Document Type : Research Paper

Authors

1 Assistant Professor of Geography and Urban Planning, Tabriz University, Tabriz, Iran

2 Master of Geography and Urban Planning, Tabriz University, Tabriz, Iran

Abstract

INTRODUCTION
Extraction and processing of various features with the help of aerial imagery reduces the time and financial costs associated with the use of ground mapping and the resulting human error. Advances in the field of aerial sensors in terms of spatial and spectral resolution with precise place and performance picking up altitude from the ground have led to the use of each part of information about terrestrial phenomena such as spectral and spatial characteristics Brought. Today, complementary data used to detect complications are Lidar data, the sensor of which is sent and received, and the electromagnetic spectrum in the near-infrared spectrum (in its aerial form) and joined the spectrum. Pays close infrared and green band (in space type).
 
DATA AND METHODS
Lidar data and spectral images were analyzed using different types of algorithms effective in landfill extraction to assess density. New layers of images were obtained in the form of raster from the study area, which was analyzed by performing slope extraction steps on flat and sloping surfaces. Buildings that were definitely not buildings were removed. The size and spectral characteristics of the missing structures were identified and the parcels were redistributed to extract the impermeable surfaces. Which led to the achievement of two levels of parcels and impenetrable points. The data set is related to the northern part of Bandar Anzali, which includes a vertical aerial photograph, irregular cloud points of the region with dense one to two points per square meter with an average point space of 0.69 square meters, and vertical aerial photograph with spatial resolution. It is 8 cm square.
 
RESULTS AND DISCUSSION
In this study, a different method for extracting buildings using airborne Lidar data and ultracam images was presented. The proposed system used geometric and spatial information of Lidar data and ultracam images, which included three general steps, in the first step; Lidar data were filtered and extracted using spectral clustering of buildings. In the second step; The obtained model was compared with the two-dimensional boundaries of buildings by the height threshold method. In the third step; After extraction, the first building boundaries were merged with the structures extracted by the checker algorithm. In the stage of separating terrestrial from non-terrestrial points, all points related to land were classified and extracted. The remaining points were classified as roof points, which were dealt with in the fault section of the buildings. All the functions used enabled the system to successfully extract the structures from the Lidar data.
 
CONCLUSION
The data for the first return points were subtracted from the data for the last return points and a fixed value was obtained which depended on the altitude accuracy of the difference between the two returns. In addition to the mentioned method, the clustering method was used during the research that each cluster belonged to a roof section so that the characteristics of each surface model could be easily determined.
Then, to complete the shape of the roof, the footprint of the building that was extracted was used. In fact, the borderlines and inner vertices extracted only part of the shape of the border. Other sections, such as vertical edges, were not detected due to intersection. This is due to the lack of front sampling. Finally, the items extracted through spectral clustering in eCoginition software and two-dimensional boundaries extracted from ENVI Lidar software, to increase the accuracy of land surface extraction (buildings) and make the area of ​​buildings studied in this data Were merged. As mentioned; After extraction, the primary building boundaries were merged with the structures extracted by the checker algorithm. In the section of buildings diagnostics, buildings with errors were discussed and the evaluation of the results showed that the system used has relatively reached the set goals and the methods used include the threshold method. Elevation, clustering, spectral method, and integration method were evaluated for each of the four blocks with error rates of 28%, 15%, and 0%, respectively, based on the area of ​​extracted tolls to the study area. The error of each building was first examined in general and then in detail, and it was found that aerial Lidar technology has an extraordinary ability to collect very right and dense samples of altitude measurements of cities and a new level of detail information can be Accurately extracted building density automatically and efficiently from aerial Lidar data. In 417 buildings that were surveyed and analyzed, the height of the buildings was achieved with high accuracy and all the buildings in the study area were extracted with a compact and organic density as well as scattered and planned.

