Small-format Aerial Photography Research Articles

THE STUDY OF ANTHROPOGENIC DISTURBANCE ON GEOPEDOGENETIC PROCESS AT THE LOWER SLOPE OF MT. UNGARAN, INDONESIA

Volcanic rocks mining activity will undoubtedly remove vegetation cover and cause the physical environment changes. Revegetation effort as part of land rehabilitation program then often found many obstacles because it was mostly conducted without adequate knowledge of detailed morphology and soil characteristics at the post-mining area. This study investigates the geopedogenetic changes, including land surface morphology, recent geomorphic processes, and soil properties caused by andesite rocks exploitation at the northern flank of Mt. Ungaran, Central Java Province of Indonesia. A digital terrain model was firstly generated from small format aerial photography acquired by an unmanned aerial vehicle (UAV) to identify the surface morphology changes due to the mining. Soil observation on field and laboratory test were conducted from samples at the affected and unaffected mining areas in order to analyse the changes on pysiochemical properties. This research exhibits that the mining activities have altered a single convex hill into a complex land surface morphology consisting of sloping zone, basins and flat area. Human disturbance on pedogenetic process at the mining area are in the form of parent material alteration that make them return to the early stage of soil development and top soil reduction that modify its genetic horizons. In addition, the changes on surface morphology and the absence of vegetation cover right after the mining ends also triggered new geomorphic processes in the form of incision and deposition on slopes and basin respectively. The finer deposit layers then become a new parent material at the basin zone. Soil laboratory data demonstrate that the affected soils tend to have a high level of base saturation, but lower C-organic and N-total levels, which result in a less favourable environment for supporting vegetation growth. A precise surface morphology design, extra soil surface protection and organic matter enhancement could be wise recommendations for land managers to control soil incision and support vegetation growth at the andesite post-mining area.

Horizontal And Vertical Measurement of UAV Aerial Photo Exposures Results In The Senowo River Area, Krinjing Village, of The Merapi Volcano, Magelang District of Central Java Indonesia

This study aims to examine the acquisition of small format aerial photography with UAVs and to display orthophoto data for elevation data extraction. The research area was conducted in a part of the Senowo River north of Merapi volcano in Central Java. The Photogrammetric methods using UAV planes need to be done for horizontal and vertical accuracy studies. This accuracy study was carried out by referring to the height of the flying plane and the geometry accuracy of the Rupa Bumi Indonesia (RB I= Standardized Topographic Map of Indonesia) map. The results of this study are accuracy testing based on the comparison of the coordinates of the test points with the results of aerial photo processing obtained by horizontal RMSE of 0.034 meter and vertical RMSE of 0.598 meter with an accuracy of 98%. RMSE value is used to determine the value of Circural Error 90 (CE90) and Linear Error (LE90). The value obtained by CE90 is 0.25 meter and the LE90 value is 0.99 meter. The accuracy of the orthophoto map that can be made is a scale of 1: 2,500 in class 1st for horizontal accuracy and a scale of 1: 5,000 in class 1st for vertical accuracy. Therefore, in the selection of optimal scale orthophoto maps, the recommended scale is 1: 5,000.* PT. Wijaya Karya Jakarta Indonesia**Assc. Prof. of the Geography Department of Social Science Faculty UM

The Use of Small Format Air Photos for Mapping Land Cover Changes in Gumuk Pasir Parangtritis Core-Zone, 2015-2019

Gumuk Pasir Parangtritis is one of the potentials of the coastal area of ​​Parangtritis village in Yogyakarta, with several important roles for the coastal ecosystem and its surroundings, such as ecology, disaster, tourism, economy, and aquifer reserves. However, behind this important role, the existence of sandbanks is increasingly threatened from year to year because the area of ​​sand cover continues to decline, especially in the core zone. Therefore, regular and effective mapping and monitoring efforts are needed. This study aims to a) conduct land cover mapping using the Geographic Object Based Image Analysis (GEOBIA) method in the 2015-2019 timeframe; b) analyze changes in land cover in the core zone of sandbanks during 2015-2019; and c) evaluate the results of restoration of sand dune core zone in terms of land cover changes that have occurred until 2019. Small format aerial photographs (FUFK) are the data used in this study while the mapping method used is rule-based classification. The land cover of the sand dune core zone in 2015 included buildings, vegetation, sand, roads and ponds, while in 2019 it was in the form of buildings, vegetation, sand, and roads. Based on the classification results in the two years, it can be seen that there are changes in land cover (including area) through the cross-section of the two classification results. Some of the factors include the number of land use changes, the amount of vegetation, and sand mining. Furthermore, this change can be used as a basis for evaluating the success of the restoration efforts of the Gumuk Pasir Parangtritis core zone to date. The results of the evaluation show that the restoration carried out so far has not had much impact so it can be said that it has not been successful, because the area of ​​sand cover has actually decreased a lot (from 528,680 m2 to 344,347 m2), while the land cover in the form of vegetation and buildings has increased in size (from 869,341 m2 to 1,037,879 m2 for vegetation cover and an area of ​​4,674 m2 to 22,953 m2 for buildings).

