• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.37 no.6
• /
• pp.525-533
• /
• 2019

There are two feature collection methods in digital mapping using the UAV (Unmanned Aerial Vehicle) Photogrammetry: vectorization and stereo plotting. In vectorization, planar information is extracted from orthomosaics and elevation value obtained from a DSM (Digital Surface Model) or a DEM (Digital Elevation Model). However, the exact determination of the positional accuracy of 3D features such as ground facilities and buildings is very ambiguous, because the accuracy of vectorizing results has been mainly analyzed using only check points placed on the ground. Thus, this study aims to review the possibility of 3D spatial information acquisition and digital map production of vectorization by analyzing the corner point coordinates of different layers as well as check points. To this end, images were taken by a Phantom 4 (DJI) with 3.6 cm of GSD (Ground Sample Distance) at altitude of 90 m. The outcomes indicate that the horizontal RMSE (Root Mean Square Error) of vectorization method is 0.045 cm, which was calculated from residuals at check point compared with those of the field survey results. It is therefore possible to produce a digital topographic (plane) map of 1:1,000 scale using ortho images. On the other hand, the three-dimensional accuracy of vectorization was 0.068~0.162 m in horizontal and 0.090~1.840 m in vertical RMSE. It is thus difficult to obtain 3D spatial information and 1:1,000 digital map production by using vectorization due to a large error in elevation.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.11a
• /
• pp.173-178
• /
• 2004

This paper presents photogrammetric processing to generate digital elevation models and deals with the accuracy potential of SPOT-5 HRG supermode imagery for DEM generation. The DEMs obtained from digital topographic maps of 1/5000 scale were used as the refernce DEM data. DEMs extracted from HRG dats were compared with digital topograpic map DEMs on severed test sections. And digital surface model(DSM), refering to above the ground like buildings, was produced about the test built-up area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.1
• /
• pp.23-30
• /
• 2015

A shoreline mapping is essential for describing coastal areas, estimating coastal erosions and managing coastal properties. This study has planned to map the 3D shorelines with the airborne LiDAR(Light Detection and Ranging) data and the KOMPSAT-2 imagery, acquired in Uljin, Korea. Following to the study, the DSM(Digital Surface Model) is generated firstly with the given LiDAR data, while the NDWI(Normalized Difference Water Index) imagery is generated by the given KOMPSAT-2 imagery. The classification method is employed to generate water and land clusters from the NDWI imagery, as the 2D shorelines are selected from the boundaries between the two clusters. Lastly, the 3D shorelines are constructed by adding the elevation information obtained from the DSM into the generated 2D shorelines. As a result, the constructed 3D shorelines have had 0.90m horizontal accuracy and 0.10m vertical accuracy. This statistical results could be concluded in that the generated 3D shorelines shows the relatively high accuracy on classified water and land surfaces, but relatively low accuracies on unclassified water and land surfaces.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.38 no.1
• /
• pp.43-48
• /
• 2020

Open pit mines for limestone mining require rapid development of technologies and efforts to prevent safety accidents due to rapid deterioration of the slope due to deforestation and rapid changes in the topography. Accurate three-dimensional spatial information on the terrain should be the basis for reducing environmental degradation and safe development of open pit mines. Therefore, this study constructed spatial information about open pit mine using UAV(Unmanned Aerial Vehicle) and analyzed its utility. images and 3D laser scan data were acquired using UAV, and digital surface model, digital elevation model and ortho image were generated through data processing. DSM(Digital Surface Model) and ortho image were constructed using image obtained from UAV. Trees were removed using 3D laser scan data and numerical elevation models were produced. As a result of the accuracy analysis compared with the check points, the accuracy of the digital surface model and the digital elevation model was about 11cm and 8cm, respectively. The use of three-dimensional geospatial information in the mineral resource development field will greatly contribute to effective mine management and prevention of safety accidents.

• Journal of Environmental Impact Assessment
• /
• v.22 no.1
• /
• pp.99-107
• /
• 2013

This study is an impact assessment of building blocks on urban inundation depth and area. LiDAR data is used to generate two original data set in terms of DEM with $5{\times}5$ meter and building block elevation layer of the study drainage area in Cheongju and then the building block elevation layer is modified again to the mesh data with same size to DEM. Two-dimensional inundation analysis is carried out by applying 2D SWMM model. The inundation depth calculated by using the building block elevation layer shows higher reliability than the DEM. This is resulted from the building block interference to surface flow. In addition, the maximum flooded area by DEM is two times wider than the area by building block layer. In the case of the surface velocity, the difference of velocity is negligible in either DEM or building block case in the low building impact zone. However, If the impact of building on the surface velocity was increase, the gap of velocity was significant.

