Introduction to Surveying and Mapping Science

Geodesy: a basic subject in the field of surveying and mapping and earth science.

(A) modern surveying and mapping benchmark system

Modern surveying and mapping datum system provides the starting point of spatial position, elevation and gravity for the acquisition of geospatial information. It consists of the corresponding reference system and its corresponding reference system. Geodetic reference frame and geodetic reference frame are the basis of calculating spatial position. Almost all developed countries in the world are adopting International Terrestrial Reference Frame (ITRS) and International Terrestrial Reference Frame (ITRF). In recent ten years, China has also built the 2000 National GPS Geodetic Control Network by using space observation technology, and completed the joint adjustment of this network and the National Astronomical Geodetic Network, so that the 2000 National Geodetic Coordinate System (CGCS2000) not only has a clear definition, but also has a high-precision reference frame.

The elevation datum in China is 1985 height system in the Yellow Sea, and the datum is Qingdao leveling origin and its elevation value. Its frame of reference is the national first-class and second-class leveling network. Another form of elevation datum is elevation starting surface (positive height or normal height), and CQG2000 quasi-geoid is adopted in China. As for the gravity datum, there are the Potsdam gravity system and the international gravity standard network (IGSN7 1) in the world. At present, China adopts the 2000 National Gravity Basic Network as the gravity benchmark.

(2) Satellite navigation and positioning technology

GPS System The United States has formulated a "GPS Modernization Plan" by 2020. Its essence can be summarized as the following three aspects, namely, the "3P" policy: first, protection; The second is prevention; The third is preservation. The European Space Agency (ESA) has finalized the space configuration including 30 Galileo satellites, and the most effective scheme for the layout of the corresponding ground control stations. At the same time, the relationship between Galileo and the external system is determined. It is expected that the system will be put into operation after 20 10. At present, Russia is maintaining and updating the GLONASS system, and has made a master plan to develop a new generation of GLONASS-M satellites, so as to increase the satellite life and improve the satellite performance, and make the number of constellation satellites reach 24. China is developing the Beidou second-generation satellite navigation and positioning system, and the satellite constellation design takes into account the transition to the global navigation and positioning system.

The progress of GPS positioning methods is mainly reflected in the following aspects: First, the precise point positioning technology can use the precise ephemeris of GPS satellites predicted by IGS or the precise ephemeris afterwards as the initial data of known coordinates. At the same time, the precise satellite clock error obtained in a certain way replaces the satellite clock error parameter in the user's GPS positioning observation equation, so that the user can use the observation data of a single GPS dual-frequency dual-code receiver to make real-time dynamic positioning at any position in thousands of square kilometers or even in the global scope, or make fast static positioning with an accuracy of 2 ~ 4 cm. The second is network RTK, which is a method to establish a plurality of GPS reference stations with known coordinates in a large area to form a mesh coverage of the area, and to correct the positioning of satellite positioning users in the area in real time based on the error correction information of phase observations calculated and broadcast by these reference stations. Some developed countries abroad and China have established regional continuous operation satellite positioning service system by using network RTK technology. Satellite navigation and positioning based on multi-frequency combination and multi-satellite system fusion has become a research hotspot in the field of international satellite navigation and positioning.

(3) Theoretical research on the gravity field and geoid refinement.

Determining the gravity field model of the earth can be solved by using the observed gravity anomalies known on the ground. At present, satellite gravity method is mostly used to establish the earth gravity field model. One is the perturbation of the observation satellite orbit to the reference (normal) orbit, which can be the perturbation of the ground observation satellite orbit or the perturbation of the high-orbit satellite (such as GPS satellite) to the low-orbit satellite (such as CHAMP satellite), and then the potential coefficient is solved according to the satellite orbit perturbation theory and its observation data; Secondly, using the mutual tracking of two satellites in the same low orbit (such as GRACE satellite), the change of inter-satellite distance is measured and the potential coefficient of the earth's gravity field is inverted. Thirdly, a gravity gradiometer (such as GOCE satellite) is installed on the LEO satellite to directly measure the gravity gradient in the satellite orbit, thus solving the potential coefficient.

