Landslide monitoring is a crucial tool for the prevention of hazards. It is often the only solution for the survey and the early-warning of large landslides cannot be stabilized. The objective of present study is to use a low-cost image system to monitor the active landslides. We adopted the direct linear transformation (DLT) method in close range digitalphotogrammetry to measure terrain of landslide at the Huoyen Shan, Miaoli of central Taiwan and to compare measured results with e-GPS. The results revealed that the relative error in surface area was approximately 1.7% as comparing the photogrammetry with DLT method and e-GPS measurement. It showed that the close range digitalphotogrammetry with DLT method had the availability and capability to measure the landslides. The same methodology was then applied to measure the terrain before landslide and after landslide in the study area. The digital terrain model (DTM) was established and then was used to calculate the volume of the terrain before landslide and after landslide. The volume difference before and after landslides was 994.16 m 3 .
This paper describes in detail the dense matcher developed since years by Vexcel Imaging in Graz for Microsoft’s Bing Maps project. This dense matcher was exclusively developed for and used by Microsoft for the production of the 3D city models of Virtual Earth. It will now be made available to the public with the UltraMap software release mid-2012. That represents a revolutionary step in digitalphotogrammetry. The dense matcher generates digital surface models (DSM) and digital terrain models (DTM) automatically out of a set of overlapping UltraCam images. The models have an outstanding point density of several hundred points per square meter and sub-pixel accuracy and are generated automatically. The dense matcher consists of two steps. The first step rectifies overlapping image areas to speed up the dense image matching process. This rectification step ensures a very efficient processing and detects occluded areas by applying a back-matching step. In this dense image matching process a cost function consisting of a matching score as well as a smoothness term is minimized. In the second step the resulting range image patches are fused into a DSM by optimizing a global cost function. The whole process is optimized for multi-core CPUs and optionally uses GPUs if available. UltraMap 3.0 features also an additional step which is presented in this paper, a complete automated true-ortho and ortho workflow. For this, the UltraCam images are combined with the DSM or DTM in an automated rectification step and that results in high quality true-ortho or ortho images as a result of a highly automated workflow. The paper presents the new workflow and first results.
2. GLACIER MEASUREMENT-PREVIOUS WORK There is a long history of measuring glacial surfaces using remote sensing techniques. Baltsavias et al, (2001) provides a useful review including space-borne sensors, aerial photogrammetry and airborne laser and optical sensors. Space- borne sensors are suitable for iceberg tracking and glacier mapping or glacial mapping at small-scale but are unsuitable if a DEM is required. Airborne laser scanning and aerial photogrammetry have been successfully used for medium scale tasks. However, difficulties arise in airborne photogrammetry within areas exhibiting strong shadows, or where there are large expanses of white ice/snow, or smooth snow (Baltsavias et al., 2001; Fox and Gooch, 2001). Such areas cause gross errors in DEMs generated automatically using traditional area correlation techniques. Airborne laser sensors perform better on texture-less snow and ice areas, but blunders are likely in regions exhibiting poor reflectivity due to debris or rock (Baltsavias et al., 2001). Despite this, both airborne laser scanning and digitalphotogrammetry appear to be suitable for medium-scale cryospheric applications, retrieving roughness at the decimetre scale (Baltsavias et al. 2001; Nolin et al., 2002; Hopkinson and Demuth, 2006; Höfle et al., 2007; Rees and Arnold, 2006). The airborne perspective remains inappropriate for aerodynamic applications where a centimetre or millimetre scale is necessary.
