Abstract
The geometric accuracy of the Level lA product of Terra/MODIS has been investigated by comparing the contents of Latitude/Longitude file with GCPs. The investigation showed that the geometric accuracy by the systematic correction was a few kilometers on the ground. It is insufficient for land applications, especially for the use of 250m images. The system of the precise geometric correction based on the PANDA soft wares was developed. In the system, ‘bow-tie’effect, which is distinctive of MODIS, can be corrected and GCPs are extracted automatically by the template matching of image data and GMT coastal data. In the GCP extraction process, the template can be arrayed in either scanned image coordinates or map coordinates. And either the coastal lines or land/sea flag can be selected as the feature of the template. It was examined how efficient these selections are on the GCP extraction from 250m images. As the result, the system adopts the method of matching of land/sea flag in scanned image coordinates. Furthermore, the sensor alignment was modified using a number of GCPs. The modification improved the geometric accuracy of 250m images to about 1 pixel without GCPs.