Keywords

Main Subjects

  • سجادی، یوسف، صادقیان، سعید، پارسیان، سعید، 1394، استخراج ساختمان به کمک ادغام داده­های ابر طیفی و لیدار، پایان نامه کارشناسی ارشد، دانشکده مهندسی عمران نقشه برداری، دانشگاه تفرش، ص1-14.
  • سیف، عبدالله، محمودی، طیبه، 2014، سنجنده لیدار و کاربردهای آن، فصلنامه اطلاعات جغرافیایی(سپهر)، دوره بیست و سوم، شماره 89.، ص72-80.
  • محمدیاری، ف، ح، پورخباز، م، توکلی، ح، اقدر، 1393، تهیه نقشه پوشش گیاهی و پایش تغییرات آن با استفاده از تکنیک­های سنجش از دور و سامانه اطلاعات جغرافیایی(مطالعه موردی: شهرستان بهبهان)، فصلنامه اطلاعات جغرافیایی(سپهر)، ص 23-34.
  • مدیری، مهدی، 1378، مبانی و اصول دورکاوی، چاپ اول، انتشارات سازمان جغرافیایی نیروهای مسلح، ص302.
  • هژبری، بلال، صمدزادگان، فرهاد و حسین عارفی، 1393، بازسازی مدل ساختمان بر مبنای تلفیق ابر نقطه لیدار و تصویر هوایی، نشریه علمی-پژوهشی علوم و فنون نقشه برداری، دوره سوم، شماره 4، ص 1092-1067.
  • Alexander, Ernest R. (1993). Density measures: A review and analysis. Journal of Architectural and Planning Research 10(3), pp, 181-202.
  • M, C.S.Fraser. (2014). “Automatic Segmentation of Raw LIDAR Data for Extraction of Building Roofs,” Remote Sens, 6, 3716-3751.
  • Bailang Yu , Hongxing Liu ,Jianping Wu ,Yingjie Hu ,Li Zhang. (2010). “Automated derivation of urban building density information using airborne LiDAR data and object-based method”, jurnal Landscape and Urban Planning, pp. 10-15.
  • Burton, E. (2000). The Compact City: Just or Just Compact. A Preliminary Analysis, Urban Studies, 37 (11), pp, 1969-2001.
  • Chaouch, A., and Mari, J. L. (2006). 3D Land Seismic Surveys: Defiition of Geophysical Parameters Oil & Gas Science andTechnology – Rev. IFP , Vol. 61, No. 5, pp, 611- 630.
  • Cuthbert, A. R. (2006) the form of Cities, Carlton, Victoria: John Wiley, pp, 328.
  • Dehvari, A., Heck, R.J. (2012). Removing non-ground points from automated photo-based DEM and evaluation of its accuracy with LiDAR DEM, Computers & Geosciences, 43, pp, 108-117.
  • Dave, Seema. (2011). Neighbourhood Density and Social Sustainability in Cities of Developing Countries, Wiley Online Library, Sust. Dev 19, pp, 189–205 .
  • Farouh, H.E., El Din, H.S., Shalaby, A., & Elariane, S.A. (2015). Principles of urban quality of life for a neighborhood. HBRC Journal, 9, pp, 86-92.
  • Forsyth, A., Oakes, J. M., Schmitz, K. H. & Hearst, M. (2007). Does Residential Density‌ Increase Walking and Other Physical Activity, Urban Studies, Vol. 44 (4),pp. 679-‌697.‌
  • Montgomery, A. Saunders, A and Chortis, J. (2003). Density considerations in managing residential land provision in Perth, Western Australia, Presented at the State of Australian Cities Conference, Perth, December, pp, 3-5 .
  • Polat, N., Uysal, M., Toprak, A.S. (2015). An investigation of DEM generation process based on LiDAR data filtering, decimation, and interpolation methods for an urban area, Measurement 75, pp, 50 - 56.
  • Sivam, A., Karuppannan, S. and Davis, M. C. (2011). Stakeholders' Perception of Residential Density: A Case Study of Adelaide, Journal of Housing and the Built Environmen, pp, 473-494.
  • Sivam, A. and Karuppannan, S. (2012). Density Design and Sustainable Residential Development, Presented at the European Network for Housing Research Conference 2009, 28 June to 1 July, Prague, Czech Republic, pp, 253-276.
  • Sithole, G., and Vosselman, G. (2004). Experimental comparison of filter algorithms for bare-Earth extraction from airborne laser scanning point clouds, ISPRS Journal of Photogrammetry & Remote Sensing 59,pp, 85 - 101.
  • Vosselman, G. and Maas, H.G. eds. (2010). Airborne and terrestrial laser scanning, Whittles Publishing, pp, 56-63.