибрежной линии. Для прибрежных зон Каспийского моря очень важно проводить правильное планирование прибрежных инфраструктур и прогнозирование возможных отрицательных процессов в результате колебания уровня воды. Целью исследования является разработка методики для прогнозирования воздействий колебаний Каспийского Моря на прибрежные зоны посредством мониторинга результатов геоинформационной обработки космических стереоизображений с высокой разрешающей способностью и полученных по ним высокоточных пространственных данных. В результате были выявлены участки, которые могут быть затоплены при повышении уровня моря.
Introduction
Caspian Sea Fluctuations are periodic which are caused by various natural factors what makes negative impacts on the strict nature reserves, sanctuaries and national parks located along coastal line of Caspian Sea. It is very important to make correct planning of future coastal infrastructure and prediction of possible accidents. For the realization of these goals it is inevitable to make appropriate reliable instrument working with accurate technological principles and supporting decision makers in their everyday activities related with the sustainable development of coastal zones.
Materials and Methods
As the territory of the research was taken the eastern part of Absheron peninsula called Shakhova Kosa where is locate Absheron National Park represented in Fig. 1. Source materials used for accurate precise stereo model, digital elevation model and digital orthophoto map preparation are represented below:
1m high-resolution IKONOS Standard Stereo Imagery (EPIPOLAR) - PanSharpened Multispectral (PSM), Bands: Red, Green, Blue and Near Infrared. Standard accuracy of the source IKONOS stereo satellite imagery is approximately the following: Horizontal - ±11.5 m (RMSE), Vertical - ±13m (RMSE).
Fig. 1: Research Area
For the improvement of accuracy of standard stereo product to the level of precision stereo and application of prepared products it was important to pass the photogrammetric processing stages as Collection of Ground Control Points, Triangulation of stereo satellite imagery, Automatic DTM Generation, Interactive DTM Editing, Orthorectification and Quality Control of all products for the modeling of potential coastal line fluctuation.
STAGE 1: Collection of Ground Control Point
Preliminary planned positions of Ground Control and Check Point were identified in office conditions based on the standard stereo products for easier and exact planning of well visible point on the both of images of stereo pair for the further measurements by high-accuracy GPS systems. Accuracy, of measured GCP point met the following standards: Horizontal accuracy: 0.1 m (1- a) in each of horizontal directions, Vertical accuracy: 0.1 m (1- a) in vertical direction For the measurement was used the GPS Receiver with following parameters: 2 frequency 24 canal Real Time (Leica RS530) where one GPS was in the role of base and the second in the role of GPS-rover.
STAGE 2: Triangulation and creation of Precise Stereo Model
The triangulation process is important for the improvement of original accuracy of Stereo Model, which is approximately the following: Horizontal -±11.5 m (RMSE), Vertical - ±13m (RMSE), by refining IKONOS satellite imagery supported vendor-provided rational polynomial coefficients. This process was done using preliminary collected Ground Control and Check points along with the using of tie point calculated employing area-based matching using normalized correlation coefficients based on the images of stereo pair. As a result of the triangulation IKONOS epipolar imagery achieved the following accuracy: Horizontal - ±1 m (RMSE), Vertical - ±2m accuracy (RMSE). The process of
triangulation was conducted using Leica photogrammetry suite software orthobase environment.
STAGE 3: Automatic Digital Terrain Model Generation and Interactive DTM Editing
Generation of Digital Terrain Model was implemented based on the preliminary triangulated Stereo Model with improved accuracy using special Automatic Terrain Extraction mechanism working based on the area based image matching mechanism. Image matching refers to the automatic identification and measurement of corresponding image points that are located on the overlapping area of multiple images. But taking into account the possibility of correlation errors there is the necessity for additional interactive terrain editing using stereo plotting techniques working in the stereo mode. Afterwards, based on the all three dimensional spatial data was generated triangular regular network which is later being converted to Grid Format flexible in usage with resolution of 1m.
STAGE 4: Orthorectification
This stage is implemented for the removal of relief distortions available in the satellite imagery and the important role in this process plays accurate Digital Terrain Model. The effects of topographic relief displacement are accounted for by utilizing a Digital Terrain Model during the orthorectification procedure.
The accuracy of digital orthophoto map was controlled by the used in the triangulation ground control and check points and as a result of quality control it was calculated that digital orthophoto map accuracy reached - ±2 m (RMSE).
STAGE 5: Modeling of Caspian Sea level fluctuation by automatic interpolation
The accurate Digital Terrain Model affords us easily to interpolate the sections of the relief with the required height interval and represent the interpolation results in the linear form (Fig.2) what can be overlaid over the accurate digital orthophoto map obtained in the different periods as it is shown in Fig.3. The visualization modeling of the resulted interpolated data is possible both in two and three dimensional modes. This is the basic mechanism necessary for the modeling of the potential flooding of the costal areas. Based on these results it is easily possible to calculate area of the potentially flooded area represented in Fig.4 and Fig.5 with potential level rises to -27 and -28 height levels. Total area of the research is 7.62 sq. km where in case of level rise to -27 will be flooded 2.48 sq. km, and in case of level rise to -26 will be flooded 4.11 sq. km.
Fig.2 Interpolated Digital Terrain Model
Fig.3 Overlay of Interpolated
Sections data over satellite imagery
F ig.4 Flooding of the research area in case F ig. 5 Flooding of the research area in
case
of Caspian Sea level rise to -27 height level of Caspian Sea level rise to -26 height
level
Concussions:
The results of this research present that the processing of high-resolution stereo satellite imagery and preparation of precise stereo model, digital terrain models and digital orthophoto maps are absolutely suitable for the environmental modeling of potential Caspian Sea water level fluctuations. It means that it is possible to transform this photogrammetric methodology into the technological form that can be used by the decision makers and all other parties involved in the activities related with the coastal management. The high-resolution satellite imagery satisfied the needs of coastal environmental management giving almost the same results as aerial photography. Besides nowadays acquisition of satellite imagery is easily accessible periodically what gives possibility for the permanent tracking of coastal line change dynamics. Using the advantages of high-resolution satellite imagery it is possible to extract majority of all relief topographical details along the coastal areas and over whole territory using stereo plotting techniques what is very important for the further Geographical Information Systems modeling of the potential Caspian Sea fluctuation.
References:
An Introduction to the Caspian Sea and the Caspian Environment Programme, Page 16, III. Challenges to be Addressed, Sea Water Level Fluctuation.
Leica Geosystems, IKONOS Sensor Model Support our Guide, Page 1, Introduction to IKONOS Sensor Model Support.
Leica Geosystems, ERDAS Field Guide, Page 303, 304, Orthorectification.
Journal of Photogrammetry Engineering & Remote Sensing, Article: Geometric Processing of IKONOS Geo Stereo Imagery for Coastal Mapping Application, Kaichang Di, Ruijin Ma and Ron Li.
© EmilR. Bayramov, 2007
