I. Introduction to the internship unit
Zhongnan Survey and Design Institute was founded in 1955, and was originally the Zhongnan Branch of the Comprehensive Survey Institute of the Ministry of Architecture and Engineering. It was affiliated to Hubei Province in 1971, and it was one of the earliest key survey and design units established in China. At present, Zhongnan Survey and Design Institute has Grade A engineering survey (comprehensive), surveying and mapping, consulting and Grade B engineering design qualifications. The institute consists of various geotechnical technologies, architectural design institutes, Hubei Zhongnan Geotechnical Engineering Co., Ltd. (first-class foundation and foundation engineering construction qualification), Hubei Zhongnan Engineering Construction Supervision Company (first-class qualification) and Hubei Geotechnical Water Resources Engineering Technology Development Company (Wuhan Donghu High-tech Enterprise), and has branches in Shenzhen, Yichang, Hubei and Xinyang, Henan.
II. Introduction to the internship site
Yunfu City is located in the central and western parts of Guangdong Province, south of the middle reaches of Xijiang River. It borders Zhaoqing and Jiangmen in the east, Yangjiang and Maoming in the south, Wuzhou in Guangxi in the west, Xijiang in the north and across the river from Fengkai and Deqing counties in Zhaoqing. The urban area is 61 kilometers away from Zhaoqing, 161 kilometers away from Guangzhou, 177 nautical miles away from Hong Kong by waterway, and 61 nautical miles upstream from Wuzhou, Guangxi. The whole city is within the range of 22.22'-23.19' north latitude and 111.13'-112.3l' east longitude. The total land area of the city is 7779.1 square kilometers. In 1998, the city's cultivated land area was 1.252 million mu, including paddy field area of 1.112 million mu and hillside below 25 degrees of 1.3143 million mu. Yunfu City has jurisdiction over Yuncheng District, Yunan County, Xinxing County and Yun 'an County, hosting luoding city, including 55 towns and 11 streets.
the position of Yunfu city in Guangdong province
iii. the purpose of production practice
production practice is an indispensable part of our professional knowledge structure of surveying and mapping engineering, and it is included in the professional teaching plan as an independent project. Its purpose is to enable students to acquire perceptual knowledge of basic production through practice, integrate theory with practice and expand their knowledge; At the same time, professional production practice is an important channel to train and cultivate students' professional ability and quality. It is also an important way for students to get in touch with society, understand the industrial situation and understand the national conditions, gradually realize the transformation from students to society, and cultivate our ability to take up technical work and understand the basic methods and skills of enterprise management. Experience the contents and methods of enterprise work. This practical knowledge is a very necessary foundation for us to study the following courses and even our future work.
iv. Production practice content
The 1: 511 topographic map survey was carried out within 21 square kilometers of the existing urban area of Yunfu City. The specific scope is: Muyang Road and Luosha Primary School in the east, transit roads in the west, Fuqian Road and Nanshan River in the south, and Gaofeng and transit roads in the north.
specifically:
(1) Plane control survey
Topographic control survey includes basic control survey and root control survey. The basic control points include national geodetic control points at all levels, GPS-C, D and E level points, second, third and fourth level control points in cities and towns, and first and second level control points.
the basic control points should be buried with fixed markers and marked with points.
traverse survey and GPS positioning survey can be selected for plane control survey.
the density of map root points should be determined according to the density of buildings in the survey area and visibility conditions, and the principle is to meet the needs of topographic elements mapping. Require no less than 64 points per square kilometer.
(2) Elevation control survey:
The fourth-class leveling adopts the middle wire reading method for one-way observation, and the branch line must be measured back and forth or one-way double-turning point observation. Before observation, the level and leveling rod should be calibrated. The items, methods and requirements of calibration can refer to the National Third and Fourth Class Leveling Specification.
(3) topographic mapping:
1: 511 digital topographic mapping of the urban area near Yunfu City and the land approved for approval in 2118. The survey area: the intersection of National Highway 324 and sanmao railway in the east (Yunbu Village, Silao Town); It is about 1.5 km (111-911 m) from north to south, about 31 km from east to west, and the survey area is about 15 square kilometers.
