Foreword

In recent years, with the accelerated development of China's urbanization process, the land occupation of various types of construction is increasing, and the task of land survey and determination is very heavy. The land surveying and measuring community is not only a specific work in surveying and mapping, but also a technology for land use. Service work, and to strengthen the review of various types of land use, to strictly control the occupation of cultivated land in non-agricultural construction, to ensure the legal, scientific, intensive, and standardized land use has played an important role, so that the use of land examination and approval work to be more scientific, institutionalized and standardized. In order to further standardize the work of land survey and determination, China's Ministry of Land and Resources (Guo Tu Zi Fa [2007] No. 125) issued the "Regulations for Land Survey and Determination" TD/T1008-2007, which was implemented from September 2007. It has been more than a year since. The land survey and measurement community is based on the needs of land use conversion, land development and reclamation, land supply, cadastral survey, land registration, agricultural land conversion, land use planning, land development, consolidation, and reclamation. In the field, the scope of land use, the location of the measured boundary, the current status of land use, the administrative boundary, the area of ​​various types of land, and the area of ​​land used for calculation shall be used to calculate the classified area and total land area of ​​the statistical land, and the approval and review of the conversion of agricultural land. The land resources development and management project, such as project establishment, approval, implementation, land supply, circulation and property rights registration, provide scientific and accurate technical services for maps, numbers and materials.

I. Control measurement strategy in the field of land survey and measurement
Engineering Control Measurement is the general name for the plane control measurement and elevation control measurement established by industrial construction measurement. In the land survey measurement area, the measurement is made for the geodetic, photogrammetric, topographic and engineering measurement. There are usually plane control measurements, which are performed to determine the plane coordinates of the control points; the second is the elevation control measurement, which is performed to measure the elevation of the control point; the third is the three-dimensional control measurement, which is to simultaneously determine the plane coordinates of the control point. And elevation or spatial 3D coordinates. The first-level control network of the land survey and measurement industry is arranged according to the four-wire network and the GPS network. Usually we use the total station for traverse measurement. When the measurement equipment is licensed, it should be arranged as a GPS network. It can be positioned in static or fast static GPS mode. For example, in the control measurement, we use three southern S82 dual-frequency GPS receivers to observe, and prepare the ephemeris forecast map before observation, and make an observation schedule to select the appropriate time period for observation. Using two known points, and the others are unknown points, in order to reduce the projection distortion, we use a 3-degree band projection and set the central meridian to 117°. Assume that the density of the first-level control network does not meet the land survey and measurement boundary of the construction project. We need to set a level 1 or secondary encryption control point on the basis of the first-level control point. Encryption control measurements require the use of a wire mesh or a single wire. For the three-dimensional constraint adjustment, the error in the unit weight reaches 2 cm, and the relative accuracy of the weakest edge needs to reach 1/2 million until the accuracy requirement is fully achieved. And through the network, the coordinate conversion parameters (seven parameters) of the test area are obtained for subsequent RTK dynamic measurement use.

Second, the boundary point measurement in the land survey and measurement community
The boundary point measurement refers to the measurement taken to obtain the geometric position of the boundary point space. And it is generally controlled by a known control point, and is measured by a wire measurement, a polar coordinate method, an orthogonal method, or the like. In the land survey and measurement industry, in order to ensure the reliability of the site layout and the accuracy requirements of the boundary point coordinates, the boundary point measurement should be performed by the analytical method after the boundary pile is laid. The boundary measurement is usually done using the polar coordinate method. Stations must be placed at known control points. The angle half-measurement measurement is that the error of the theodolite to the point must not exceed 3 mm. After the end of the station, the rear view direction must be checked. The required deviation should not exceed ±30". In the distance measurement, electromagnetic wave distance measurement or steel rule measurement can be used. When using electromagnetic wave ranging, the distance is generally not more than 200 meters, and the individual is relaxed to 300 meters. When measuring with a steel ruler, the distance should not exceed 2 feet. At least one boundary point should be detected by the adjacent station. The boundary point is the accuracy. When the base station is set, the point at the middle of the measurement area is 1. The conversion parameter obtained before is input in the mobile station handbook after the base station is started, and the correction wizard is required to input the coordinates of the base station. Correction, in order to verify the conversion parameters and the accuracy of the correction, the mobile station checks to another known point before starting the operation, and the measurement is started after the accuracy is passed. The two mobile stations simultaneously measure one boundary line and require one. From the starting point, the other is measured from the end point, and the speed of the operation is significantly faster than the traditional total station measurement. The development of technology can also be carried out by GPS-RTK method, but the observation time at each point should not be less than 5s, and the point precision can reach 1 to 2 cm. The analytical method is used to determine the point of the boundary point coordinates relative to the adjacent control point. The error control range in the position is within ±5 cm. The difference between the coordinate back-calculation distance and the field measurement distance between adjacent boundary points should be within ±10 cm.