European Commission funded project entitled: “Support to the mapping and certification capacitв of the Agencв of Land Management, Geodesв and Cartographв” in Tajikistan was run by FINNMAP FM-International and Human Dynamics from Nov. 2006 to June 2011. The Agency of Land Management, Geodesy and Cartography is the state agency responsible for development, implementation, monitoring and evaluation of state policies on land tenure and land management, including the on-going land reform and registration of land use rights. The specific objective was to support and strengthen the professional capacity of the “Faгo” Institute in the field of satellite geodesв, digit al photogrammetry, advanced digital satellite image processing of high resolution satellite data and digital cartography. Lectures and on-the- job trainings for the personnel of “Faгo” and Agencв in satellite geodesy, digitalphotogrammetry, cartography and the use of high resolution satellite data for cadastral mapping have been organized. Standards and Quality control system for all data and products have been elaborated and implemented in the production line. Technical expertise and trainings in geodesy , photogrammetrв and satellite image processing to the World Bank project “Land Registration and Cadastre Sвstem for Sustainable Agriculture” has also been completed in Tajikistan. The new map projection was chosen and the new unclassified geodetic network has been established for all of the country in which all agricultural parcel boundaries are being mapped. IKONOS, QuickBird and WorldView1 panchromatic data have been used for orthophoto generation. Average accuracy of space triangulation of non-standard (long up to 90km) satellite images of QuickBird Pan and IKONOS Pan on ICPs: RMSEx=0.5m and RMSEy=0.5m have been achieved. Accuracy of digital orthophoto map is RMSExy=1.0m. More then two and half thousands of digital orthophoto map sheets in the scale of 1:5000 with pixel siгe 0.5m have been produced so far bв the “Faгo” Institute in Tajikistan on the basis of technologв elaborated in the framework of this project. Digital cadastral maps are produced in “Faгo” and Cadastral Regional Centers in Tajikistan using ArcMap software. These digital orthophotomaps will also be used for digital mapping of water resources and other needs of the country.
This paper will focus on these issues and present experiences gathered from a Master Thesis on “E-learning in DigitalPhotogrammetry and Remote Sensing for Non Experts using Moodle” at HFT Stuttgart in co-operation with a software vendor and a reseller and experiences from a current European Tempus IV project GIDEC (Geographic information technology for sustainable development in Eastern neighouring countries). The aim of this research is to provide an overview on available methods and tools and classify and judge their feasibility for the above mentioned scenarios. A more detailed description is given on the development of e-learning applications for DigitalPhotogrammetry and Remote Sensing using the open source package Moodle as platform. A first item covers the experiences from setting up and handling of Moodle for non-experts. The major emphasis is then on developing and analyzing some few case studies for lectures, exercises, and software training in the fields of DigitalPhotogrammetry and Remote Sensing. Feedback from students and company staff will be evaluated and incorporated in an improved design and sample implementation. A further focus is on free software and tools to allow an easy integration of dedicated methods as audio and video flashes, quizzes for self evaluation, dynamic training, web-conference, etc. into the e-learning platform. The overall objective is to evaluate on how far it is currently possibly to allow the non-experts from academic and non academic sectors to get the initial experience and knowledge in DigitalPhotogrammetry and Remote Sensing in a modern, flexible and economic way. The time and the skills required for developing web-based materials will thus be investigated in more detail. Additionally, the quality of the developed e-learning application will be assessed based on a list of quality criteria developed.
The integrated digital survey in the data acquisition phase is configurated as interaction and integration of three distinct methods: topographic, laser scanning, photogrammetry. In this particular case it was considered not significant the application of the topography, and much has been done on the integration of data acquired by the 3d scanner and by digitalphotogrammetry. It has been verified as the use of the scanner, that based its technology on the principles of the total station topographic, in practice tends to converge with photogrammetry from which to borrow some well-established methodologies. Among these is the importance given to the acquisition project of data for the proper evaluation of the quality of the product obtained (Paris, 2010).
With the change into digitalphotogrammetry workflows and the new basic approaches, deduced from the computer vision technologies, the aerial photos gained from aerial surveys have an increasing importance for a variety of applications. The quality demands have increased and the currency cycles were shortened parallel. These new use cases strengthen the need for reliable sensor calibration. Not only the geometric calibration is required meanwhile the radiometric calibration as well is used, for example in raster-based classification processes.