V. Technical requirements of the project
(1) Technical basis for operation
1. Specification for Revision and Survey of National Basic Scale Topographic Map (GB/ T14263-93)
2. Specification for Urban Surveying (CJJ 8-99)
3. Global Positioning System (GPS). T18315-2111)
5. Technical Specification for Urban Basic Geographic Information System (CJJ 111-2114)
6. National Third and Fourth Leveling Survey Specification (GB12898-91)
7. Third and Fourth Traverse Survey Specification (CH/ T 2117-2111)-State Bureau of Surveying and Mapping released on March 5, 2111
8. Technical Specification for Global Positioning System Urban Surveying (CJJ 73-97)-released by the People's Republic of China and the Ministry of Construction on April 25, 2197 (JB [1997] No.79). T7929-1995)-The State Bureau of Technical Supervision issued
11 on September 5, 1995. Technical Specification for Field Digital Mapping at 1: 511, 1: 1111 and 1: 2111 (GB/ T14912-2115)-The National Standardization Administration Committee released
11 on April 9, 2115. The latest 1: 11111 topographic map of Yuncheng District of Yunfu City
12. The result of plane control of Yunfu City: Yuncheng District of Yunfu City (with an area of about 791.8 square kilometers). The GPS-D level points and the related GPS-D level points around the area
13. The elevation control data of Yunfu City: the third-class leveling results in Yuncheng District of Yunfu City and the related third-class leveling results around the area < P > (2) The plane coordinate system, height system and basic vertical interval < P > provide two sets of coordinate system results respectively: < P > 1. Yunfu independent coordinate system.
2. The plane datum is 1981 Xi 'an coordinate system (hereinafter referred to as 81 coordinate system) and the elevation datum is 1985 national elevation (hereinafter referred to as 85 elevation).
(3) Technical method requirements
1. Plane coordinate system, elevation datum and basic vertical interval
plane coordinate system: 81 coordinate system is adopted;
height system: 85 elevation datum is adopted;
Basic vertical interval: 1.5m in flat land and hilly land, and 1.1m in mountainous area.
2. Mapping scale and mapping method
Mapping method: digital mapping by full analytical method;
mapping scale: 1: 511;
map framing: rectangular framing is adopted, with the map size of 41cm×51cm, and the field is 251 meters long from east to west and 211 meters wide from north to south; Code the kilometers of the coordinates of the outline points in the southwest corner of the map, with the X coordinate in the front and the Y coordinate in the back. Both X and Y coordinates are taken to two decimal places, and the middle is connected by a short horizontal line (coordinate numbering method).
(4) Accuracy requirements
The accuracy of control points must conform to the national standards such as Urban Survey Code, Global Positioning System (GPS) Survey Code, and National Third-and Fourth-Class Leveling Standard; The accuracy of topographic map must conform to the national standards such as Cadastral Survey Specification and Detailed Rules for the Implementation of Urban Cadastral Survey in Guangdong Province.
in order to meet the needs of land management and real estate management in our district, the detailed points related to the determination of ownership, such as houses, fences, kerbs and roads, The accuracy of plane survey shall conform to the following table:
the accuracy requirement of plane survey
the application range of the error in the point of the root point of the class relative to the adjacent map
1 ≤5cm general house corner, fence and other obvious features
2 ≤7.5cm concealed house corner, fence, curb and road in the old urban area
(5) topographic map data storage
house surface.
road surface: named roads at all levels, urban streets and roadways should be constructed, and the intersection of road surfaces should meet the topological relationship, that is, the points at the edges are completely coincident.
road centerline: road centerlines should be drawn for all levels of roads, urban streets and roadways with names (drawn in the office, without field mining points), and "road name" and "road width" (average width) should be filled in for the road centerlines. One road and one line are required, and roads are allowed to intersect.