Determining the geoid is generally to calculate the relative geoid suitable for a certain region or country. At present, the most commonly used and best method to solve the gravity geoid at home and abroad is the removal-restoration technology. In addition, the geoid gap can be directly observed by GPS geoheight and precise leveling. In order to obtain high-precision and high-resolution geoid finally, high-resolution gravity geoid can be fitted to the geoid obtained by high-precision GPS leveling. In recent years, China has established high-precision and high-resolution quasi-geoid in China and many provinces and cities. The accuracy of quasi-geoid in some cities can reach centimeter level, and the resolution can reach 2' 30 ″× 2' 30 ″.

(4) crustal movement monitoring and geodesy geodynamics

With the continuous development of space geodesy observation means, the expansion of the observable coverage of the surface and the improvement of accuracy, the research object has expanded from local (such as faults) to regional (such as plates) and even the whole world. At present, China's crustal movement monitoring and geodesy geodynamics research have mainly achieved the following practical results. The velocity field, deformation field and horizontal strain rate field of present crustal movement in Chinese mainland are obtained. A two-dimensional finite element model of Chinese mainland is established. The absolute and relative plate motion parameters of five main plates are solved. The measured plate motion model GVMI is obtained. In addition, the crustal movement of Ordos block, Qinghai-Tibet Plateau, Sichuan-Yunnan region, North China and other parts of China, as well as the west Kunlun Mountain Pass earthquake with M = 8. 1 were also studied.

Photogrammetry and Remote Sensing: Modern Image Information Subject Based on Computer

(a) Digital photogrammetry technology

1. A new generation of digital photogrammetry processing platform

China is setting up a new generation of data processing platform for space digital photogrammetry, and the blade cluster processing system has appeared. It consists of a high-performance blade computer system, a disk array and a standby power supply. It is an automatic data processing system based on the latest image matching theory and practice, which breaks the traditional photogrammetry process, integrates production, quality inspection and management, and can further improve the production efficiency of digital photogrammetry.

2. Photogrammetry based on DGPS/IMU integrated navigation technology and lidar scanning technology.

Using the integrated navigation system composed of differential GPS and IMU loaded on the aircraft, the external orientation elements of the camera and the absolute position of the aircraft can be obtained, and fixed-point photography and imaging and high-precision direct positioning on the ground can be realized without ground control. Airborne lidar (Light Detection and Ranging) is a kind of earth observation system integrating laser, global positioning system and inertial navigation system, which can directly obtain high-precision three-dimensional information of the real surface. China focuses on the research and application of surface information acquisition, data processing and integration with remote sensing images.

3. Application technology of aerial digital camera

The biggest advantage of digital camera is that it can greatly improve the accuracy and reliability of image matching and three-dimensional reconstruction (or stereo mapping) without increasing the image acquisition ability of flying cost (for example, more than 80%), and make real orthophoto images. In China, we independently developed a large format digital camera.

4. Digital photogrammetry technology in digital city modeling.

Obtaining the real three-dimensional model of urban houses from large-scale aerial images is one of the effective ways to realize the three-dimensional modeling of cities. At present, the low-altitude flying platform is used as the sensor carrier, and the digital camera is installed on the rotatable platform to shoot images of urban areas in multiple air bands, and then the images taken by ground-mounted or handheld digital cameras are processed as a whole to generate products such as building facade image mosaic, which meets the needs of digital cities and three-dimensional scene visualization.

5. Satellite image positioning technology with little or no ground control.

Digital photogrammetry technology and methods have been widely used in geometric processing of high spatial resolution satellite images, and a lot of research focuses on how to improve the plane and elevation accuracy of images with few or no control points. Up to now, there are still 2 million square kilometers of land in western China without1:50,000 topographic map. China will adopt the comprehensive means of modern geo-spatial information technology, such as space remote sensing, digital aerial photography, space synthetic aperture radar, satellite navigation and positioning, geographic information system, mapping without control points or with few control points, to implement the western mapping project.

