Summary Journal of Geodesy and Cartography Vol 47 (3) year 2021

Cập nhật : 06/05/2021
Lượt xem: 81

UNIFIED GRAVITY ANOMALIES CALCULATION METHOD FOR RESOURCE AND ENVIRONMENTAL TASKS

Le Anh Dung, Nguyen Phi Son - Institute of Geodesy and Cartography

Nguyen Van Sang - Hanoi University of Mining and Geology

Nguyen Huy Tung - land registration office of Khanh Hoa province

The Faye and Bouguer are very important in Geodesy and Geophysic. However, The Faye and Bouguer gravity anomalies have their own treatment, calculation and application. They have the same concept but different calculation methods and original reference so their anomalies values are different. Therefore, the resource and environmental tasks are impossibale to use the gravity anomaliesdata together. In this article, The authors point out the difference of the anomaly between two fields and propose a solution that is consistent with the general theory of anomaly for two fields; Proposing unified height reference system in the correction of gravity anomalies. Then, improving efficiency in calculating Faye and Bouguer gravity anomalies in natural resources and the environment tasks in Vietnam.


DETAILED ALGORITHM FORREMOTE SENSING IMAGES CLASSIFICATION BY MULTI-LAYERED ARTIFICIAL NEURALNETWORKS

Nguyen Du Khang, Nguyen Thi Thanh Binh

National Remote Sensing Department, MONRE

With the rapid development of remote sensing data acquisition and storage methods, today, abig data need to be processed and analyzed. These data are so large that the capabilities of the experts are no longer sufficient, leading to the continual increase in demand for automated data analysis methods. Application ofartificial neural networks is one of the solutions to solve the above problem.The paper proposes a detailed algorithm for training multi-layered neuralnetworks and remote sensing image classification application. Experimental results and evaluation of accuracy show that this method is quite feasible andsimple to semi-automate the classification of objects represented on remotesensing images, for the establishment and updating of data national geospatialdata.


SOLUTION FOR CORRECTING ELEVATION AND COORDINATE MEASURED BY GNSS/CORS TECHNOLOGY WHEN COMBINED WITHTRADITIONAL MEASUREMENT METHOD IN LARGE SCALE  MAPPING.

Hoang Thi Thuy, Hanoi University of Mining and Geology, Vietnam

In large-scale mapping, method of using electronic total stations (TS) can provide the mostreliable results, especially in residential areas and vegetated areas. Meanwhile, GNSS/CORS technology has advantage of achieving fast results and itis very efficient in a well-ventilated area. In order to take advantage ofthese two methods, we propose the application of the coordinate and elevation adjustment problem to calibrate the map established by using GNSS/CORS technology on the map established by TS by using ground control points or clearfeature points. In case of using GNSS/CORS for mapping, it is necessary to useTS to measure obscured points, these points can be measured in the assumed coordinate system, then use TS to measure some clear feature points which was determined by GNSS/CORS, these can be used as key points to match the area measured by TS to the area measured by GNSS/CORS. The result of the study is aprogramming module which can automatically correct the coordinate and elevationof the measured points when applying the combination of GNSS/CORS and TS formapping. The experimental results showed that the proposed method can beapplied for establishing topographic and cadastral maps from data derived by integrating GNSS/CORS and TS.


TEST PROCEDURE OF THECOORDINATES MEASURED BY THE ELECTRONIC TOTAL STATION

Bui Dang Quang, Department of Survey, Mapping and Geographic Information Vietnam

Nguyen Van Sang, Hanoi University of Mining and Geology

Nguyen Thi Thanh Huong, Vietnam Institute of Geodesy and Cartography

Before eachproject or periodically the electronic total station must be test to assesswhether it responses the requirements of the project. One of the measurementsof the total station is the coordinates. In Vietnam, there is no research workon test procedure of these measurement results. This paper presents the testprocedure of the coordinates measured by the electronic total station. The testprocedure is researched in detail from the configuration of the test field, themeasurement and the calculation steps. This test procedure is in accordancewith international standards. The test coordinates were performed with theSokkia SET 520K electronic total station. The experimental results show thatthe experimental standard deviation of coordinates reaches ± 0.8 mm.


