Making the Basemap of the Second National Land Survey in Henan Province

The second national land survey, as an important survey of national conditions and national strength, aims to find out the current situation of land use in the whole country, master the real basic data, establish and improve the system of land survey, statistics and grading, realize the socialized service of land resources information, and meet the needs of economic and social development and national strength of land resources. Doing a good job in the second land survey and mastering real and accurate land data are the objective requirements for fully implementing Scientific Outlook on Development, building a resource-saving and environment-friendly society and promoting comprehensive, coordinated and sustainable economic and social development. It is an important part of promoting the coordinated development of urban and rural areas, ensuring national food security, promoting social stability and protecting farmers' interests. It is an important basis for compiling national economic and social development plans, strengthening macro-control of the national economy and implementing scientific decision-making; It is an urgent need to implement the State Council's Decision on Deepening Reform and Strict Land Management (Guo Fa [2004] No.28) and improve the government's administrative ability according to law and the level of land and resources management; It is the basic means of scientific planning, rational utilization, effective protection of land resources and implementation of the strictest farmland protection system.

Making the base map of Henan 1 ∶ 1000 standard framing survey is an important link in the second land survey in Henan province. Based on Xi 'an coordinate system 1980, it takes space remote sensing data as the main information source, and uses space remote sensing technology and other auxiliary technical means to produce qualified 1 ∶ 1000 standard framing survey base map, which lays the foundation for subsequent land survey.

data source

From 2005 to 2007, the Information Center of the Ministry of Land and Resources of Henan Province undertook the pilot project of "High Resolution Image Data Processing and Database Construction" in Henan Province, such as the "863" project of the Information Center of the Ministry of Land and Resources "Large-scale and Efficient Remote Sensing Monitoring Operational System of Land and Resources (2003aa131kloc-0/0065438). Through "high resolution image data processing and database construction", the digital orthophoto map of SPOT 5_2.5 m covering Henan Province from 2004 to 2007 was made in Beijing coordinate system (including 4 scenes in 2004, 0/7 scenes in 2005, 36 scenes in 2006 and 2007/kloc-). The land use database of Henan province 1∶ 1 Wanxian county and the graphic image database of GPS control points in Henan province were built, which laid the foundation for the second adjustment map of Henan province.

Because the satellite image required by the Second National Land Survey Office of the State Council was in 2005, some satellite images received during the pilot period were affected by clouds, fog and haze, and a few original images were overstretched, and the spectral and texture characteristics of the images were disturbed, which could not meet the technical requirements of the second survey map making. Through various communication with the Cartographic Group of the Second National Land Survey Office in the State Council, 63 scenes in the original SPOT 5 satellite image can be used to make the base map of the second survey, and the unqualified image data will be reprogrammed and replaced by the second survey office. The distribution of qualified images is shown in Figure 8- 16.

Figure 8- 16 Data Distribution Map of Image Results of the Second Land Survey and Utilization Project in Henan Province

8.3.3 Completion of Basemap Making Task

According to the requirements of the project contract, * * * undertook the task of making the base map covering the total area of Zhengzhou and other cities 108768 km2. See Figure 8-65, 438+07 for the scope of tasks. In the later stage, due to satellite data reception and other reasons, the task of making 2364km2 and 167 standard maps was added in two batches. The production situation of each batch is as follows:

Figure 8- 17 Distribution Map of Production Project Area of the Second Land Survey in Henan Province (project contract scope)

The first batch 165438+200710.30 was submitted to 25 counties (cities, districts) in Zhengzhou, Luoyang, Anyang and Puyang, involving a total of 1: 157;

The second batch was submitted to 43 counties (cities, districts) such as Luoyang, Pingdingshan, Xinxiang, Jiaozuo, Xuchang, Luohe and Jiyuan on June 5438+February 3, 2007, involving a total of 1597;

The third batch was submitted to 20 counties (cities, districts) in Sanmenxia, Xuchang, Luohe, Nanyang and Zhumadian on June 5438+1October 365438+1October 0, 2008, involving a total of1344 pieces;

The fourth batch was submitted to Weishi, Yanling, Shangshui, Shangcai, Suiping and runan county (cities, districts) on May 27th, 2008, involving 1: 133 pieces;

The fifth batch was submitted to 9 counties (cities, districts) including Shaanxi County, Lingbao, Lushi, Luoshan, Huangchuan, Gushi, Guangshan, Xinxian and Shangcheng on July 4, 2008, involving 642 maps with a total scale of 1: 1000.

