Summary Journal of Geodesy and Cartography Vol 45 (9) year 2020.

Cập nhật : 02/04/2021
Lượt xem: 138

Applying machine learning torestore spectral band loss in satellite image

Pham Minh Hai   - Vietnam institute of geodesy andcartography

Nguyen Ngoc Quang - National Remote Sensing Department

Problems occur regularlyin spectral band of satellite image due to the satellite image acquisitionprocess. The quality of the image acquisition process still has a number ofproblems such as stripes  in spectralbands and image channel loss, which result in images do not  have enough 3 basic spectral bands: the RED-GREEN-BLUE (RGB). The objective of this study is to develop an approach torestore the satellite image bands using the correlation between the error bandwith the remaining ones. The Python programming in which "Backward Elimination"regression algorithm was used to calculate, analyze, and process data.


Proposalon technical requirements for aerial photography in using Continuous ReferenceStations (Cors)

Dao Ngoc Long - Vietnam Intitude ofGeodesy and Cartography

Vuong Trong Kha - Hanoi University ofMining and Geology

                                                                                       

Currently, the Cors in Vietnam have been built, which means thatconducting research into the use of the system for aerial photography isimportant to improve the efficiency of flight photography and investment. Thispaper presents aerial photography specifications when using Cors in order toidentify external elements of images for mapping and constructing geographicdatabase.


Landscape approach - basedwetland ecosystem mapping for Dong Thap Muoi region at 1:100.000 scale


Nguyen ThanhThuy - Vietnam institute of geodesy and cartography


Wetland ecosystem map is inputdata for assigning and assessing the biodiversity, functions, services, therisk pressures on, and the degradations of wetland ecosystems. The resultingmap is used to define the wetland ecosystems protection and restorationprioritie orders. This paper shows the landscape approach - based wetlandecosystem map establishment methodology, for Dong Thap Muoi region at 1:100.000scale for planning and managing at the regional and inter-provincial level,with the forming factors, are geology, soil, topography - geomorphology,climate - meteorology, hydrology-oceanography, vegetation, and land use status.


Determinationof mean sea surface used for boundary between land and sea and serving the seacadastral works

Ha Minh Hoa - Vietnam Institute of Geodesy andCartography

This article represents importance role of the mean low water surfacein management of coastland scape. At present the mean low water surface was notdeterminined and there is not base for development  of sea cadastral works. Detemination of themean low water surface will increase the sea cadastral works in MONRE.


A basis of proposal for surveyand mapping instrument list needs to be verified in Vietnam


Bui Dang Quang - Department of Survey, Mapping and Geographic information Vietnam

VuTien Quang - Vietnam Association of Geodesy Cartography and Remote Sensing


This article discusses on the verification of surveying andmapping equipment in Vietnam - a necessary issue but has not been fullyimplemented for many years, and also makes recommendations on verification ofsurveying and mapping equipment that need to be tested in the near future tostrengthen the state management of the measuring device verification in thedirection specified in the Law of Measurement No. 04/2011/QH13 and the Law onSurvey and Mapping No. 27/2018/QH14.



Estimatingand distribution mapping of moisture content of topsoils over the NorthernCentral Highlands of Vietnam using Sentinel 2A Imagery

Ngo Thi Dinh - Land management andrural development institute - Forestry University

Pham Quang Vinh -  The International Center for TropicalAgriculture (CIAT)

Nguyen Thi Thu Ha - University of Science,Vietnam National University

Thisstudy aims to estimate the soil moisture content (SMC) of topsoils over theNorthern Central Highland using the Sentinel 2A image basing on the developmentof a regional emprirical model for the estimation. Total 8 soil samplesrepresentating for 6 soil types in the study area were collected andsub-sampled into 80 samples with 10 interval SMC levels for each sample.Resultant soil spectral analysis indicated a high correlation of SMC and theratio of S2A band 8 (NIR, 865 nm) versus band 12 (SWIR2, 2190 nm), thereforethe SMC can be accurately estimated from the ratio with a logarithm function.Applications of the model into estimating SMC from 30 S2A scenes acquired overthe study area in March 5 years, since 2016 to 2020, show that the 2016 droughtis severer than the other year droughts. In March 2016, a one-third of thestudy area was coverered by topsoils with SMC lower than 25 %. The attention onthe correlation between SMC in topsoils which are coverered by vegetation andun-vegetation should be focused in the future for futher application in theagricultural drough management.


Integrating IMU and GNSS devices to receive data usingvirtual reference station technology (VRS) on unmanned aerial vehicles (UAVs)for topographic mapping.

Luu Hai Au, Đang Xuan Thuy, Ngo Thi Lien - Vietnam institute of geodesy andcartography


The topographic mapping application ofunmanned aerial vehicles (UAV) has been applied and is gradually becoming morepopular. Determining the exact factors external orientation of photos is one ofthe factors determining the accuracy of topographic maps should be establishedinstead of setting the image control network. This article discusses the issueof integrating GNSS-IMU devices on unmanned aerial vehicles (UAVs) incombination with virtual reference station technology (VRS) to identifyoutward-facing elements of an image with accurately ensure the creation of alarge scale terrain map with the maximum number of image control points.