(2) Spatial remote sensing mapping technology

1. Acquisition of space remote sensing data

At present, China has initially formed five series of remote sensing satellites-recoverable remote sensing satellite series, "Fengyun" meteorological satellite series, ocean satellite series, earth resources satellite series and environment and disaster monitoring small satellite group series, and has begun to form a long-term and stable satellite observation system to realize three-dimensional observation and dynamic monitoring of China and its surrounding areas and even the global land, atmosphere and ocean.

2. Remote sensing image information extraction and multi-source remote sensing image fusion technology.

Using hyperspectral images to automatically detect and identify targets is an active research topic in the field of remote sensing information processing. For example, in a complex unknown background, because the spectral response of the artificial target is different from the background and its size is relatively small, it can be regarded as an abnormal target. How to detect such targets from hyperspectral images without sufficient prior knowledge has been studied in China.

Any information from a single remote sensor can only reflect one or several aspects of the characteristics of ground objects. On the one hand, data fusion technology can remove useless information, reduce data processing and improve efficiency; On the other hand, useful information can be collected from massive multi-source data and fused together, which facilitates the complementary characteristics of various information and reduces the ambiguity and uncertainty of identifying targets.

3. Integrated processing of remote sensing image and GIS.

Geographic Information System (GIS) is a system for analyzing and displaying spatial data. Remote sensing image is a form of spatial data, similar to raster data in GIS. Therefore, it is easy to realize the integration of GIS and remote sensing at the data level, which has been realized in software at present.

4. Research on the theory and application of remote sensing data processing.

In terms of basic research, China has carried out basic research in the fields of target radiation characteristics, atmospheric propagation model, inversion method and radiation calibration, remote sensing data processing in INSAR and D-INSAR methods, spatial reasoning in remote sensing, expert system and data mining, and multi-source remote sensing data fusion.

In the application research of remote sensing, China has developed some new remote sensing data processing methods and systems in daily weather, ocean, environmental forecasting and disaster monitoring, resource investigation, land use, urban planning, crop yield estimation, national census, desertification monitoring, environmental protection, climate change and national defense.

Cartography and geographic information engineering: the subject of transmitting spatial geographic environment information in graphic and digital form.

(1) Making computer digital maps.

The production of cartography has realized the leap-forward development from traditional manual cartography technology to modern computer digital cartography technology. Digitalization and integration of drawing and publishing have become the basic technical means of drawing production in China, which has completely changed the backward situation of drawing technology and enhanced the scientific nature of drawing and publishing.

(b) Diversified forms of geographic information services

The number of GIS software in China increased from 565,438+0 in 2004 to 66 in 2005. The types of GIS products have developed from comprehensive GIS basic platform software at first to basic platform software, application development platform software, special tool software, application software and so on. Various map visualization systems such as electronic map, multimedia electronic map, network electronic map and mobile device navigation electronic map are constantly emerging, and the user range is more popular.

(3) Comprehensive research on automatic map drawing.

China has made outstanding achievements in solving many problems of automatic synthesis, which fully embodies the spirit of independent innovation, creates very favorable conditions for electronic computers to simulate people's thinking mode according to models in the process of drawing synthesis, and objectively and correctly reflects the thinking characteristics of human brains. Although it is impossible for computer to completely simulate the thinking process of human brain in the process of cartographic synthesis, it can approach this goal to the maximum extent.

(d) Uncertainty of spatial data and data quality control

This paper mainly discusses and studies the causes and manifestations of GIS spatial data uncertainty, the processing methods of GIS spatial data uncertainty, and the propagation mechanism of GIS spatial data uncertainty in the process of analysis and processing. For example, the data quality information service system based on Web Service, digital elevation model (DEM) uncertainty and other achievements have important theoretical and practical significance for deepening the study of GIS spatial data uncertainty.

