We report the countermeasure activities of the Geospatial Information Authority of Japan against the Great East Japan Earthquake in terms of monitoring of crustal deformation, grasping disasters by means of aerial photographs, photo interpretation, geographic analysis, providing related agencies with geospatial information, and others.
To grasp damages caused by the earthquake and tsunami, aeropohotographs were taken immediately, applying the agreement for the urgent air photographing between Geospacial Information Authority (GSI) and Association of Precise Survey & Applied Technology (APA). The APA investigated possibility of air photographing by registered companies according to the request of the GSI, the GSI decided the allotment area for each company based on the investigation, and each company took aerophotographs by contract with the GSI. The photographing was completed by the day after tomorrow. Examinations for more prompt photographing are seems to be indispensable.
We have developed a point-based rendering application with high-speed spatial interpolation using a point cloud to generate virtual reality (VR) data called LiDAR VR. This application can not only transform from a point cloud to VR data but can also regenerate missing point data in the rendered result from a selected viewpoint. Moreover, we have focused on the following features of the LiDAR VR generation. First, panorama imagery can be generated automatically from many viewpoints from one observation data set. Second, it is possible that a spatial interpolation with rendering results can reduce the processing task. These features have been verified using case studies.
In order to improve vicarious calibration accuracy in solar reflectance channels of radiometer onboard satellite, influences due to calibration accuracy of skyradiometer which allows aerosol refractive index and size distribution estimations together with influences due to size distribution estimation accuracy on vicarious calibration accuracy of spaceborne based visible and near infrared radiometers are clarified. It is found that 10% of estimate errors of aerosol refractive index and size distribution are corresponding to 1.3% of Top of the Atmosphere (TOA) radiance. It is also found that the difference between volume spectra of aerosol size distribution derived TOA radiance and Power law of Junge distribution derived TOA radiance is within 2%. Volume spectra of aerosol distribution requires heavy and large radiometer which allows measurement of solar direct, diffuse and aureole like skyradiometer while Junge distribution require just spectral optical depth measurements only with light and small measuring instrument.