Positional Accuracy Assessment of Orthophoto and Digital Elevation Model: A Case Study in Dire Dawa City, Ethiopia
| dc.contributor.advisor | Tulu, Besha (PhD) | |
| dc.contributor.author | Nathanael, Merkin | |
| dc.date.accessioned | 2021-09-22T04:09:44Z | |
| dc.date.accessioned | 2023-11-28T13:46:15Z | |
| dc.date.available | 2021-09-22T04:09:44Z | |
| dc.date.available | 2023-11-28T13:46:15Z | |
| dc.date.issued | 2021-09 | |
| dc.description.abstract | The quality of any geospatial data depends on its accuracy for mapping, design, analysis, and decision-making purposes. In this study, positional accuracy assessment was carried out with two datasets orthophoto and digital elevation model (DEM) generated from an aerial survey having 15cm ground sample distance using statistical analysis. Seven checkpoints were measured in the field using a static differential global positioning system technique Trimble 5800 global positioning system (GPS) and processed with Leica Geo-office (LGO) software and different online post-processing. Also, fifty-two parcel corners and road centerlines were selected and measured with real-time kinematic techniques for feature comparisons. The Easting and Northing coordinates from these points were compared with their corresponding positions extracted from orthophoto for horizontal accuracy. Seventy checkpoints were compared with their corresponding positions extracted from DEM for vertical accuracy. The accuracy of orthophoto evaluated with Static GPS measurement was root mean error (RMSE) of 12.90cm in Easting and 18.40cm in Northing and positional error of 22.5cm having horizontal accuracy of 38.9cm at 95% confidence level. The GPS coordinates of the parcel corner deviate from the corresponding coordinates of the orthophoto parcel corner having 26cm in the x-direction and 15cm in the y-direction. Therefore, it can be concluded that the accuracy of orthophoto map is within the national standard of error budget and has been used for different applications. The vertical accuracy results in RMSE of 4.06m, which shows that it does not meets the national standard of vertical data accuracy requirement, i.e., root mean error in z- direction (RMSEz) of ± 0.45m and American standards of photogrammetry and remote sensing (ASPRS) standard. Elevation deviation increases with slope increases from flat terrain characteristics to escarpment terrain characteristics. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/27960 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Orthophoto | en_US |
| dc.subject | Digital Elevation Model | en_US |
| dc.subject | Dire Dawa City, Ethiopia | en_US |
| dc.title | Positional Accuracy Assessment of Orthophoto and Digital Elevation Model: A Case Study in Dire Dawa City, Ethiopia | en_US |
| dc.type | Thesis | en_US |