In this regard, the most drastic factors in choosing the documentation technique of Kharraqan Tower were the limited budget, the location of the building, which was placed in an almost remote region, and the limitation of time for field working. Therefore, the least possible dependency to expensive complex equipment with limitation in accessibility was the considered factor in selecting the documentation method. According to what was mentioned above, different methods were studied to choose one that fits better with project facilities. First, since the building has curved surfaces; hand measuring could not be the right selection, as it cannot reach high accuracy. Besides, this technique needs more time to perform field working and reach the result. Other techniques such as surveying with the help of total station or laser scanner were expensive to apply according to the project's budget; and in case of using total station, the fieldwork would be time consuming. Besides, considering the architectural features of Kharraqan Tower, as it possesses valuable ornamental brick work, a technique should be applied to record precisely all the data of surface texturing. This point could not be achieved by any of the mentioned methods. Accordingly, image-based techniques, which can record textural information of the surface, were recognized as the proper methods. In addition, image-based methods can give us a three dimensional model of the object using images taken even by an amateur digital camera. This reduces the amount of costs needed for documentation process. Finally, considering all the above factors, close range digitalphotogrammetry was selected to make the project, since it still remains the most complete, economical, portable, flexible and
TanDEM-X mission has been acquiring InSAR data to produce high resolution global DEM with greater vertical accuracy since 2010. In this study, TanDEM-X CoSSC data were processed to produce DEMs at 6 m spatial resolution for two test areas of India. The generated DEMs were compared with DEMs available from airborne LiDAR, photogrammetry, SRTM and ICESat elevation point data. The first test site is in Bihar state of India with almost flat terrain and sparse vegetation cover and the second test site is around Godavari river in Andhra Pradesh (A.P.) state of India with flat to moderate hilly terrain. The quality of the DEMs in these two test sites has been specified in terms of most widely used accuracy measures viz. mean, standard deviation, skew and RMSE. The TanDEM-X DEM over Bihar test area gives 5.0 m RMSE by taking airborne LiDAR data as reference. With ICESat elevation data available at 9000 point locations, RMSE of 5.9 m is obtained. Similarly, TanDEM-X DEM for Godavari area was compared with high resolution aerial photogrammetric DEM and SRTM DEM and found RMSE of 5.3 m and 7.5 m respectively. When compared with ICESat elevation data at several point location and also the same point locations of photogrammetric DEM and SRTM, the RMS errors are 4.1 m, 3.5 m and 4.3 m respectively. DEMs were also compared for open-pit coal mining area where elevation changes from -147 m to 189 m. X- and Y-profiles of all DEMs were also compared to see their trend and differences.
In recent years several pieces of “shape from motion” (SfM) software based on computer vision technology have been often utilized in UAV photogrammetry. A few papers (Gini, et al. , 2013, Greiwe, et al., 2013) to evaluate the potential of UAV photogrammetry with SfM software were presented at the second UAV-g conference held in Rostock, Germany in September 2013. The papers indicated that SfM software is a powerful tool in UAV photogrammetry. The utilization of SfM software in UAV photogrammetry has prompted amateurs to utilize an UAV for 3D measurement.
Mapping hydrological pathways by which water moves over and through the Earth surface is essential for explaining hydrologi- cal, geomorphological, ecological and geochemical phenomena (Hyv¨aluoma et al., 2013; Bevington et al., 2016). Precise and detailed representations of terrain are needed to accurately pre- dict overland flow. Therefore the acquisition of high resolution digital elevation data is necessary for accurately mapping over- land flow paths (Leit˜ao et al., 2015). Lidar – a technology that measures the distance to a target based upon the travel time of reflected light – is still at the forefront of high-resolution 3D data collection methods (Hodgetts, 2013). Novel methods for photo based 3D surface reconstruction, however, have opened a new pathway for developing solutions to affordably and efficiently generate very high resolution digital terrain models. Photogram- metric techniques have long been used to derive topographic data from analogue imagery such as stereo aerial photographs. Re- cent advances in computer vision computer algorithms coupled with the availability and affordability of digital cameras, how- ever, have lead to dramatic improvements in the collection and processing of terrain data using photogrammetry. The novel pho- togrammetric approach called Structure-from-Motion (SfM) en- ables fully automatic generation of high resolution digital terrain models using multi-view stereo techniques to derive 3D data from imagery taken with consumer grade cameras. This approach can be used to examine objects captured with terrestrial photographs as well as aerial imagery (Bemis et al., 2014). The rising number of applications and innovations is driven by the increasing acces- sibility of Unmanned Aerial Systems (UAS) technology. Until recently, most UAS applications were military. In the last decade, however, the emerging market for small (sUAS), light and easy to use systems led to UAS applications in industry, research and entertainment. Geoscientists have taken advantage of the integra- tion of sUAS and the SfM approach; numerous geoscience stud- ies have demonstrated the relevance, cost-effectiveness and effi-
Photogrammetry can help in measuring volume collapsed during landslides. This study was conducted to determine how effective the use of UAV-Photogrammetry in measuring the amount of land that collapsed. Compared with the terrestrial methode. This research resulted orthophoto map landslides, as well as counting the number of collapsed volume. The amount of volume obtained by UAV-Photogrammetry methode is 10527.032 m³. as a comparison, the volume calculation obtained by terrestrial methode is 11491.708 m³ . Different volume is 964 676 m³. In this case the data retrieval process done by UAV needs less time and human resources than terrestrial.
