BEIJING: On July 17, a landslide hit Pengshui Miao and Tujia autonomous county in Chongqing.
Within an hour of the Ministry of Natural Resources activating a Level-II geological disaster prevention and emergency surveying response, Zhu Xiuli and her colleagues had produced the first batch of pre-disaster maps of the affected area.
Over the next two to three hours, they coordinated with Chongqing’s natural resources authorities to obtain post-disaster drone imagery and produced a second batch of maps integrating the scenes before and after.
The images were delivered to the emergency rescue command center, where they served as base maps for the unified dispatch of rescue, engineering, and geological survey and monitoring teams.
Two decades ago, producing a similar map would have taken one or two days, with all data processed and formatted manually. Today, powered by rapidly acquired drone imagery, preloaded base geographic datasets and embedded cartographic rule libraries, the same work can be completed in dozens of minutes.
Zhu, a technician with the National Geomatics Center of China at the Ministry of Natural Resources, has witnessed the transformation firsthand.
She has worked in cartography and geographic information for more than 20 years and has participated in more than 100 emergency mapping responses, including the 2010 Yushu earthquake in Qinghai province, the 2010 Zhugqu debris flow in Gansu province, the 2022 Luding earthquake in Sichuan province and, most recently, the Pengshui landslide. She has produced more than 1,000 thematic emergency maps.
The emergency surveying process begins the moment a disaster is reported. For earthquakes, the China Earthquake Networks Center publishes the geographic coordinates of the epicenter, and the team receives an alert with the precise location by text message. For other events, the team cross-references news reports with administrative place names to pinpoint the disaster site — a step Zhu said “takes some time”.
Once the location is confirmed, her team pulls base geographic maps covering a 10-to-50-kilometer radius, including administrative boundaries, road networks, waterways and pre-disaster satellite imagery.
Once the disaster point is marked, the first map of the affected area is produced.
“From that map, the entire situation around the affected area is clear at a glance, facilitating emergency response coordination,” Zhu said.
Rapid acquisition of post-disaster imagery provides an irreplaceable “ground truth” for precise assessment, according to Zhu. Under the national-local coordination system for emergency surveying and mapping support, local natural resources departments dispatch drones to affected areas to capture post-disaster imagery, transmitting data to on-site experts, relevant departments and the national-level emergency mapping team.
Post-disaster drone imagery enables detailed before-and-after comparisons. Zhu said that during the Pengshui response, comparative maps integrating pre- and post-event imagery, collapsed boundaries and affected buildings provided direct, accurate data support for deploying rescue forces and assessing the disaster.
“You can actually count how many houses collapsed,” she added.
Zhu highlighted the importance of timeliness in her work, noting that rule-based template libraries — encoding cartographic conventions for road hierarchy, waterway classification and settlement importance — are now embedded directly into mapping systems. This eliminates the manual application of design standards that once slowed production.
Artificial intelligence is also beginning to enter the field, particularly in automated change detection between pre- and post-disaster images.
“AI will definitely empower the digital and intelligent transformation of surveying and geographic information,” she added.
Although her work remains largely invisible to the public, Zhu knows its absence would be felt everywhere.
“Surveying and geographic data are not just maps on a screen. They are the invisible nervous system of the information age — powering everything from emergency rescue to everyday navigation, from urban planning to national resource security,” Zhu said.
“We are building the foundational layer for the information age,” she said. “That’s not something you walk away from.” –The Daily Mail-China Daily news exchange item
