Osgearth development data preparation (I) -- DEM and texture image (remote sensing) download and processing (transfer)

Osgearth development data preparation (I) -- DEM and texture image (remote sensing) download and processing classification: Open Source GIS 1418 people read comments (0) collect reports osgeardem remote sensing geographic information Google Images

Directory (?) [+]

1. How to obtain data
2. How to obtain data on the network
1. Important databases in China
2. Others
3. More
4. Important foreign Databases
5. University of Maryland
6. Harvard University
7. NASA
8. Aster gdem
9. Other important resources
1. Data sources in the form of personal websites
2. Borrow commercial data
3. How to Select data
4. Reference
1. Section 1 modified the website of the International Scientific Data Platform

How to obtain data

The digital elevation data is finally downloaded. It took a week to get the data. Although there is not yet a set of high-precision global digital elevation data that can be used for free, there are still many ways for us to find a set of available data, which requires careful screening. In the course of research, there are only several ways to find data:

1) people who have done relevant work can provide some practical data. However, the amount and quality of data obtained in this way are also unsatisfactory. It is easy to make a small experiment, in case of a large project, it is very difficult to make a difference.

2) many universities and research institutions, such as the University of Maryland and NASA, provide a large amount of data available for free on the Internet. Most of the data can support a large project. Secondly, on many personal blogs, some netizens enthusiastically provide download links, which may discover a huge treasure. Once again, through some improper intrusion, some stolen tools can also be used to obtain better resources. Network Access methods are limited. First, the device must be connected to the Internet. The data quality is not guaranteed, but it is only a compromise solution, which will be described in detail later.

3) measurement and acquisition by yourself through experimental means consume a lot of time and energy, and the price of measurement tools will ultimately affect the possibility of implementation of this approach, in addition, the obtained data has great limitations, and often only obtains static data on a temporary basis, which cannot meet the needs of dynamic updates.

4) In commercial projects or research projects with sufficient funds, you can also spend some money to seek cooperation from professional data production companies. The most obvious disadvantage of this access method is that a large investment is not suitable for individuals and small projects, but its advantage is that this method can achieve all the work that cannot be done in the above ways. Professional data companies will invest manpower and resources in data acquisition, and provide full support for data processing and updating and using. (Power of Kong fangxiong :))

How to obtain data from important databases in China on the network

The preceding section briefly describes several primary methods for obtaining spatial data. Compared with other methods, obtaining available raw data from a network data source serves as a balance between data quality and resource consumption. Here I mainly provide some available data, which will be briefly introduced by the way. The basemap data required for building an osgearth application includes vector maps, road network data, place name data, satellite images, and terrain data. In order to build a terrain-fluctuating effect, terrain is required first. This data can be downloaded from the international scientific data platform of the Computer Network Information Center · scientific data center of the Chinese Emy of sciences: international scientific data service platform. Shows the portal for downloading elevation data:

In fact, the current data on this data platform is mainly related to geographical information. In addition to data images opened in foreign countries, there are also self-made product data. In addition, it also provides some practical scientific data models for users. Is the homepage of the Data Platform:

It needs to cover the world and more detailed data. In addition, there are other major data sharing platforms available in China. The China Polar Research Center provides a Polar Science Data Sharing Platform. Here, users can find scientific data on Earth information science, environment, ecology, and other aspects of the North and South Poles, with a wide range of disciplines. The platform also allows users to upload scientific data, the following is the homepage of the Platform:

Using this data sharing platform, we can get some blank elevation data and image data, which can also expand the business of the platform we built with osgearth to the field of scientific research.

Others

Other databases such:

Earth System Science Data Sharing Platform: http://geodata.nju.edu.cn/Portal/index.jsp

This platform contains links to many useful other sharing platforms, which can provide us with better data options.

China Meteorological Science Data Sharing Service Network: http://www.cams.cma.gov.cn/cams_kxsy/qky_kxsy_index.htm

The Chinese Emy of Sciences land system theme database: http://www.data.ac.cn/

This database has many resources related to natural geography. If you need relevant data, you can refer to the relevant content in this database.

More

Here are more available domestic sharing platforms:

1. China Natural Resource Database http://www.data.ac.cn/

2. China Lake database http://www.lake.csdb.cn/

3. http://www.marsh.csdb.cn/

4. China soil database http://www.soil.csdb.cn/

5. Northeast black soil agricultural ecological database http://www.blackland.csdb.cn/

6. http://www.sdb.ac.cn/sdb/database/ of agricultural ecological database in Subtropical Region

7. China mountain environment and disaster database http://www.mountain.csdb.cn

8. http://www.loess.csdb.cn/

9. China Cold Area Special Database http://www.careeri.csdb.cn/

10. Xinjiang Resources ecological environment database http://www.oasis.csdb.cn

11. China rock and mineral chemical database Co., http://www.geochem.csdb.cn/

12. China ry database http://www.geotectonics.csdb.cn/

13. http://www.atmosphere.csdb.cn of atmospheric science and environmental database

14. National Resource and Environment Remote Sensing database http: // 159.226.117.112/rsdata/

15. http://www.satimage.csdb.cn of Remote Sensing Satellite Image Retrieval Database