(v) Practicality of virtual reality technology

For virtual geographic environment, we now pay attention to the research and construction of a unified distributed virtual geographic environment system framework, with the aim of realizing the interoperability between different types of simulation systems and the reuse of components, which embodies the characteristics of hierarchy, abstract data types, implicit activation and support for distribution. Through the in-depth study of scene modeling and control in virtual reality technology, the system is truly distributed, three-dimensional, interactive, multimedia integrated, realistic and closer to practical use.

(vi) Spatial data mining and knowledge discovery research

In recent years, the research on spatial data mining and knowledge discovery has made remarkable progress. In its algorithm research, for example, a spatial outlier detection algorithm is given in view of ignoring a small number of new data patterns which are significantly different from the conventional data patterns in GIS database.

(vii) Geospatial information grid technology

Spatial information grid is put forward in the field of geo-spatial information science or surveying and mapping science and technology, which is essentially the fusion and integration of grid technology and spatial information technology. In China, it is studied in both broad and narrow sense.

(8) Cartography and geographic information engineering theory.

In addition to traditional theories such as map projection, map synthesis and map symbols, modern theories such as map spatial cognition theory, geographic information transmission theory and map visual perception theory have been added to the disciplines such as map cartography and geographic information engineering, and the theoretical system of map cartography and geographic information engineering science is gradually taking shape.

Engineering surveying: the applied discipline of surveying and mapping science and technology in national economic and social development

(A) the new technology of precision large-scale engineering survey

Satellite positioning technology has been widely used in various engineering control networks. Especially with the development of geoid refinement, the engineering control network has developed from two-dimensional to three-dimensional, which has completely changed the defects of traditional engineering control network. High-precision real-time RTK technology is used for construction lofting in precision large-scale engineering survey. Combined with the engineering characteristics, some special instruments and tools are designed and manufactured, so that various disciplines and technologies can be infiltrated and integrated in construction survey and applied to construction survey. GPS and GIS technologies will be closely integrated with engineering projects and play an important role in the integration of survey, design and construction management.

(b) Digital City and Industrial Information System

At present, the city's large-scale topographic map, cadastral map, real estate map, completion map, underground pipe network map, navigation electronic map, etc. Digital mapping is basically realized, and various types of digital mapping systems are constantly emerging. The interface between these mapping systems and common geographic information systems realizes the exchange of field collection data and GIS data, making the field digital mapping system a subsystem of front-end data collection of GIS system. Now both urban planning and architectural design are carrying out three-dimensional planning and three-dimensional design; The real estate industry promotes three-dimensional housing sales online; Navigation electronic map and three-dimensional navigation map. All these put forward the requirements for mapping the three-dimensional status map. Make full use of digital mapping technology, develop an integrated data acquisition and mapping system for indoor and outdoor work, and provide high-quality and multi-form spatial basic information support for engineering survey, design, construction and completion archiving of large-scale engineering construction.

Cities above the provincial capital and some prefecture-level cities have established urban basic geographic information systems. The modern management of municipal facilities is becoming more and more important. At present, both at home and abroad attach great importance to the research of spatial information grid technology in the modern management of municipal facilities, manage municipal facilities information according to grid database, and monitor dynamic changes.

(3) Deformation monitoring technology

Deformation monitoring is a necessary measure to ensure the safety of equipment and personnel during the construction and use of buildings. At present, super-large buildings, structures, basements and other projects appear constantly, and the accuracy of deformation monitoring is also very high, generally around 1mm, and some require sub-millimeter level. In data processing, a mathematical model reflecting the deformation amount and deformation factor should be established according to the actual situation, the causes of deformation should be analyzed, and the deformation trend should be predicted if necessary. Modern deformation monitoring often combines modern geodetic instruments with space technology, laser technology and wireless communication technology to realize continuous, dynamic, real-time and automatic monitoring, and has the functions of automatic aiming, automatic observation, automatic recording, automatic data processing and automatic generation of various graphs and reports.

