Application of Surveying Geographic Information in Emergency Surveying

In recent years, various types of emergencies have continued to increase, causing huge losses to the national economy. Emergency handling of all kinds of major emergencies requires the use of maps and geographic information provided by the surveying and mapping department as an important carrier and basis for understanding disaster conditions and scientific decision-making. In the process of emergency management, government agencies have a strong need for spatial information on the incident site. Today, the surveying and mapping technology is continuously developing from digitization to informationization. The surveying and mapping department has the ability and responsibility to provide real-time emergency surveying and mapping support for various departments. And services to meet the needs of emergency response and improve the pertinence and timeliness of government departments in handling emergency incidents.

The leaders of the Party and the State explicitly pointed out in the speeches of the academicians of the two academicians in 2008 that "we must speed up the application of remote sensing, geographic information systems, global positioning systems, and network communication technologies, as well as the transformation and comprehensive integration of high-tech achievements in disaster prevention and reduction, and establish The national comprehensive disaster mitigation and risk management information sharing platform will improve national and local disaster monitoring, early warning, assessment, and emergency aid and command systems."

In combating major natural disasters such as the Wenchuan earthquake, the strong earthquake in Yushu, mudslides in Zhouqu, and post-disaster reconstruction, the imagery of the disaster area acquired and produced by the surveying and mapping department is used in the emergency department to understand the disaster situation, command and decision making, rescue and relief, and reconstruction work. Play an irreplaceable role.

On June 1, 2015, the State Council approved the National Outline for the Civilian Plan for Surveying and Mapping (2015-2030), which for the first time clearly identified emergency mapping as one of the three major directions for the future development of geographic information for surveying and mapping. An important part of the incident emergency rescue system. In accordance with the requirements of the "Planning Outline," we must focus on summarizing the experience of emergency mapping service support in Sichuan and other regions. On this basis, strengthen the construction of emergency surveying and mapping equipment and emergency surveying and mapping information resources, establish and improve emergency surveying and mapping work mechanisms and inter-departmental emergency coordination and sharing mechanisms, strengthen information interconnection and interoperability, realize business networking coordination, and comprehensively improve emergency surveying and mapping service support capabilities.

I. Emergency Survey System Architecture

The technical system of emergency survey and support guarantee includes three main parts: data acquisition, data processing and information service.

Data acquisition: The use of space remote sensing, aerial remote sensing, and field data acquisition to obtain on-site data and transfer data back to the data processing center through a mobile monitoring vehicle.

Data processing: Using the integrated remote sensing image mapping system, emergency rapid mapping system and support of various professional mapping software, data fusion of multiple types, multiple sources, and multiple formats of emergency data is conducted to form the results of emergency surveying and mapping data.

Information service: Collect and process the existing data and emergency mapping data, and publish the geographic information service through the geographic information platform, and provide the emergency data to the emergency department at the first time.

In the event of an emergency, the departments responsible for the emergency task quickly carried out survey and mapping emergency security work according to the division of responsibilities, and started the mapping emergency response plan. Collect the existing surveying and mapping results and use the green channel to quickly provide maps to relevant emergency departments. At the same time, the surveying and responding team quickly assembled to the site to obtain the emergency data for surveying and mapping, processed and transmitted the data, and produced the emergency thematic map through rapid mapping technology, providing the emergency department with emergency thematic maps and mapping geographic information electronic map services. .

Second, key technologies for surveying and mapping emergency support

With the advancement of science and technology, modern surveying and mapping geographic information technology has achieved great development in terms of theoretical level, precision, application direction, etc., and greatly improved the level of emergency support for surveying and mapping. Key technologies for surveying and mapping emergency support include drone data acquisition, laser radar data acquisition, rapid processing of mapping emergency data, geographic information platform, and virtual reality technology.

(I) Rapid acquisition of integrated data in the sky

Through the mutual cooperation of advanced techniques of surveying and mapping and remote sensing technology such as oblique photography technology and laser radar, we have now achieved seamless integration of emergency surveying data acquisition in the sky.

1. Space remote sensing data collection. Space remote sensing mainly uses space shuttles or satellites for data acquisition.