placename marking points: placenames include township (street) names and village (neighborhood) names. It is required that the information of placenames in the survey area is complete and accurate. At the same time of drawing marking, it is required to fill in the attribute table of placename marking points with "placenames" consistent with drawing marking.
company name marking point: the company name includes the names of institutions, enterprises, institutions, companies, communities, etc. with fixed office space. At the same time of marking on the drawing, it is required to fill in the "company name" in the attribute table of the company name marking point consistent with the drawing.
water surface: classify and construct the water body, and fill in the "water body name" consistent with the drawing in the attribute information table
(6) submit the achievement materials
1. Instrument inspection data or instrument inspection certificate;
2. Record of control points;
3. observation handbook;
4. Adjustment calculation data and precision statistics;
5. Network diagram of control network (81 coordinate system), plane control joint survey diagram and leveling road map;
6.1: 511 topographic map: block map and sub-map.
VI. Internship Experience
The 44-day summer production internship has made me a surveying and mapping student who is about to enter the society gain a lot, whether it is work experience or life lessons, I think it will be improved for us. From plane control measurement to step measurement, we have been making progress. Compared with the previous classroom practice, the time is more concentrated, the content is wider, and the procedures are more systematic. It is based on measuring the actual production, deepening the further understanding, mastery and comprehensive application of book knowledge. It is an important teaching link to cultivate students' ability to integrate theory with practice, work independently, comprehensively analyze and solve problems, and organize and manage, and it is also a concrete, vivid and managerial one. It has more important significance in imparting knowledge, developing intelligence and cultivating comprehensive quality.
first of all, teamwork. This production practice also made me really realize that surveying and mapping major is a team work. Indeed, if a project is to be successfully completed, it is far from enough to rely on one person's strength and conception, and it is impossible to complete the task well. Only the cooperation and unity of all members of the team can make the task complete with good quality and quantity. As the saying goes, "three heads are better than one." In addition, this production practice has also cultivated our ability of division of labor and cooperation, enhanced the feelings between students and deepened friendship. It is inevitable that we will encounter some bumpy things in the internship process, which makes everyone unhappy, but we can communicate and communicate in time, forget yesterday's unhappiness and welcome the new sunrise.
secondly, the ability to work. Through this internship, I found that as a surveying and mapping undergraduate, my basic knowledge is still not solid, which is highlighted in the process of work. I will explain some individual details.
1. Plane control survey: Plane control survey has a front-rear prism. Because the precision of control survey is very high, it is a test for students who oppose the prism. The level bubble is centered, which requires a fairly high level. However, maybe the level bubble of the vertical prism is centered, but it is not allowed for the middle rod itself. Therefore, we aim at the bottom of the centering rod first, then fix the horizontal angle and move the line of sight to the prism lens, thus greatly improving the control accuracy. Of course, this method is still applicable to the orientation of graph root control and step measurement.
2. Sketch scale: At the beginning of sketching, the scale is too small, which makes many small parts difficult to identify, such as manhole covers, poles, etc., thus the whole sketch is a mess when drawing electronic drawings, which requires us to draw sketches with a moderate scale. Through this production practice, my personal experience is to draw a sketch according to the vision of the stand, and draw an eagle eye map on the next page or next to some special places.
3. elevation point: this point is not simply a question of elevation point, but a surveying and mapping standard or an industry standard. In the tender of Yunfu Municipal Bureau of Land and Resources, it is clearly stipulated in the "Elevation Notes" of "Topographic Element Survey" that "this survey and mapping will note elevation points according to the required density (generally not less than 5 annotation points per square)", but we have been making up the measurement of elevation points until the last few days, just because we have not carefully studied the big standards, which is a lesson.
Of course, there are still many shortcomings, such as slow adjustment, slow field mapping, slow indoor mapping, and no fixed format for data storage, which require our serious reflection.
Here, I'd like to thank Mr. Zhang, who has been with us for so many days, and also thank Mr. Yuan Gong and Mr. Sun from Hunan Jiaotong University for teaching us knowledge.