Salah satu jenis sensor pada kamera digital adalah Charge Coupled Device (CCD). CCD adalah suatu alat pencitraan untuk menkonversikan cahaya menjadi arus elektrik yang proporsional (analog). Sebuah Charge Coupled Device (CCD) memiliki lapisan-lapisan filter yang membagi spektrum warna menjadi warna merah, hijau, biru agar bisa diproses secara digital oleh kamera. Ada dua macam jenis CCD, yaitu rangkaian linier yang digunakan dalam scanner datar, alat pengcopy digital dan Scanner Graphic Arts; serta rangkaian datar yang dipakai dalam comcorders, kamera video tidak bergerak, dan kamera-kamera digital. Setiap pixel didalam sensor kamera digital terdiri dari photodiode yang sensitif terhadap cahaya yang mampu mengukur tingkat brightness dari cahaya itu sendiri. Karena photodiode adalah device monokrom, maka tidak mungkin sensor mengenali perbedaan dari setiap panjang gelombang cahaya yang diterima.
The automatic detection and reconstruction of roads has been an important topic of research in Photogrammetry and Remote Sens- ing for several decades. Considerable progress has been made, but the problem has not been finally solved. The EuroSDR test on road extraction has shown that road extraction methods are ma- ture and reliable under favourable conditions, in particular in ru- ral areas, but they are far from being practically relevant in more challenging environments as they exist in urban or suburban ar- eas (Mayer et al., 2006). One of the main reasons for failure of road extraction algorithms in that test was the existence of cross- roads, due to the fact that model assumptions about roads (e.g., the existence of parallel edges delineating a road) are hurt there. For this reason, specific models for the extraction of crossroads from images have been developed. (Barsi and Heipke, 2003) used neuronal networks for a supervised per-pixel classification of greyscale orthophotos in order to detect areas corresponding to crossroads, combining radiometric and geometric features. How- ever, only examples for rural areas were shown. (Ravanbakhsh et al., 2008b, Ravanbakhsh et al., 2008a) used a model based on snakes to delineate outlines of road surfaces at crossroads, includ- ing the delineation of traffic islands. The main reasons for failure of that method were occlusion of the road surface by cars and a complex 3D geometry, e.g. at motorway interchanges. Occlu- sions were also a major problem in (Grote et al., 2012), which also gives an overview over other current road detection tech- niques. The problem of occlusion by cars could be overcome if the position of cars were known in the images.
Seringkali pengguna teknologi digital tidak peduli dengan etiket penggunaan teknologi, tetapi langsung menggunakan produk tanpa mengetahui aturan serta tata krama penggunaannya. Atau sudah mengetahui tetapi menganggap etiket digital tidak terlalu penting untuk diperhatikan. Seringkali para pengguna digital melupakan bahwa walaupun dalam dunia digital para pengguna tidak saling bertatap muka, tetapi perlu diperhatikan bahwa di balik setiap akun, di balik setiap posting forum, terdapat individu lainnya yang dapat tersinggung jika Kamu melanggar tata krama.
Kebutuhan suatu informasi pada era digital saat ini cukup tinggi dan akan semakin tinggi, terutama informasi dari internet. Tingginya kebutuhan akan informasi tersebut memunculkan pelbagai macam mesin pelacak/pelacak/ penelusur informasi, namun setiap mesin pelacak memiliki algoritma yang berbeda antara satu dan yang lain. Saat ini Google merupakan mesin penelusur paling diminati, selain kecepatan penelusuran, juga hasil yang ditelusur dinilai hampir memenuhi yang diinginkan pengguna. Pada kegiatan belajar ini, kita akan mempelajari cara penggunaan kata kunci pada mesin pelacak sehingga informasi yang hendak dicari akan sesuai dengan apa yang dibutuhkan. Setelah mendapatkan halaman yang dianggap sesuai, kita akan mempelajari bagaimana menyimpan halaman tersebut untuk diolah kemudian menggunakan perangkat lunak pengolah kata, angka, maupun penyaji presentasi yang telah kita pelajari pada kegiatan belajar sebelumnya.
Kebutuhan setiap orang terhadap informasi digital mengakibatkan arus informasi yang semakin kuat. Ketika dahulu buku menjadi sumber utama untuk pencarian informasi, kini mesin pelacak/search engine menjadi alat yang paling diKamulkan untuk melacak suatu informasi. Penggunaan kata kunci yang tepat pada mesin pelacak sangat diperlukan agar dapat menemukan informasi yang dimaksud dengan cepat dan tepat.