Nowadays, high and new technologies such as remote sensing, geographic information system, global positioning system and information network have become a new information industry, which is rapidly infiltrating into various disciplines, national economy and people's lives, and promoting the development of science and technology and society to a higher level.

Several Concepts of 1

1. 1 remote sensing

Physical characteristics of remote sensing or remote detection targets. "Far" has the concept of space, that is, near-earth space, outer space and even cosmic space. "Feeling" refers to information systems, including information acquisition and transmission, information processing and extraction, information analysis and visualization systems. The so-called goal is the object to be observed. As far as geoscience is concerned, there are surface objects, geological bodies, geological events and so on. About the physical characteristics of the target, it mainly refers to the characteristics of the object to electromagnetic radiation. People use the difference of spectral characteristics of ground objects to identify them, so the spectral characteristics of ground objects have become an important theoretical basis of remote sensing geoscience.

Remote sensing image processing system: a system that processes, analyzes, synthesizes and visualizes remote sensing images by means of optical instruments and computer equipment. At present, computer remote sensing digital image processing system is commonly used.

1.2 geographic information system

With the support of computer, collect, store, manage, analyze, synthesize and describe geospatial information systems related to geographical distribution.

1.3 remote sensing geographic information system (RS-GIS)

It refers to the integration of remote sensing image processing system and geographic information system.

1.4 global positioning system

A system for global navigation and positioning through multiple satellites.

2 development overview

2. 1 A new information industry is emerging.

Remote sensing, geographic information system, global positioning system and information network are high and new technologies developed in recent decades. Because of its advanced nature and practicality, it has transformed from a new technology into a new industry in a short time, forming its own products, output value and market, which has produced great economic and social benefits. The rise of industry, in turn, accelerated their development and mutual integration, formed new disciplines and technical methods, and penetrated into other disciplines and social and economic departments.

2. 1. 1 remote sensing

Aerospace remote sensing enables people to quickly and accurately obtain all kinds of information from large geographical areas to the whole world, such as weather forecast, resource distribution, disaster monitoring, environmental pollution and so on. So countries are competing to develop remote sensing.

Space Remote Sensing: Since the Soviet Union launched the first artificial earth satellite on June 4th, 1957, all countries have carried out space remote sensing with great enthusiasm and huge economic budget, especially the United States, which has shown the world with great speed and amazing achievements. In the 1960s and 1970s, the United States successively launched meteorological satellites and resource satellites, opened up space shuttles and Earth space stations, and launched multiple probes into space to detect planets and celestial bodies such as the moon, Mars and Jupiter. France, Russia, Canada, Japan, India and other countries have also launched corresponding resource satellites. China has its own meteorological satellite and resource satellite, which has achieved manned space flight and made plans to explore the moon and planets of the solar system. The ground resolution of remote sensing detection has reached the meter (m) level, and the spectral resolution has reached the nanometer (nm) level, and the repetition period is several days to several hours. The application of remote sensing technology in science and economy is more and more common, and the application effect is very remarkable. Many departments have incorporated remote sensing technology into production norms. Scientific research departments and colleges have set up corresponding majors and are training remote sensing technical talents in batches. The state and government departments have corresponding remote sensing centers and sites, which are specialized in the acquisition, distribution and use of remote sensing data. All these have formed the remote sensing information industry in developed countries and China, and have considerable output value and rapid development prospects.

Aerial remote sensing: In a certain geographical range, it has become very common to obtain remote sensing images by aircraft. As far as China is concerned, some large and medium-sized cities and some economically developed coastal areas have obtained multi-period remote sensing images for urban planning and urban development monitoring, such as Beijing, Shanghai, Tianjin, Wuhan, Xi, Shenyang, Bohai Bay, Yangtze River Delta, Yangtze River Basin, Pearl River Delta and other cities and regions.

With the processing, enhancement, analysis and comprehensive processing of the image processing system, the quality of remote sensing images has been greatly improved, and various thematic information satisfying users' requirements has been extracted. Image processing software emerges one after another, with more and more powerful functions. With the rapid development of computers, image processing hardware has formed large, medium and small processing systems to meet the various needs of countries, regions and individuals, especially microcomputer processing systems.