The altitude of aerial photography aircraft is about 10 kilometers, and the satellite orbit of Landsat satellite is about 910 kilometers, so that a wide range of information can be obtained in time. Space remote sensing data collection has the following characteristics: First, it is fast and has a short cycle. Satellites can timely acquire the latest data of the regions in question and update the original data or perform dynamic monitoring according to the changes of old and new data. This is incomparable to artificial field measurements and aerial photogrammetry. The second is that data acquisition is limited by conditions. In places where the natural conditions such as deserts, marshes, and high mountains and mountains are extremely harsh, space remote sensing technology that is not limited by ground conditions can be used to obtain valuable information in a convenient and timely manner. And according to different tasks, the use of different bands on the object of different penetrating, but also access to the internal information. For example, the deeper ground, the lower layer of water, the water under the ice layer, the characteristics of the ground under the desert, etc., can work in the microwave band all-weather.

2. Aerial remote sensing data collection. Aerial remote sensing mainly uses low altitude data from drones or small aircraft.

Low-altitude remote sensing can realize real-time data transmission, acquire accurate remote sensing maps in a short period of time, understand site details at the first time, provide objective disaster data and decision support for disaster relief, and provide rich data sources for interpretation of ground disaster situations to assist in the analysis of disasters. Severity and its spatial distribution.

The low altitude aerial photography of the drone has the characteristics of flexible maneuverability, high efficiency, high speed, precision and accuracy, and has obvious advantages in high-resolution image acquisition in small areas and difficult-to-fly areas.

UAVs and small aircrafts are equipped with a tilting photography system. Using tilted camera measurements, they can obtain the texture information of the building surface from multiple angles, and can collect three-dimensional models of oblique photography. By using an airborne laser radar and an aerial camera, high-precision digital surface model data (DSM) and digital elevation model data (DEM) with image realism can be obtained.

3. Ground soldier system (as shown in Figure 2). The ground soldier system is mainly composed of a high-definition camera, a communication system, and a GPS positioning system. It can accurately obtain the location of the disaster (currently through the Tianjin satellite positioning service system, the positioning accuracy can reach 0.3 meters), and can transmit real-time video and location information to the command center through the communication system to provide more detailed field data for command decision making. On-site command and rescue.

4. Ground laser radar data acquisition. Ground laser scanning radar is divided into ground, vehicle, ship and hand-held types according to the platform. Ground-based laser radar is small and convenient, accurate and highly efficient, safe and stable, and has strong operability. It can collect point cloud data in the data acquisition area within minutes and establish detailed and accurate 3D stereoscopic images, which can provide accurate quantitative analysis. At the same time, the point cloud data collected by the low-altitude airborne laser radar and the point cloud data collected by the ground can be fused and merged to achieve seamless integration of point cloud data acquisition, thus providing more accurate and reliable data for the mapping emergency. stand by.

(II) Rapid processing technology for surveying and mapping emergency data

The raw data obtained during the surveying and mapping emergency must go through certain processing and processing, and be made into a map that can easily identify the application, so as to play an important role in the handling of emergencies.

The rapid processing of surveying and emergency data is based on the integration of remote sensing imagery mapping system, emergency rapid mapping system, and various specialized surveying and mapping software. It integrates emergency data of multiple types, multiple sources, and multiple formats to form emergency surveying and mapping. Data results.

1. Remote Sensing Image Integration Mapping System By using the photogrammetry technology to restore the position, shape, size and other information of the object from the sequence image, it can be quickly processed to obtain the empty three encryption results, panorama, point cloud, three-dimensional model and DEM/DOM. Wait for the data. The main process includes: orthorectification, image splicing, image fusion, color adjustment and so on.

2. Emergency rapid mapping system can be based on the use of existing data results, combined with the data collected in the emergency surveying and mapping, rapid extraction of key features in the data extraction data, after the edit and the existing data for data fusion processing Finally, emergency maps were obtained through quick annotation, symbolization, and map finishing.

(III) Geographic Information Platform Data Services

Take Tianjin's geographic public service platform as an example. The platform is the core construction content of the Digital Tianjin Geospatial Framework project that was jointly developed by the National Bureau of Surveying and Mapping and the People's Government of Tianjin, and it integrates multi-year, multi-category and multi-source geographic information resources. The rapid collection of field data in the emergency surveying and mapping, after processing, can quickly publish map services through the platform, and combine various geographic information data in the platform to truly reflect the scene of the incident and its surrounding conditions.

Through the linkage analysis and data mining of these multi-source, multi-topic, and multi-temporal data through the platform, more detailed and accurate decision support information can be obtained, facilitating the scientific deployment of rescue forces, formulating emergency plans, and assisting decision-making and commanding.