The sixth batch, submitted on July 3, 2008, was scattered in Anyang, Xinxiang, Hebi, Zhengzhou, Kaifeng, Shangqiu, Sanmenxia, Nanyang, Zhumadian and Xinyang, involving 79 maps of 1: 1 10,000;

The seventh batch, submitted on February 7, 2009, was scattered in Nanyang, Kaifeng, Zhoukou and other cities, involving 88 sheets 1: 10000.

The actual mass production range is shown in Figure 8- 18.

Figure 8- 18 Map of Actual Production Scope of the Second Land Survey in Henan Province

This project * * * produces 1: 1 000 sheets, with a total area of 1 1.9573 million km2 and an effective area (in Henan Province)1.1

8.3.4 Making of Surveying Basemap

TopLand (Figure 8- 19), a software package for the second national land survey, is used to make survey maps. Nesting the mosaic image of the project work area with the civil administration boundary at or above the county level issued by the Second National Land Survey Office of the State Council, automatically cutting out the DOM of the1:1000 standard map sheet, and making the corresponding map sheet decoration file and DOM primitive file.

Figure 8- 19 Software for Making Basemap of the Second National Land Survey

8.3.4. 1 standard framework DOM and outline decoration

Taking the range of 1 cm outside the rectangle in the standard drawing as the inner drawing, the standard framing DOM is made by using the map arrangement module of TopLand software, and the areas lacking images in the DOM drawing are filled with white. At the same time of making standard framing DOM, the software automatically makes corresponding profile finishing files with standard framing as the unit (Figure 8-20).

Figure 8-20 Standard framing survey base map

8.3.4.2 graphic file making

Generate DOM metadata files in batches by using the metafile production module of TopLand software.

The content and filling method of metafile are shown in Figure 8-2 1.

(1) file organization and management. Standard framing management folder: 65,438+0 ∶ 65,438+00,000 Standard framing DOM results take standard framing as the basic unit, and its folder name follows the number of standard framing frames. The folder contents include standard framing DOM and its metafiles, contour trimming files, etc.

See Table 8-2 for the contents, file names and formats of the standard framework management folder.

Table 8-2 Management File Contents and Naming Rules

Fig. 8-2 1 DOM metafile schematic diagram

(2) Management documents of surveying and mapping base map project in county-level jurisdiction. Establish the project management document of surveying base map with the complete county-level administrative region as the unit, manage all standard framing DOM, joint map and administrative (civil) boundaries above the county level involved in the jurisdiction, and use the full name of the jurisdiction, as shown in Figure 8-22. Using the project management folder making module of TopLand software, the project management files of county-level jurisdiction survey base map are generated in batches.

Figure 8-22 County Surveying Basemap Project Management File

Submission of results

According to the organizational requirements and methods of the Technical Specification for Basemap Production in the Second National Land Survey, * * * submitted the survey results in seven batches. The results include process results and final results, in which the process results include the production of space DOM and the process results of GPS measured points, vector data and documents, and the final results include the results of surveying base map and GPS measured points.

8.3.6 Existing problems

(1) Henan province1∶ 50,000 DEM was used in this production task, which was made earlier and the present situation is poor. Because the road construction and excavation in some areas are inconsistent with the field, the data in some areas of orthophoto are distorted, and the deformation of image data received from different directions is not the same.

(2) The viewing angle of the receiving side of some mountain image data is too large, especially the viewing angle of some mountain images in western Henan, northwestern Henan and southwestern Henan is more than 20 degrees, which leads to the phenomenon of watching adjacent landscape images left and right, which leads to the phenomenon of pulling flowers or local dislocation after orthorectification of some mountain image ridges.

To sum up, in this production task, the GPS control points measured in the field are used as the control data for image orthorectification, and the technical methods adopted meet the requirements of the Technical Regulations for the Production of Basemaps in the Second National Land Survey. The results submitted by the project are complete and standardized, which successfully passed the quality inspection of the supervision unit, providing a guarantee for the implementation and timely completion of the rural survey task of the second national land survey in Henan Province.