To sum up, we can see that the rapid development of remote sensing technology is inseparable from the rapid development of space technology and computer technology. In addition, the innovation of remote sensing technology and theory plays a very important role in the following aspects: sensors-cameras, scanners, temperature radiometers, microwave radiometers, fluorescence radiometers and so on. Band-near ultraviolet, visible light, near infrared, middle infrared, far infrared, microwave, etc. Repetition cycle-from the early dozens of days to the present days to several hours; Resolution-spatial resolution ranges from tens of meters to centimeters, and spectral resolution ranges from micron (micron) to nanometer (nm); Image processing methods-from general enhancement and information extraction to human-computer interaction and semi-automatic recognition; Spectral information-from the measured spectrum of ground objects to direct extraction from images or spectral reconstruction; Multi-scale-image fusion from a single scale to many different scales; Multi-data sources-from a few data sources to a variety of platform data sources, remote sensing information and other information together for multi-information synthesis; Theoretical broadening-the theoretical basis of image processing has been broadened from the initial probability and statistics theory to nonlinear theory, artificial intelligence and other fields. Therefore, multi-band, multi-phase, multi-scale, multi-data, high precision and rapidity have formed many characteristics of remote sensing technology. Coupled with image processing technology and information extraction means, the application field of remote sensing has become wider and wider, and it is irreplaceable in some industries.

2. 1.2 Geographic Information System

In 1950s, the function of Land Information System (LIS), which just sprouted in Europe, was very simple. In 1970s, with the rapid development of computers, practical GIS appeared in the United States, Canada, Germany, France, Sweden, Japan and Australia. In 1980s, geographic information system has entered the stage of popularization and application, and all countries in the world have made breakthroughs in the development of basic geographic information system software and application software. Representative softwares such as ARCINFOR and MAPGIS have become necessary tools for relevant departments in land use management, urban planning, population planning, resource management, traffic management and safety management. With the in-depth development of GIS and the popularization of digital products in 1990s, digital city, digital life and digital earth times have arrived. With the combination of GIS and other disciplines, the industrialization of geographic information is inevitable (standardization, information sharing, computer software and hardware resources sharing, etc.). ).

2. 1.3 Global Positioning System (GPS)

The satellite navigation and positioning system serving military purposes has been opened to the whole world, and people can quickly obtain the corresponding geographical coordinates anywhere on the earth with a small positioning receiver. The United States has developed into the third generation positioning system, the European Union is also establishing its own Galileo plan, and China also has its own positioning system (Samsung) to cooperate with the Galileo plan.

2. 1.4 information network

From 1970s to 1980s, in order to enjoy information and computer software and hardware resources, people developed computer networks and local area networks (such as a unit or a local area network). As soon as these networks appeared, they showed great advantages. People can sit in front of their own terminals, call the information of others and other departments, and enjoy the resources in other people's computers. From 1980s to 1990s, people can quickly obtain relevant information through cross-regional, cross-border and even international communication networks, and enter thousands of households through the network. With the popularity of wireless communication, people can access the network anytime and anywhere, and the network has become an indispensable thing in people's lives. Although the network will have various negative effects, its development trend will not decrease.

The above-mentioned scientific and technological progress and industrialization tell us that remote sensing and global positioning system can quickly obtain the information of the target and use geographic information system as the carrier to flow quickly on the international network. The "information superhighway" has been opened, the information revolution is happening around us, and the digital earth times is coming.

2.2 People's way of thinking and behavior is changing.

2.2. 1 From macro to micro, from the whole to the local way of thinking.

The emergence of remote sensing makes it possible for people to understand many problems from a large geographical scope to a global perspective, from a macro and holistic perspective, so that things that some people can't understand can be obtained from the whole, making people's way of thinking more comprehensive and complete, making the relationship between the whole and the part of things concrete and clear, and avoiding the one-sided way of thinking of "I don't know the true face of Lushan Mountain, I am only in this mountain".

2.2.2 Brand-new technical route and working method.

Remote sensing image processing can not only improve image quality, enhance and extract information, but also provide the technical prospect of information synthesis, semi-automatic image recognition and automatic drawing.

Geographic information system provides the storage, analysis and mapping functions of spatial information, realizes the automation of geographic information system mapping, and greatly reduces people's labor force.

Network enables people to enjoy the information and computer resources owned by society, and accelerates the dissemination of information. It can really be said that "a scholar does not go out and knows what's going on in the world."

2.2.3 New discipline systems and institutions have emerged.

The disciplines based on remote sensing include: remote sensing geology, environmental remote sensing, agricultural remote sensing, urban remote sensing, resource remote sensing and so on. Many remote sensing institutions have been established: resource satellite launching institutions, ground satellite data receiving stations, remote sensing application research departments and remote sensing discipline professional and training centers.

Based on geographic information, there are: geographic informatics, information engineering and so on. Geographical information centers, sites, laboratories of remote sensing information system for resources and environment and academic groups have been established.

2.2.4 Government's decision-making behavior

Western governments are taking measures to accelerate the development of remote sensing and promote the further industrialization, standardization and internationalization of geographic information systems. China government also attaches great importance to this, and relevant departments are taking measures to accelerate the development of remote sensing and geographic information system.