Third, ownership investigation and land type judgment
The boundary of land ownership has not changed, and the original Land Tenure Agreement has complete contents, standardized texts, and complete legal procedures. It is not necessary to re-investigate and use the original Land Tenure Agreement. If the land ownership boundary changes or the previous investigation is wrong, the confirmation of the land ownership boundary needs to be organized by the local land and resources administrative department, and the relevant personnel of the relevant ownership unit shall follow the “Technical Regulations for the Investigation of Land Use Status” and “City The cadastral investigation procedures and the “Several Provisions on Determining Land Ownership and Use Rights” require that they be jointly directed to the site and map the boundaries of ownership to the working base map. According to the national unified land classification, using the cadastral map, the land use status map or the relevant land use type boundary on the topographic map, through the on-site investigation and field interpretation, the land use type boundaries within and near the land use will be mapped or mapped. On the work base map, and mark the three-level land use type number. At the same time, if the land use type of the land use status survey is verified and is inconsistent with the actual situation, it shall be handled in accordance with the relevant provisions of the change of cadastral survey.

Fourth, the land survey and determination map
The land survey and measurement map is a regional professional map that integrates various cadastral elements, current status of land use, and topographical and geophysical elements. And using the coordinates of the measured boundary points and the elements of the ownership and land type measured by the field survey are formed on the cadastral map or the topographic map or directly mapped. The land survey and measurement boundary map includes: the boundary point within the land use area, the boundary line, and the total land area. However, for large-scale construction land projects, due to the large number of land surveying and mapping maps, the total area or list of land used in the first map should be filled to the primary classification area. At the same time, the name and land code of each ownership unit occupy the land area and land area of ​​each ownership unit, and the land code and area of ​​each type of map. Administrative boundaries, land boundaries, features on the ground, text notes, mathematical elements, etc. Therefore, it is necessary to pay attention to the land survey and determination map: First, the scale of the land survey and determination map is usually 1:500, but at least it should not be less than 1:2000. Second, within the scope of land use on the land survey and determination map, each tenure unit is required to note the name and area of ​​the tenure unit at the appropriate location, and the land number and area should be noted in the appropriate location for each parcel. The third is the land survey and measurement boundary map. The boundary line of the land for the project can be expressed by the solid line of 0.3 mm red according to the size of the land. The boundary point is represented by a red circle with a diameter of 1 mm. The boundary of the land boundary is 0.3 mm. It is expressed by a black dotted line with a pitch of 1.5 mm.

references:
[1] Song Yuhong, Zheng Jianmin. Two Methods for Calculating the Area of ​​Land Survey and Measurement[J]. Science & Technology Information (Academic Research), 2007, (25) .
[2]辜 蓉蓉, HAN Guangcong, ZHANG Mengdong, DENG Jing. Discussion on the function of construction geotechnical surveying boundary [J] Surveying and Mapping Science, 2007, (01)
[3] Wang Jianlin. Application of GPS Measurement Technology in Engineering Surveying and Mapping [J]. China New Technology and New Products, 2010, (17) .
[4] Yang Honggang. Application of GPS Real-Time Dynamic (RTK) Measurement in Engineering Survey[J]. Railway Survey and Design, 2008, (03) .
[5] Department of Land and Resources of Anhui Province, Technical Supplementary Rules for the Second Land Survey (Rural Land Change Survey) of Anhui Province. 2008.

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