STUDY OF THE TECHNOLOGICALPROCESS FOR BUILDING 3D CITY MAP ON WEB

Mai Dinh Sinh,Trinh Le Hung,

Military Technical Academy, Hanoi, Vietnam

Vuong Trong Kha, Hanoi University of Mining and Geology, Hanoi, Vietnam

With thestrong development of science and technology, web-based mapping applicationshave shown superior advantages over traditional map representation methods. Thepaper discusses methods and steps taken to build a 3D geospatial informationsystem. The main objective of this study is to propose the process of creatinga 3D virtual city map on the Web. Key steps in the process include gatheringgeospatial information, building 3D models, and visualizing 3D city-based citydata. Building 3D virtual city application on Web based on 3DCityDB platform. Itis an open source software package that allows efficient storage, management,and display of 3D city models in CityGML format. The test results show that theapplication of open source to create 3D virtual maps on the Web has manyadvantages such as saving time, cost and utilizing many existing data sourcesin building applications. 3D virtual city data mining application.


MONITORING OF WATER LEVELVARIATIONS IN MEKONG DELTA BASIN USING SAR ALTIMETER DATA

Nguyen Ha Phu, Nguyen Ngoc Nam

National Remote Sensing Department

Nguyen Trong Truong Son

Hanoi University of Natural Resources and Environment

Monitoring ofwater level variations is essential for water resource management. Currently,the application of the Synthetic Aperture Radar (SAR) altimetry technologyallows to improve the accuracy as well as the ability to monitor the waterlevel variations of smaller rivers and lakes. The content of this paper is toevaluate the possibility of monitoring water level variations in the MekongRiver basin using data Jason-3 and Sentinel-3A. The results show that incomparison with the time-series of water level variations from the In-Situhydrological data, the accuracy of the time-series of water level variationsfrom satellite altimeter data can be achieved from 0.15 m to 0.20 m underfavourable conditions, however, the measurement performance in slopemountainous areas is still limited in dry season and the cycles with no validdata are sometimes in long periods of time.


PROPOSAL ON TECHNOLOGICALPROCESS FOR IDENTIFYING UNDERGROUND DISCHARGE OBJECTS BY USING GEORADAR (GPR)RIS MF HI-MOD #4 EQUIPMENT

Nguyen Van Chuc, Duong Van Trien, Luong Thi Hanh

Institute of Geodesy and Cartography

A number ofresearch studies and regulations in some countries in the world and in Vietnammainly focus on identifying and justifying underground objects for the purposeof mapping underground infrastructure as well as some specialized objects. The definition of ‘underground discharge objects’ has a non-transparent meaning and their construction is not particularly included in the design of factories and industrial zones. This paper introduces the process of detecting underground objects in the discharge operation as the result achieved by State-level research project. Code: CS.2020.07.


RESEARCH TO DETECT, RAPIDASSESSMENT OF LAND COVER CHANGE FOR UPDATING GEOGRAPHIC DATABASES AT SCALE1:10.000

Pham Thi Hong Le, Pham Ngoc Phat, Tran Quang Minh

Department of Survey, Mapping and Geographic information Vietnam

Pham Ngoc Minh Anh

National Economics University

The paper presents the results of research and application of rapid and highly effectivedetection and assessment solutions on the amount, extent of land cover change serving the formulation of technical design - cost estimation of a project for updating the database using SPOT 6/7 images and the 2009 national geographic database. The authors convert the base geographic data from vector format toraster format combining classification, grouping, then use change detection technique based on multi-spectral image classification technique to creatematrix of changes.  The process ofdetecting and assessment of changes in geographical objects is carried out in Hung Tay commune, Hung Nguyen district, Nghe An province.

USER NEEDS ASSESSMENT INBUILDING REGULATIONS ON SHARING OF INFORMATION, DATA AND PRODUCTS OF SURVEYINGAND MAPPING

Dong Thi Bich Phuong

Vietnam Intitude of Geodesy and Cartography

The articleclarifies the role of user needs assessment in spatial data policy andregulations development and presents the results of user needs assessment onsharing information, data and products of surveying and mapping.


USING LANDSAT 8 SATELLITEIMAGE DATA TO ASSESS CALCULATE ENVIRONMENTAL PARAMETERS IN BAC NINH PROVINCE INTHE PERIOD 2013 - 2015 - 2017

Vu Duong Thuy, Nguyen Truong Son

National Remote Sensing Department

The papersummarizes the results of using Landsat 8 satellite images to identify some keyenvironmental components of Bac Ninh province in the period 2013 - 2015 - 2017.Using Landsat 8 satellite images taken in 2013, 2015 and 2017 with linearinterpolation and regression methods to assess surface water quality(calculating 3 parameters BOD5, COD and TSS) and air quality (PM10 dust and APIair index). Research results show that pollution levels in Bac Ninh provincegradually increase in the period 2013 - 2015 - 2017. The application of freeLandsat 8 image sources in calculating water and air quality indicators forhigh efficiency and cost saving.