• BMB Reports
• /
• v.38 no.6
• /
• pp.695-702
• /
• 2005

The groESL bicistronic operon of a restricted facultative methylotrophic bacterium Methylovorus sp. strain SS1 DSM 11726 was cloned and characterized. It was found to consist of two ORFs encoding proteins with molecular masses of 11,395 and 57,396 daltons, which showed a high degree of homology to other bacterial GroES and GroEL proteins. The genes were clustered in the transcription order groES-groEL. Northern blot analyses suggested that the groESL operon is transcribed as a bicistronic 2.2-kb mRNA, the steady-state level of which was markedly increased by temperature elevation. Primer extension analysis demonstrated one potential transcription start site preceding the groESL operon, which is located 100bp upstream of the groES start codon. The transcription start site was preceded by a putative promoter region highly homologous to the consensus sequences of Escherichia coli ${\sigma}^{32}$-type heat shock promoter, which functioned under both normal and heat shock conditions in E. coli. Heat shock mRNA was maximally produced by Methylovorus sp. strain SS1 approximately 10min after increasing the temperature from 30 to $42^{\circ}C$. The groESL operon was also induced by hydrogen peroxide or salt shock.

• Aerospace Engineering and Technology
• /
• v.11 no.1
• /
• pp.118-125
• /
• 2012

The purpose of this study is to analyze the ortho image quality change according to the generation technique of Digital Elevation Model(DEM) based on the digital map. First of all, two different types of DEM were generated using contour layer(Case1), contour layer and altitude layer(Case2) from the digital map on the scale of 1/5,000. After generating and evaluating two types of DEM, KOMPSAT-2 ortho images were generated by using them. In conclusion, Case2 DEM was more effective to use in the slope and switchback area, on the other hand, Case1 DEM was much better than Case2 DEM for preventing a topographic distortion in flat area.

• Journal of Korean Society for Geospatial Information Science
• /
• v.14 no.4 s.38
• /
• pp.61-70
• /
• 2006

This paper presents photogrammetric processing to generate digital elevation models using SPOT-5 HRG stereo images and deals with the accuracy potential of HRG (High Resolution Geometry) supermode imagery for DEM generation. After bundle adjustment was preformed for sensor modelling, digital surface models were generated through the procedures of Epipolar image resampling and image matching. The DEM extracted from HRG imagery was compared along several test sections with the the refernce DEM which was obtained from the digital topographic maps of a scale of 1 to 5000. The ratio of the zone with DEM errors less than 5m to the whole zone was 53.8%, and about 2.5m RMSE was showed when assuming that the zones larger than 5m were affected by clouds, water bodies and buildings and excluding those zones from accuracy evaluation. In addition, the three-dimensional bird's eye view model and 3D building model were producted based on the DSM which was extracted from SPOT-5 HRG data.

• Proceedings of the KSRS Conference
• /
• v.2
• /
• pp.590-593
• /
• 2006

Timber inventory management includes to measure and update forest attributes, which is crucial information for private companies and public organizations in property assessment and environment monitoring. Field measurement would be accurate, but time-consuming and inefficient. For the reason, remote sensing technology has been an alternative to field measurement from an economic perspective. Among several sensors, LiDAR and Radar interferometry are known for their efficiency for forest monitoring because they are less influenced by weather and light conditions, and provide reasonably accurate vertical/horizontal measurement for a large area in a short period. For example, Shuttle Radar Topography Mission (SRTM) and National Elevation Dataset (NED) in the U.S. can provide tree height information and DSM. On the other hand, LiDAR DSM (the first return) and DEM (the last return) can also present tree height estimation. With respect to project site of loblolly pine plantation in Louisiana in the U.S., the accuracy of SRTM C-Band approach estimating tree height was assessed by the LiDAR approaches. In addition, SRTM X-Band and NED were also compared with the results. Plantation year in inventory GIS, which is directly related to forest age, is high correlated with the difference between SRTM C-Band and NED. As a byproduct, several stands of age mismatch could be recognized using an outlier detection algorithm, and optical satellite image (ETM+) were used to verify the mismatch. The findings of this study were (1) the confirmation of usefulness of the SRTM DSM for forest monitoring and (2) Multi-sensors- Radar, LiDAR, ETM+, MODIS can be used for accuracy improvement of forest inventory GIS altogether.

• Journal of Forest and Environmental Science
• /
• v.33 no.3
• /
• pp.187-196
• /
• 2017

The use of unmanned aerial vehicles (UAV) for the estimation of tree height is gaining recognition. This study aims to assess the effectiveness of tree height estimation of Pinus densiflora Sieb. et Zucc. and Pinus koraiensis Sieb. et Zucc. using digital surface model (DSM) generated from UAV-acquired imageries. Images were taken with the $Trimble^{(R)}$ UX5 equipped with Sony ${\alpha}5100$. The generated DSM, together with the digital elevation model (DEM) generated from a digital map of the study areas, were used in the estimation of tree height. Field measurements were conducted in order to generate a regression model and carry out accuracy assessment. The obtained coefficients of determination (R2) and root mean square error (RMSE) for P. densiflora (R2=0.71; RMSE=1.00 m) and P. koraiensis (R2=0.64; RMSE=0.85 m) are comparable to the results of similar studies. The results of the paired two-tailed t-test show that the two tree height estimation methods are not significantly different (p-value=0.04 and 0.10, alpha level=0.01), which means that tree height estimation using UAV imagery could be used as an alternative to field measurement.