3 New progress and development trend

3. 1 New progress and trend of remote sensing technology

3. 1. 1 There are three new technologies and trends (multi-platform, multi-sensor and multi-angle) and three highs (high spatial resolution, high spectral resolution and high time-phase resolution) in remote sensing data acquisition.

Multi-platform-such as low, medium and high orbit satellites, large, medium, small and micro satellites, etc.

Multisensor-Similar to a platform with cameras, scanners, thermal imagers, imagers with different spatial resolutions, etc.

Multi-angle-such as vertical and horizontal multi-angle imaging.

High spatial resolution-such as ground resolution of meter level and centimeter level.

Hyperspectral resolution-such as nano-spectral resolution (for example, there are more than ten levels of visible spectrum).

High temporal phase resolution-if the repeated observation period reaches the hour level.

3. 1.2 New technologies and methods for remote sensing image processing are constantly emerging.

Theories and methods of new developments and trends, such as mass data compression, data fusion, seamless mosaic of large-area images, spectral reconstruction, mixed spectral analysis, ultra-multidimensional spectral image information display, information extraction modeling, intelligent processing, SAR information processing and imaging theory, multi-band and multi-polarization image analysis methods, etc.

When high spatial and hyperspectral resolution remote sensing appeared, a series of technical and methodological problems were put forward: with the improvement of resolution, the amount of remote sensing data increased geometrically and became so-called "massive data". Processing these massive data is naturally restricted by storage, speed and time, so data compression is necessary; Hyperspectral resolution enables us to identify more "fine" ground objects, and how to separate, reconstruct and display the spectra of these fine ground objects from the mixed spectra of images becomes the key of technical methods.

The same platform can obtain data with different ground resolutions. How to make the data with different ground resolutions meet the actual needs of different scales is very important, and data fusion is limited by geometric accuracy and spectral fidelity. In order to meet the actual needs, there are many fusion methods.

Large geographical area is the advantage of remote sensing, but the coverage of a satellite remote sensing image on the ground is always limited, and this limitation is narrowing with the improvement of ground resolution. Now people's demand has far exceeded this limit. For example, in an area of tens to hundreds of square kilometers, images of dozens to hundreds of scenes need to be spliced, so the images of many scenes may be uncoordinated in color and tone due to time difference. In order to coordinate the whole image, seamless stitching technology came into being.

3.2 New Development and Trend of Geographic Information System Technology

Integration of attribute data and spatial database management;

Multiple data format conversion;

Integration and standardization of basic geographic information system;

Secondary development of professional application;

Development and improvement of WebGIS, etc.

3.3 New progress and development trend of GPS technology

High-precision third-generation global positioning system:

Galileo global positioning system.

3.4 Integration of Remote Sensing, Geographic Information System and Global Positioning System (omitted)

4 Earth science applications and examples

4. 1 geoscience application

Nowadays, remote sensing geographic information system has been widely used in the field of earth science. Although the application sequence and effect are different, it has attracted people's attention and attention, and some of them have become industry norms. According to incomplete statistics, it can be divided into the following aspects:

(1) application of regional geological survey,

(2) Investigation and application of mineral resources,

(3) application of water resources and water environment monitoring,

(4) Application of land use monitoring,

(5) Application of land desertification monitoring,

6. Coastal resources development and environmental protection,

(7) Investigation and application of ocean island reefs and shallow seabed topography,

(8) application of ecological environment monitoring,

(9) Investigation and application of regional geological environment,

(10) disaster monitoring application,

(1 1) urban planning applications (including digital cities),

(12) Application of regional planning.

…………

4.2 Example

Up to now, there are countless application examples, but two aspects are worth noting: on the one hand, it is the regular understanding and achievements of previous applications, on the other hand, it is the frontier exploratory achievements.

4.2. 1 Conventional knowledge and achievements

The regular knowledge and achievements obtained by predecessors are also quite rich, which deserves our serious absorption. Due to the limited teaching time, we can only cite one or two. The author thinks that no matter where remote sensing geographic information system is applied, the technical method of information extraction is the same, which is also the technical key to solve practical problems. Therefore, three examples from different fields are used to illustrate the characteristics and characteristics of remote sensing geographic information extraction mode.

Remote sensing geoscience information extraction model;

Example 1: application of remote sensing in geological survey of gold deposits,

Example 2: Application of Remote Sensing in Land Desertification Monitoring,

Example 3: application of remote sen in salt lake monitoring.

