Natl spatial template to ensure unified satellite imagery

China released its first national geometric reference imagery on Thursday, a high-precision spatial template covering the entire landmass at a 0.5-meter resolution. This template is designed to ensure that satellite imagery produced by different organizations across the country aligns with the same exact coordinates.

The product, jointly developed by the Ministry of Natural Resources and provincial natural resources authorities, was unveiled in Beijing ahead of the 23rd National Surveying and Mapping Law Publicity Day, which fell on Saturday this year.

Geometric reference imagery serves a function that most map users will never see but underpins virtually all satellite-derived spatial data. When raw satellite imagery is transformed into usable map products, it must undergo georeferencing, which involves assigning precise geographic coordinates. The geometric reference imagery acts as a calibration template for that process.

"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 of the Ministry of Natural Resources.

"It represents a significant milestone in supporting the construction of a digital China and promoting the transformation and upgrading of the surveying and mapping geographic information industry. It is also a new type of public product for surveying and mapping geographic information services to society," Yu said.

Yu compared the product to the mold in traditional woodblock printing — a master template that ensures imagery from different sources and different batches all register to the same exact positions, forming a nationally unified satellite remote sensing base map with nationally unified precision.

This advancement enhances data production efficiency, facilitates better automation matching, and significantly reduces the cost of producing high-resolution remote sensing imagery for enterprises and organizations, he added.

Yu highlighted that the spatial resolution is remarkably high, with both national and local high-resolution imagery utilized in production, achieving an overall national spatial resolution of 0.5 meters.

Additionally, the positioning accuracy has been significantly improved, overcoming technical challenges in maintaining accuracy in mountainous, plateau, sparsely controlled, and uninhabited areas. This advancement has doubled the overall positioning accuracy of remote sensing imagery nationwide and addressed long-standing issues with the geometric accuracy of orthophotos in western China, Yu said.

He added that the ministry will continue to promote the application and dynamic updating of the geometric reference imagery.

Chen Jun, director-general of the ministry's land surveying and mapping department, noted that the completion of the national geometric reference imagery is the first step in a broader push to standardize remote sensing data across China.

The ministry plans to follow up with the construction of a nationally unified radiometric reference imagery, which standardizes not just position but also the brightness and color values of imagery, enabling more reliable comparison of data captured at different times and by different sensors, Chen added.

The release comes as the ministry accelerates its broader surveying and mapping modernization agenda for the 15th Five-Year Plan period (2026-30). These include building a next-generation millimeter-level national coordinate framework, completing the real-scene three-dimensional China initiative, and deepening the integration of public and commercial satellite resources for coordinated remote sensing coverage.