Applications

Making panoramic images and three-dimensional model of Hunan Express Highway

  • Time: 2012-09-03 17:35:04
  • Click: 7085

Project Background:

With the rapid development of China's highway construction, high-grade highways realize progressively GIS database management, which becomes more important on the management of road surface plate status, road appurtenances as well as road property etc. In order to be able to know the status of the road surface plates, ensure the smooth access of the highway, the management departments hope to get the real time topographic map and also three dimensional panorama image data with strong current tendency, so as to knowtimely and accurately the status of the road, search quickly the road and make maintenance plan.

Traditional GPS RTK and total station etc. are still used in express highway data collection at present. The work efficiency is low and there are more potential safety hazards. The results are single (2-D topographic map). Topcanproposes one set of digital topographic map surveying and panorama image collectionsolution. This solution is based on IP-S2 mobile measurement, not only provides the basis of conventional digital topographic maps, but also provides three-dimensional panoramic images to road management departments, so that the road management department is very convenient on the management of road surface plates, road ancillary facilities and road property.

Hunan expressway management project was aimed at the present status of Hunan express highway, adopted IP-S2 mobile measurement systemfor quick data collection and update, and established corresponding management information system. The project results were recognized and valued highly by the relevant departments.

 

Overall framework:

In order to realize database management, the highway management department required to survey and draw 1:2000 belt topographic map on both sides of the highway about 100 meters wide, and collectmore high precision 3D coordinates of the road surface (bridge floor), toll square and so on, as well as the 3D coordinates of all road appurtenances, such as telephone booths, vehicle monitor, milestone. For this reason, the express highway measurement proposed by us included conventional digital topographic mapping and the data collection required for GIS database.

After 140 kilometers of pilot production, the road sections surveyed by conventional GPS RTK and total station were measured again by IP-S2 system. The plain and height accuracy of two results were used for large quantity of data statistics. A variety of operating solutions were selected for comparison, trying to reduce the workload while meeting the accuracy requirements, improving efficiency. Combined with IP-S2 system technical characteristics, propose a more mature operating solution.

 

The entire operation process is shown in following figure:


 

Figure l operating flow diagram  

System function introduction:

IP-S2 mobile measurement system not only updates rapidly the existing topographic map, but also enriches the function of the original express highway management information system. The system is no longer a single managerial data from the two-dimensional plane, but realizes the management and search based on image. The main functions of the three-dimensional express highway management information system are:

Three-dimensional browsing function

Open the panoramicimage at any position and read the information on both sides of the express highway and road in 360-degree.The eye point of the user can move forward, backward, up and downin three-dimensional scene. And the user can switch to any position to see the image information, to see road signs, roadmarking and other information.

2 三维浏览功能(1  

Point cloud and 360-degree panorama image are overlapped in display, and linked with two-dimensional data, to view the panoramic map and point cloud of anyplace, and to realize high precision measurement based on point cloud for point, line and plane.

Figure 3 3D browsing function (2) - viewing clearlythe road signs on both sides and other information  



Three-dimensional measurement function  

Based on point cloud measurements, the management of express highway wheel track and car marks is more accurate.Measure directly the height, area and other information.

Figure 4 two-dimensional map is overlapped with driving route, point cloud and 360-degree panorama image

Figure 5 measurement function and signs management


Figure 6 area measurement overlapped with SHP drawing layers  

Collection and search functions  

Based on point cloud, collect the image of object and entry attribute, and output the result in the format readable by other GIS software.  

Figure 7 Data collection (vector and attributes) and database entry management


Figure 8 point cloud image of express highway  

Main results:

In this project, in addition to submitting the results of the highway management information system, we also need to update the topographic map of the entire express highway. After the point cloud image (Figure 7) collected and the photo is matched, we create quickly a line drawing. The absolute accuracy is within 10cm in the horizontal direction, within 15cm in vertical direction, meets and exceeds the requirements of 1:2000 topographic maps.

Figure 9 express highway DLG result drawing based on the point cloud image and photo  

System advantages:

Compared with the traditional work methods, the field operation in IP-S2 system needs only datum control measurements, and supplementary measurement on few ground objects not scanned. The overall field works are reduced by about 80%. As a lot of field works are moved to the office collection, the project work efficiency is increased by about one time.The lower cost of the work and efficiency increased can bring better economic and social benefits.

IP-S2 mobile measurement system, used for highway data collection projects, has many advantages, mainly in the following aspects:

l  Form a complete set of solution on express highway management. The express Highway management is faster and convenient;

l  IP-S2 meets fully the accuracy requirement of digital topographic surveying and mapping of express highway in different scales, and the express highway surface can identified clearly (such as slab joint and wheel track) etc. The photo and point cloud image can be collected at same time, so that the road condition is much clear.

l  Express highway surveying and mapping results are more rich and intuitive, and the results are diversified, no longer a simple belt topographic map. The panoramic photo can be used for making panoramic image on both sides of express highway. The view of express highway conditions is more vivid and can reflect the present status of the express highway in in many ways (such as road signs and milestones, etc.).

l  The field operation is easier, reducing surveyors'potential safety hazard;

l  Reducegreatly the operating cost and shorten the construction period, creatingbigger economic benefits.