4.2.2 Frontier exploration achievements

Among many frontier exploration achievements, the author thinks that the application of hyperspectral remote sensing in mineral identification is a difficult and hot spot at present. Example: "Study on Mineral Mapping by Hyperspectral Remote Sensing" (omitted)

5. Theory and technical methods.

5. 1 Theoretical problems

5. 1. 1 The problem of isomorphism or isomorphism of foreign bodies.

As mentioned above, the electromagnetic radiation characteristics of ground objects are the most basic theory of remote sensing, and people use the differences of spectral characteristics of ground objects to identify different ground objects. However, in practical application, there is a phenomenon that the spectrum of foreign objects is the same or the spectrum is the same, that is, the spectral characteristics of different ground objects are the same, so remote sensing can not play a role.

5. 1.2 Randomness and non-randomness of ground objects distribution

In the application of remote sensing, it is generally believed that the distribution of objects in a large geographical area is random, so a set of probability statistics methods can be used to enhance and extract the information of target objects, which is often successful, so there is a set of perfect methods in image processing software to meet the requirements of thematic information extraction. However, the distribution of actual objects is still non-random, so the probability statistical method is invalid. For example, the distribution of some ground objects has self-similarity, which is solved by nonlinear fractal dimension method. For example, there are fuzzy theory and artificial intelligence theory to complete the corresponding tasks.

5.2 Technical and methodological issues

5.2. 1 The spectrum of the measured object is inconsistent with that of the remote sensing image.

The measured ground object spectrum includes indoor standard sample spectrum and field measured ground object spectrum. Remote sensing image spectrum is a real-time mixed spectrum of pixels obtained immediately. There are differences in observation time and pixel resolution between them, and their spectra are obviously different, sometimes very different, which need to be analyzed and processed.

5.2.2 Timeliness and Regionality of Ground Object Image Spectrum

The image spectrum of some ground objects will change with different phases, such as vegetation and soil, which can be called temporality; The spectrum of some ground objects will change with different regions, just like a rock in wet and dry regions, its spectrum is different, which is called regionality. We must pay attention to these characteristics in application and take necessary measures.

5.2.3 Non-uniqueness of enhancement and extraction methods of ground object information

There are many methods to enhance and extract remote sensing image information. Although many methods are recognized, they are not unique. Especially when enhancing and extracting hidden information and weak information, some methods don't work, which doesn't mean that they can't be extracted, but they may not have found a suitable method and need further discussion.

refer to

Chen et al. Dictionary of remote sensing. Beijing: Science Press.

Chen et al. Overview of remote sensing resources. Beijing: Science Press.

Emma Nye. 1997. Remote sensing information model. Beijing: Peking University Publishing House.

Chen. 1998. Research on remote sensing information mechanism. Beijing: Science Press.

Fu suxing. 2002. Thematic analysis of remote sensing and geoscience atlas. Beijing: Science Press.

Li Shukai. 2003. Remote sensing spatio-temporal information integration technology and its application. Beijing: Science Press.

Zeng Zhiyuan et al. 2004. Computer classification of satellite remote sensing images and its geoscience application. Beijing: Science Press.

Wei Zhongquan.2001. Synthetic aperture radar satellite. Beijing: Science Press.

Sun Tianzong et al. 1995. Urban remote sensing. Shanghai: Shanghai Science and Technology Literature Publishing House.

Remote sensing of land and resources (quarterly) 1990 to this issue.

User newsletter. Remote Sensing Satellite Ground Station of China Academy of Sciences (quarterly) 1998 to this issue.

Chen Jianfei. 2004. Introduction to Geographic Information System. Beijing: Science Press.

He Jianbang et al. 2003. Principles and methods of geographic information sharing. Beijing: Science Press.

Li Hongtao. 2000.GPS application design. Beijing: Science Press.

Geographic information world. China Geographic Information System Association (quarterly) 1995 to this issue.

Zhang Yongsheng et al., 2005. Application of high resolution remote sensing satellite-imaging model, processing algorithm and application technology. Beijing: Science Press.

Zhao et al 2003. Principles and methods of remote sensing application analysis. Beijing: Science Press.

Cheng Cheng et al. 2004. Uncertainty of remote sensing data. Beijing: Science Press.

Qian lexiang 2004. Remote sensing digital image processing and geographic feature extraction. Beijing: Science Press.

Li Tianwen. 2005.GPS principle and application. Beijing: Science Press.

Guoan Tang et al. 2004. Remote sensing digital image processing. Beijing: Science Press.

Kuang Shengai et al. 2002. Remote sensing monitoring of land desertification in farming-pastoral ecotone. Remote sensing of land resources.

Tian et al 2005. Quantitative analysis of total salt content in Zabuye Salt Lake in Tibet by remote sensing. Modern Geology, 19, No.4, 2005.