The data in the platform mainly includes: topographic map data, electronic map data, geographical entity data, multi-year aerial image data, place name address data, three-dimensional fine model data, and city street view data.

1. Topographic map data. Topographic map data is the most basic data of geographic information data, including the most comprehensive geographic information content, and is widely used in the design, construction, and other areas of planning and land use. In dealing with emergencies, you can use the topographic map to understand the detailed geographic information of the incident.

2. Electronic map data. Electronic map data content mainly includes information concerned by people, such as roads, points of interest, and important features, and is mainly used by some Internet and public display systems. In the emergency, information on the disaster can be distributed to the public through electronic map data.

3. Geographic entity data. Geographic entity data is effectively classified according to the nature of the ground features, including feature layers such as houses, roads, and water systems, and contains a large amount of management information, such as road names, house floors, etc., to facilitate analysis of incidents in emergency command. In the surrounding environment, make decisions and deploy.

4. Aerial image data. Multi-year aerial image data, which is widely applied to all walks of life in cities due to its intuitiveness and ease of use. Tianjin Geo-Public Service Platform contains data covering the entire region of Tianjin from the 1985 to the 13th edition of 2014, which can directly demonstrate the status quo of Tianjin's development and historical changes. Figure 3 reflects the changes in the cultural year 2008, 2010 and 2012. In the emergency command, the on-site aerial image data collected by the drone is loaded on the platform, which can intuitively show the scene of the incident.

5. Geographical name address data. Geographical name address data mainly includes water systems, land topography, administrative regions and other regions, residential sites, transport facilities with names, water conservancy, electric power, telecommunication facilities, memorials, tourist attractions, buildings, structures, and units. The degree can be detailed to the opening of each building. In dealing with emergencies, its main role is to locate and accurately locate the incident.

6. Three-dimensional fine model data. The three-dimensional fine model data includes data of buildings, various grounds, ground features, urban components, underground space, and integrated pipeline networks, and has high accuracy, scalability, queryability, and analysis capabilities. The use of three-dimensional data in emergency command and disposal can more intuitively reflect the spatial information of the event area and provide supportive decision support.

7. City Street Data. Urban streetscape data is a display of real city scenes. It is mainly generated through real picture production and has a strong sense of realism. The data can be viewed 360 degrees to see the field situation somewhere. The use of Street View data in responding to emergencies is more conducive to understanding the actual situation around the incident site.

(IV) Virtual Reality Emergency Applications

Virtual reality technology is also called Spiritual technology or artificial environment. It uses computer to simulate a virtual world in a three-dimensional space and provides user's visual, auditory, and tactile sense simulations. It can observe things in a three-dimensional space in a timely and unlimited way.

By combining the three-dimensional electronic maps produced by surveying data collection and mapping data fusion, virtual reality technology can be used for emergency scenario design as well as daily emergency drills and propaganda training. Virtual reality technology provides a brand-new development mode for emergency drills. It simulates accident scenes into virtual scenes, creates artificial accidents in virtual scenes, and organizes participating personnel to make correct responses. This kind of deduction has greatly reduced the input cost and has also played the role of drills and training.

The virtual reality system has the function of event simulation and analysis. In the emergency evacuation simulation, an evacuation route map may be generated according to the event conditions to simulate evacuation. In the flood analysis simulation, the submergence of urban floods can be simulated based on the amount of rainfall.

In emergency command, virtual reality technology integrates with other technologies to achieve more practical functions. For example, by integrating GPS and indoor positioning systems, rescue personnel's positioning information is displayed in virtual reality scenes, making it easier to formulate rescue programs and commands. Rescue; By integrating the video surveillance information in the Internet of Things, you can call and view real-time video information in a three-dimensional scene to further understand the actual situation on site.

Third, summary and outlook

The role of mapping and geographic information technology in emergency work is limitless. The progress and development of modern mapping geographic information technology in terms of theoretical level, precision, application direction, etc. have greatly increased the level of emergency support for surveying and mapping.

Future research focuses on data collection and data processing updates in emergencies; design of virtual reality emergency scenarios; use of cloud platform technologies to build emergency management information systems; and the combination of smart cities and emergency services, using IoT technologies to Integrate sensors (video, temperature, concentration, etc.), build smart emergency applications, and combine existing geographic information data with emergency command platforms through big data analysis technologies to provide more accurate and reliable decision support information for emergency management.

This article comes from "China Emergency Management", organized by the Chinese rescue equipment network , with deletions.