We analyze and evaluate a correlation of total coliform and land use data on a monthly basis in the downstream of Oita River. In addition,we analyze and evaluate the optimal range to use laser profiler data from the total coliform's observation points. As a result of the analysis, we found that the correlation of building land is high in land use, and the correlation of total coliform of March and June is high in the case of using land use data of about 2.0 km radius.
In the last few years, SfM (Structure from Motion) based on photographs taken from UAV (Unmanned Aerial Vehicle) has attracted a tremendous amount of interest for the creation of DSM (Digital Surface Model) and other morphometric products. However, the accuracy of the derived DSM hasn't been sufficiently evaluated yet. Therefore, the present contribution aims to compare UAV-based SfM data against TLS (Terrestrial Laser Scanning) derived DSM data. The fieldwork was carried out on a wave-cut bench in Kanagawa Prefecture (Japan). Results have indicated that DSM data derived from UAV-SfM can create a point cloud of comparable density to the one created by TLS, with a maximum deviation of 10 cm from the TLS data. The UAV-SfM technique has a great potential for a wide range of application, because of its high data accuracy, low acquisition and operational costs, allowing high spatial and temporal data recording.
Currently, a DEM (Digital Elevation Model) of high density range has been able to be created by spread of airborne laser scanner. However, when the DEM is created, the points of the DEM can not be interpolated accurately in some cases. Therefore, we propose a method of accurately interpolating the points of the DEM. The proposed method is performed by using iterative bilateral filter. Through the experiments using the DEM of 5m mesh, we demonstrate the effectiveness of our interpolation method.
We develop a shelter selection method for evacuating to a high place than the hight of the giant tsunami. Features of our method are to consider the evacuation time, the intrusion direction of the tsunami and the three-dimensional relationship of the various geospatial data. To evaluate the performance of our method, we conduct experiments using the data in Misa Oita-shi.
Recently, point cloud data are required for information management in civil engineering fields. Although massive point cloud data can be acquired using 3D scanner, such as a laser scanner, additional measurements are essential to fill 3D points in missing areas. Therefore, we proposed a point cloud integration methodology using a portable Time-of-Flight camera.
Conventional photo retrieval approaches were inefficient to find significant photos in ground-based monitoring using a large amount of photos taken after The Great East Japan Earthquake. Therefore, we focused on a new photo retrieval methodology improve the efficiency in a disaster monitoring. Our methodology is consisted of a photo geocoding using GPS and magnetic sensor data, geospatial arrangement of geocoded photos, and georeference rectification based on Scale-Invariant Feature Transform. Moreover, we have confirmed that our methodology can facilitate control and browsing of geocoded photos.