CHINA has unveiled its first national geometric reference imagery — a high-precision spatial template covering the entire country at a 0.5-meter resolution. The template ensures that satellite imagery produced by different agencies across the nation aligns with the same exact coordinates, creating a unified remote sensing base map.

Though invisible to most map users, geometric reference imagery underpins virtually all satellite-derived spatial data. When raw images are transformed into usable map products, they must undergo georeferencing — assigning precise geographic coordinates. This new template acts as a calibration master, much like a mold in traditional woodblock printing, ensuring that images from various sources and batches register to identical positions.

“This is the first national geometric reference imagery covering all of China’s land territory,” said Yu Dequan, deputy director of the land satellite remote sensing application center at the Ministry of Natural Resources. He called it a milestone for building a digital China and upgrading the surveying and mapping industry, as well as a new public service product for society.

Yu highlighted that the template achieves a spatial resolution of 0.5 meters nationwide, using both national and local high-resolution imagery. Positioning accuracy has also been significantly improved, with technical challenges in mountainous, plateau, and uninhabited areas overcome. This has doubled overall positioning accuracy nationwide and resolved long-standing geometric accuracy issues in western China’s orthophotos.

Beyond improving accuracy, the template enhances data production efficiency, enables better automation matching, and reduces costs for enterprises and organizations producing high-resolution remote sensing imagery, Yu added.

Chen Jun, director-general of the ministry’s land surveying and mapping department, noted that this release is only the first step. The ministry plans to follow with a nationally unified radiometric reference imagery, which will standardize brightness and color values across different sensors and time periods, enabling more reliable data comparisons.

The release aligns with the ministry’s broader modernization agenda for the 15th Five-Year Plan period, which includes building a next-generation millimeter-level national coordinate framework, completing the real-scene three-dimensional China initiative, and deepening integration of public and commercial satellite resources for coordinated remote sensing coverage.(SD-Agencies)