The experimental results showed the accuracy successfully met the requirement of 1:5,000 topographic map in Korea. The accuracy of the resulted topographic maps was checked using ground truth data such as GNSS (Global Navigation Satellite System)-surveyed points over the accessible area and GCP chips in the inaccessible area, respectively. Through the stereo display quality assessment, we selected the optimal stereo set for each site. Then they are used for the epipolar resampled images that can be used for stereo-plotting. Overlapping CAS500-1 data were automatically processed with GCP (Ground Control Points) chips for better positional accuracy. Two test areas were selected including accessible and inaccessible areas.

Therefore, we conducted 1:5,000 large scale topographic mappings using CAS500-1 stereo data and assessed the accuracy. This prohibits the large scale topographic mapping from the satellite data.

However, the spatial resolution is relatively lower than that of aerial images. Using satellite data has a lot of advantages over aerial images in terms of repeatability, coverage, and accessibility. Having completed the calibration and validation processes, CAS500-1 has been acquiring land images to generate the basic geospatial information that are topographic maps, orthorectified images, and DEM (Digital Elevation Model). The mission of the satellite is the periodic monitoring of the land for efficient managements. A CAS500-1 (Compact Advanced Satellite) is a high-resolution Earth-observing satellite launched in Mar 2021 and being operated by National Land Satellite Center at NGII (National Geographic Information Institute).

Google satellite topographic maps