Evaluation of the Use of Inertial Platform for the Generation of Cartography

This study aims to analyze the quality of positioning orthophoto generated through the technique of direct georeferencing using metric digital camera system coupled to the laser system, and both systems were aided inertial navigation platform. For this, we compared the coordinates obtained in 16 control points collected in the field with dual-frequency GNSS （global navigation satellite system） receiver with those obtained in the orthophoto, flight conducted in June 2009 on the campus of the State University of Campinas--UNICAMP, using a medium format digital camera and laser system, with which we obtained images with a spatial resolution of 0.15 m. Taking into account the pattern accuracy cartographic used in Brazil, it is concluded that the products produced have a standard accuracy ＂A＂ to 1：2,000 scale, which represents the best quality level, both for planimetric as for altimetry, and that the procedure reached results consistent with cartographic products in 1：2,000 scale, representing a reduction of steps in the mapping process, necessary for the preparation of cartographic databases with reduction of time for preparation of design basis large civil engineering projects, such as roads, railways, studies of urban road systems, power plants and other infrastructure systems needed to develop the country.

Land Parcel Land Use History as a Key to Site Selectionfor Documenting Soil Contamination Risk: a Case Study from Australian Suburbia

In that orcharding in early to mid twentieth century southeastern Australia involved use of certain heavy metal and As compounds in regular pest control spray procedures, some interest attaches to the possibility that these landparcels are underlain by soils with above background Cu, Pb and As levels. Interpretation of Land cover changes allowed land parcels previously occupied by orchards to be identified in the 1950s through time series air photos. A comparison of soil analysis results referring to soil samples from control sites, and from land parcels formerly occupied by orchardists, shows that contamination (above background) levels of cations in the pesticides can be found in the top 6 cm of former orchard soils. It is clear that digital spatial data handling and culturally informed air photo interpretation has a place in soil contamination studies, land use planning (with particular reference to re development) and in administration of public health.

Automatic Correction of DEM Surface Errors

The automation of extracting planner surfaces is a main field of research in digital photogrammetry. These surfaces are essential to generate three dimensional GIS databases. Surfaces are usually determined from either DEMs or images. Each dataset provides a different type of information. Thus, the combination of the two datasets should enhance the surface reconstruction process. This paper presents a new technique for generating 3D surfaces by combining both correlation-based DEMs and aerial images. The process starts by discriminating DEM points that represent planner surfaces using local statistics of neighboring elevations and intensities and point elevations. A segmented orthophoto is then used to group these points into different regions. The elevations of the points in each region are fed into a least squares adjustment model to compute the best-fit planner surface parameters. Refinement of surface borders is then performed using a region growing algorithm. The RMSE for five test sites showed a spatial accuracy of 5 - 8 cm.

Fully automatic DOM generation method based on optical flow field dense image matching

Automatic Digital Orthophoto Map(DOM)generation plays an important role in many downstream works such as land use and cover detection,urban planning,and disaster assessment.Existing DOM generation methods can generate promising results but always need ground object filtered DEM generation before otho-rectification;this can consume much time and produce building facade contained results.To address this problem,a pixel-by-pixel digital differential rectification-based automatic DOM generation method is proposed in this paper.Firstly,3D point clouds with texture are generated by dense image matching based on an optical flow field for a stereo pair of images,respectively.Then,the grayscale of the digital differential rectification image is extracted directly from the point clouds element by element according to the nearest neighbor method for matched points.Subsequently,the elevation is repaired grid-by-grid using the multi-layer Locally Refined B-spline(LR-B)interpolation method with triangular mesh constraint for the point clouds void area,and the grayscale is obtained by the indirect scheme of digital differential rectification to generate the pixel-by-pixel digital differentially rectified image of a single image slice.Finally,a seamline network is automatically searched using a disparity map optimization algorithm,and DOM is smartly mosaicked.The qualitative and quantitative experimental results on three datasets were produced and evaluated,which confirmed the feasibility of the proposed method,and the DOM accuracy can reach 1 Ground Sample Distance(GSD)level.The comparison experiment with the state-of-the-art commercial softwares showed that the proposed method generated DOM has a better visual effect on building boundaries and roof completeness with comparable accuracy and computational efficiency.