Loading...
Please wait, while we are loading the content...
Similar Documents
Slope generation using ArcGIS Model Builder a tool to check the accuracy of Digital Elevation Model ( DEM ) generated through photogrammetric block
| Content Provider | Semantic Scholar |
|---|---|
| Author | Parida, P. K. Sanabada, M. K. Mohapatra, Amit Kumar |
| Copyright Year | 2013 |
| Abstract | The question of Digital Elevation Model (DEM) accuracy and interdependency of the height errors is closely connected with the question of the surface definition. In practice, the terrain surface is always an artificial surface that is consciously simplified and smoothed in order to obtain appealing or even usable products from the DEM. Thus DEM accuracy has to be defined with respect to the needs of the specific application. The accuracy of slope and all associated values is one important derived product from the DEM. It depends first of all in the height accuracy and on the resolution of DEM. But it also depends on the systematic parts of the height errors due to presence of systematic distribution like habitation, vegetation etc. Height errors normally distributed for a larger data set, but usually they show high local correlations. The consequence of ignoring systematic errors is an often unrealistic (i.e. too pessimistic for slope values) estimation of the quality of the derived data. DEMs with high cartographic quality (high resolution) show maximum correlation of errors with neighborhood pixels. DEM generation using digital stereo-data in a digital photogrammetric environment by building a photogrammetric block with a RMS value adjusted to half of the pixel value of the satellite data/aerial data being used for the purpose gives a good quality product but it cannot be used directly for any product generation like ortho-image/photo without editing the same. Editing of DEM requires skilled professional involvement and extensive time. Verification of DEM quality after editing by visualization in 3D mode is also more pain staking job. Thus slope generation and representation of slope in a continuous color range with percentage mode or degree mode helps to identify the error associated with DEM. There are other methods like generation of drainage/stream from the DEM, which can be superimposed with the existing drainage layer to verify the accuracy of DEM. In this paper it has been tried to prepare a tool using model builder of ArcGIS Ver.10.1, which was used to test the accuracy of DEM in a real time production mode project i.e. Space Based Information System for Decentralized Planning (SIS-DP) involving Cartosat-1 stereo pairs for Odisha state. This tool was very much helpful to check the accuracy of scene wise DEM generation in a real time production mode project as well as mosaicking of the DEMs up to the district/state level. E mail ID: 1 pkparida@yahoo.com, 2 m_sanabada@yahoo.co.in, 3 amiya55@sify.com 14 Esri India User Conference 2 Page 2 of 8 Introduction Several applications in earth and environmental sciences need information derived from the height data of the Digital Elevation Model (DEM). There is a special need for slope values, slope vectors and slope directions especially in water management, hydrology and environmental disaster prevention. A lot of research work has been done to define the accuracy of the DEM in terms of height errors, e.g. (Ackermann 1979), (Zhang, 1988), (Theobald, 1989). Frequently this is done by describing the root mean square (RMS) error of single DEM points. Another more sophisticated approach in order to obtain information to obtain the quality of DEMs is the use of Fourier Transformation (Makarovik, 1972), which especially allows to take into regard the periodical characteristics of height errors. But dealing with online projects having 300 and more DEM scenes (27.5k.m X 27.5k.m) with a resolution of 10mx10mt, it is really a difficult job to test the accuracy of DEM scenes by applying mathematical algorithms such as Fourier Transformation. Practically the quality checking scientist/engineer has to verify the scene by visualizing the sharp change in height which can be easily done by converting it into slope and applying a color scheme to visualize the slope in percentage or degree unit. The sharp change in height values in DEM can be detected and the DEM can be again edited in 3D environment to rectify the height errors. In order to simplify the task, ARC GIS ver.10.1 model builder has been utilized to create a tool to generate the slope, which took care of carrying out the job easily. In this study, DEM was generated for the entire state of Odisha under a National level Project i.e. Space Based Information Support for Decentralized Planning (SIS-DP) using a controlled photogrammetric block of Cartosat-1 stereo digital data. Objective The objective of the study is to prepare a single photogrammetric block model of the State Odisha to generate a seamless Digital Elevation Model and Ortho image. Study area The entire State of Odisha bounded by the latitude and longitude as follows. 17 0 31 ’ N to 22 0 31 ’ N 81 0 31‘E to 87 0 30’ E |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.esriindia.com/~/media/esri-india/files/pdfs/events/uc2013/proceedings/papers/UCP071.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