(d) industrial measurement technology

Modern industrial production requires rapid and high-precision measurement and positioning of product design, simulation, production automation process, production process control, product quality inspection and monitoring, and gives complex digital models or running trajectories. Therefore, measurement technology serving industrial production came into being. Its means and equipment are mainly electronic theodolite or total station, camera or micrograph, laser scanner and other sensors in the computer software and hardware support to form a three-dimensional measurement system. The introduction of these technologies has greatly improved the automation level of precision measurement in industrial field.

(5) Detection technology of urban underground pipelines

The detection, detection and evaluation technology of underground pipelines provides a fast, economical and effective means for finding out the present situation of existing underground pipelines in cities and evaluating the risks of underground pipelines. Ground penetrating radar (GPR) in nonmetallic pipeline detection technology makes up for the defects of conventional underground pipeline detectors and becomes one of the important technical means to detect nonmetallic underground pipelines. The use of electronic marker provides a new method for the detection of nonmetallic underground pipelines. The construction of urban underground pipeline information management system has gradually developed from the original isolated system construction mode to fully integrate the existing urban underground pipeline information resources and establish an urban underground pipeline information sharing platform.

Marine Surveying and Mapping: Science and Technology of Marine Spatial Surveying and Mapping

(1) Hydrological survey

In the process of ocean exploration, in order to solve the problem that the beam angle effect of echo sounder distorts the recorded detection image, an improved beam angle effect model and its correction algorithm are proposed. Aiming at the multi-beam bathymetric data set, an improved inverse distance weighting algorithm and multi-level-of-detail model technology are used to establish a digital seabed terrain model (DTM). Using dual-frequency GPS dynamic post-processing high-precision positioning technology, a complete set of GPS tidal-free ocean sounding operation mode is established, which significantly improves the accuracy of sounding results.

(2) Measurement of marine gravity field and magnetic field

With regard to the determination of marine gravity, firstly, the problem of establishing a new generation of digital model of average gravity anomaly on land and sea in China is studied: based on the spectral theory of gravity field, the power spectrum expression of disturbed gravity in the sense of global average is given; The conversion formula of partial derivative between vertical deviation and geoid difference is derived. The series solution of horizontal gravity gradient boundary value problem is derived.

In the study of marine magnetic survey, a simple formula for calculating the distance between survey lines is derived from the magnetic field of magnetic dipole. According to the definition of magnetic field lines and the distribution of magnetic field around a uniformly magnetized sphere, a simple formula of magnetic field line clusters is derived. Based on terrestrial geomagnetic diurnal variation station, a real-time data acquisition and transmission system is designed and developed by combining DGPS system and buoy technology. The technical method of laying anchor system for geomagnetic diurnal variation observation on the seabed is adopted to solve the correction problem of geomagnetic diurnal variation observation data in far sea area.

(3) Space-based ocean mapping technology

Firstly, the method of single-chip positioning of high-resolution satellite CCD images using rational function model is studied emphatically. Secondly, a semi-automatic building extraction method from remote sensing images is proposed. Thirdly, a sub-pixel target recognition method for hyperspectral remote sensing images based on multi-resolution wavelet high-frequency feature coefficients is proposed. Fourthly, aiming at the inadaptability of IKONOS high-resolution satellite image processing, a more accurate and detailed image fusion method-adaptive wavelet packet analysis method is proposed. Fifthly, based on the flight orbit law of altimetry satellites, a new method for calculating the sea level at normal points by "distance weighted average" is proposed. Sixth, the influence of the selection of observation satellites on the quality of baseline calculation is studied, and the baseline processing method of artificially selecting satellites to improve the quality of baseline calculation is put forward.

(4) nautical charting and marine geographic information engineering

Firstly, a new map synthesis algorithm based on circle principle and the idea of "survival of the fittest" is proposed. Secondly, the coordinate transformation method in digital mapping is discussed, and a set of operating ideas and methods are summarized. Thirdly, the solution and realization process of making multimedia electronic map based on Flash technology are put forward. Fourthly, the incremental construction method of Delaunay triangulation automatically generated by computer is studied. Fifthly, the display and browsing of MapInfo graphic data in IE are realized, and the feasibility of visualizing geospatial data with VML is verified. Sixthly, a computer drawing system is established.