16. Dynamic land survey and resource environment database http://www.dynamicgeodesy.csdb.cn/

17. Nanhai marine science database Co., http://www.southchinasea.csdb.cn.

18. China Earth System Science Data Sharing Network http://www.geodata.cn

19. Meteorological Research Database http://www.cams.cma.gov.cn

20. China Sustainable Development Information Network Database http://www.sdinfo.net.cn

21. Qinghai-Tibet Plateau scientific database http://www.wdcd.ac.cn/qzdc/index.htm

22. Qinghai-Tibet Plateau database http://www.cams.cma.gov.cn/

23. Plateau Meteorological Database http://www.cams.cma.gov.cn/htdocs/xxgx.htm

24. China Hydropower statistical data Co., http://www.sp.com.cn.

25. China Water Conservancy yearbook http://www.waterpub.com.cn

26. Power statistical data http://www.sp.com.cn

27. http://www.stats.gov.cn of hydraulic statistic Database

28. Water Conservancy Statistical Bulletin http://ghjh.mwr.gov.cn

29. China Water Resources Bulletin http://www.mwr.gov.cn

30. China State Water Affairs annual report http://www.hydroinfo.gov.cn

31. Marine Resource Database http://www.coi.gov.cn

32. China Environmental Protection database Co., http://www.ep.net.cn.

33. Yangtze River Basin natural disaster database http://changjiang.whlib.ac.cn

34. National Resource Environment Data Center http://zls.nenu.edu.cn

35. Marine space database http://sdinfo.coi.gov.cn

36. Forest Resource Sharing database http://sdinfo.forestry.ac.cn/

37. Standard climate value http://cdc.cma.gov.cn for major cities in China

38. Earth Environment and Climate Change Database http://www.sdinfo.net.cn/

39. Atmospheric Environment Database http://www.cams.cma.gov.cn

40. Sandstorm database http://www.cams.cma.gov.cn in Western China

41. China Hail database http://www.cams.cma.gov.cn.

42. Western China Climate Resource Database http://www.cams.cma.gov.cn

43. China Disaster Weather Database Co., http://www.cams.cma.gov.cn.

44. China Climate standard value database Co., http://www.cams.cma.gov.cn.

45. China Polar Research Database http://www.cams.cma.gov.cn

46. National Environmental Statistics Bulletin http://www.zhb.gov.cn

47. China Environmental Status Bulletin http://www.zhb.gov.cn

You can refer to the professional websites listed above based on your specific needs.

Important foreign Databases

The foreign resources focus mainly on the open databases provided by NASA and the University of Maryland, where we can find some practical spatial information data.

University of Maryland

 

Harvard University has a column of data resource at the geographic analysis and research center of Harvard University, which also contains a large amount of GIS data, the most rare of which is a historical database about ancient Chinese territory, this database is stored in ESRI shapefile format, and osgearth itself supports the SHP format. This data can be used well by osgearth. The following figure shows the main interface of the data: the portal of the main interface is displayed in the data resource column, as shown in. The China historical database search tool is under the CGA data sharing list:

NASA

NASA data search interface: http://reverb.echo.nasa.gov/reverb/#utf8=%E2%9C%93&spatial_map=satellite&spatial_type=rectangle

The data here is very rich and covers a large number of Earth science-related data and has a large number of databases. However, it is difficult to download NASA data, the download information obtained after login must have a specific download tool. For details, refer to the data tutorials provided by NASA and the instructions provided by the system.

 

Aster gdem

Data sources of other important resources in the form of personal websites store some simple shapefile vector data on this website, data on national boundaries, meteorological data, species, vegetation, elevation, and Remote Sensing of various countries around the world, including related data of different scales.

Although commercial data borrowing is excellent in all aspects of data services, it takes a certain amount of money to obtain it. However, research may not necessarily support a large amount of money, therefore, we can consider using some commercial data as experiment materials. On this basis, we should pay attention to the support for genuine copyrights of data providers. You can use some specific tools to obtain data in the specified region from the servers of these data providers. Typical tools include rice songs and water injection. When using, you must pay attention to the need to use global Mapper to correct the loss of projection coordinates of the downloaded image data (download the er integrated with the original Chinese Version). For more information, see the help documentation of er, note a) if a large number of images need to be set to Google map projection, you can select batch conversion/re-projection under the menu bar of the global mapper file, as shown in. B) when the projection coordinate is input by epsg, the epsg code of Google map is 3785. If it is converted to WGS 84 projection later, the epsg code is 4326. You can also search for the epsg code of other projection systems. For the specific performance of the software, please pay attention to the official websites of the two software. How to Select data.

The most important aspect of data is their purpose, followed by accuracy and quality. Precision refers to the richness of the obtained data content, whether to display details as much as possible; quality mainly refers to the correctness of the data, as long as the measurement data system runs normally, the correctness of the obtained data can be guaranteed.

For image data, its precision is directly reflected in the spatial resolution of the data. In other words, it is the actual spatial distance represented by each pixel in the raster data, the 30-meter precision of the elevation data shown above represents the space range of 30-meter x 30-meter in the real world. Similarly, an elevation data table with a precision of 90 meters is a pixel in a raster image that represents the spatial range of 90 meters x 90 meters in the real world.

The quality of data is whether the obtained data is correct and whether there are interference factors that affect data usage. For example, the failure of Landsat-7 * caused the loss. There is no possibility of retrieving actual data for lost data. Therefore, you can only use the padding method to make up for the missing data, in addition, 70-80% of the data is relatively intact. As shown in:

Pay attention to these issues when selecting data. The higher the data precision, the larger the data volume ,:

The data with 1KM precision is about 600 m, the data with M precision is about m, and the data with M precision is close to 2G. Therefore, when selecting data: Make a trade-off between precision and data volume !!! However, the higher the data quality, the better the information, and the clearer the information.

Refer: Lansdat *Http://datamirror.csdb.cn/landsat/files/gap.jsp on section 1: International Scientific Data Platform changed site: http://www.gscloud.cn/website name also changed to geographic space data cloud