Estimatingsoil salinity of agricultural soil in some areas near the estuaries of HaiPhong – Thai Binh provinces using Sentinel 2A imagery

Le Thi Thu Hien1, Pham Minh Hai2,Nguyen Thanh Binh1, Nguyen Ngoc Thang1

Instituteof Geography, Vietnam Academy of Science and Technology

VietnamInstitute of Geodesy and Cartography

In recent years, the complexity of the downstream flow indry season in combination with the increasing demand for water of differenteconomic sectors... has led to the increasing salinity intrusion in some coastalareas of the Red River delta. This study evaluated soil salinity at theestuaries of the Van Uc, Thai Binh and Tra Ly rivers using Sentinel 2A data.Sentinel 2A data were used to extract indices including single spectral band,VSSI, SAVI, NDVI, and NDSI index. Statistical analyses between conductivity (EC1:5,dS/m) and indices were performed. The results show that the spectral values​​of the near infrared band and the VSSI index strongly correlate with EC1:5(with correlation coefficients of 0.75 and 0.63, respectively). The comparisonshows that the soil salinity estimated from Sentinel 2A data is consistent withfield data (with R2 = 0.74 and RMSE = 3.36 dS/m for the spectralband NIR and R2 = 0, 67 and RMSE = 3.8 dS/m for the VSSI index). Theresults of this study demonstrate that Sentinel 2A data has high potential formonitoring the salinity of the topsoil. Moreover, the study results are usefulfor agricultural activities, providing important information to authorities andfarmers by mapping soil salinity as a basis for better crop choices to reduceeconomic losses in the context of climate change.


Research onidentification of status poles for urban residential land prices
in Cau Giay Districtaccording to Status – Quality Trade Off (SQTO) approach

Bui NgocTu, Le Phương Thuy, Pham Le Tuan, Tran Quoc Binh

Faculty of Geography, VNU University of Science, 334 Nguyen Trai, Hanoi, Vietnam

Evaluating residential land prices plays an important role in the financial management.Currently, there are different approaches to evaluate residential land prices, including the one that uses Status – Quality Trade Off (SQTO) theory. Identifingstatus poles is an important step in the land valuation method based onSQTO approach. This study aims to identify status poles for urbanresidential land prices in Cau Giay District. With 452 samples collected inrecent years and proposed 20 factors affecting land price, the authors havepointed out two status poles urban residential land prices, namely CauGiay park and Trung Hoa - Nhan Chinh new urban area.


Solutions of fixed virtual reference stations using network of continuouslyoperating reference stations of  Vietnam

Lai Duc Truong*, Duong Thanh Trung,Pham Minh Duc, Bui Ngoc Quyen.

 Hanoi University ofMining and Geology

Today,Global Navigation Statellite System(GNSS) technology is widely used insurveying, from the establishment of control network  to collecting measurements of topographic andcadastral maps. Real-time kinematic positioning (RTK) technology is commonlyused for collecting geographical data. RTK technology using a network ofpermanent reference stations (NRTK) is being applied with many advantages suchas ensuring continuity, on a national scale and stable accuracy of centimeter.The advantages of RTK technology have been proven through research andpractical tests. However, such technology also has the problem that it can onlybe measured within the network's range, out of the region will not be possible.To overcome this problem, this paper proposes solutions for RTK measurementoutside the NRTK boundary area based on the principle of fixed VirtualReference Station. Experiments were conducted in some coastal areas of Vietnamwith the network of CORS. The results show that the proposed method overcomesthe lack of coverage of the VNGEONET network in coastal and border areas thatconventional RTK method cannot implement.


Development of e-land registration system model for Tu SonTown,

Bac Ninh Province

Trinh Thi Kieu Trang, Bui Ngoc Tu, Doan Quang Cuong

Faculty of Geography, VNU University of Science, 334Nguyen Trai, Hanoi, Vietnam

The government of Vietnam highlightsthe importance of effective and sustainable land management and improvedgovernance. Since 2008, some efforts have been undertaken to develop landrecords and databases. Despite much progress, fundamental bottlenecks in theland administration sector remain. There are still many shortcomings in theVietnamese land administration system, especially in the land registrationsystem. A study on the improvement of the land registration system is necessaryin the context that the government of Vietnam is trying to build amulti-purpose land information system. The research purpose was to improve theefficiency and transparency of land administration services by developing theland registration system in Tu Son town, Bac Ninh Province. This research usedsurvey methods, data analysis (qualitative analysis), statistical methods,comparison, and expert methods. This research results have proposed the newelectronic land registration system that can improve the multi-purpose landmanagement system for Tu Son, Bac Ninh in particular and in general in Vietnam.