Geometric Accuracy Comparison of Shorelines Derived from Multitemporal Sentinel-2A Imagery with Various Image Spectral Transformations (Case Study: Marine Deposition Coasts in Bantul Regency, Yogyakarta, Indonesia)

Shoreline extraction from Landsat imagery is limited to 30m spatial resolution. The presence of Sentinel-2A imagery opens up opportunities for shoreline extraction for larger-scale mapping; thus, it is necessary to investigate the capability and limitations of various spectral transformations in mapping multitemporal shoreline positions. This study presents a methodology for processing Sentinel-2A imagery and methods for semi-automatic shoreline extraction. Experiments were carried out on marine deposition coasts as the coastal physical typology developing on most Indonesian coasts. The 20m Sentinel-2A imagery data acquired in 2015 until 2020 were compared with several spectral transformation methods: Automated Water Extraction Index Non-Shadow (AWEInsh), Automated Water Extraction Index Shadow (AWEIsh), Modified Normalized Difference Water Index (MNDWI), Normalized Difference Water Index (NDWI), Band Ratio (B3/B11), and Single Band (B11). The use of multitemporal imagery aims to test image and method consistencies in extracting shorelines accurately. The image acquisition time for each year was selected by taking into account cloud cover, land-sea contrast boundary (delimited with Otsu’s image thresholding algorithm), and data availability. The accuracy was assessed with small-format aerial photographs of 0.3m spatial resolution. The results indicated that MNDWI produced shorelines with RMSE ranging from 32 to 64 m, which meets the class-3 standard for 1: 50,000 scale maps per the Indonesian Geospatial Information Agency’s (Badan Informasi Geospasial, BIG) Regulation Number 6 of 2018. Therefore, 20m Sentinel-2A can be used as a data source in rapid shoreline extraction. Several factors contributing to RMSE that is 3 to 6 times greater than the spatial resolution of Sentinel-2A images include cloud cover, mixed pixels, foam, and tidal bias, creating data uncertainty values ranging from 28 to 45 m.

Using Remote Sensing to Monitor Cattail Invasion, Cheyenne Bottoms Preserve, Kansas

Cattail (Typha sp.) has become invasive since the mid-twentieth century in the central Great Plains region. Our long-term study site is the Cheyenne Bottoms Preserve marsh-pool complex, which is owned and managed by The Nature Conservancy (TNC). We employed various types of remote sensing and made ground observations, which we have conducted during the growing season every year since 2002. The goal has been to assist TNC management for cattail monitoring and control based on a pictorial and qualitative approach. During the past two decades, TNC was successful on two occasions in slowing or turning back cattail invasion of its marsh-pool complex. Both involved favorable combinations of climatic events and human actions. Surviving cattail is able to revive quickly and expand rapidly by clonal growth during wet periods, although prolonged high water of floods may arrest cattail growth. Under such variable and dynamic conditions, cattail expansion may regain or surpass previous limits in less than a decade. The long sequence of annual and multi-seasonal small-format aerial photography has proven invaluable for planning habitat work at Cheyenne Bottoms Preserve.

Non-destructive Measurement Methods of Sugarcane Canopy using Drone Technology

Destructive methods in the field of leaf area measurement are not effective for predicting plant growth. The development of Unmanned Aerial Vehicle (UAV) and digital camera sensors makes it easier to obtain Small Format Aerial Photography (SFAP) data. Nondestructive sugarcane (Saccharum officinarum) cutting using UAV technology is more effective than destructive methods. This study aims to determine the width of the tree canopy using Small-Format Aerial Photography Near-Infrared (NIR). The research stage includes a preliminary survey of sugarcane plantations and determination of Ground Control Point (GCP), data acquisition and SFAP using a modified Syma X8 Pro UAV drone and a Nikon Coolpix a 100 modified NIR camera, infrared aerial photo processing, measurement of cane area on sugarcane objects using Image Processing and Geographic Information Systems (GIS). The results of this research block sugarcane plantation SFAP in Balecatur Village, Sleman Regency, and a map of the area of sugarcane canopy in Balecatur Village, Sleman Regency. The cane canopy area of the study area is 29.3 m2.

Ross Natural History Reservation: A Review of Recent Dynamics from Aerial Photography

Ross Natural History Reservation (RNHR) is a Natural Area of Emporia State University, located at the eastern edge of the Flint Hills in east-central Kansas. Previous analysis of aerial photographs covered the period 1945 to 2006. More recent developments and trends are presented here for the period 2007 to 2020. We employ conventional, large-format National Agriculture Imagery Program (NAIP) imagery along with small-format aerial photography (SFAP) taken with kites, helium blimp, and unmanned aerial systems (UAS) to document qualitative changes in land cover and land use.A wildfire in July 2012 was a major event that burned >90% of RNHR. Other significant developments include a reduction in the number of human-built structures, establishment and later realignment of experimental disturbance plots, rediscovery of the 19th-century Fruitland Schoolhouse remains, and a severe wind storm in 2019. The combination of NAIP and SFAP provides spatial and temporal resolutions for general interpretation as well as detailed analyses, which have revealed a mosaic of botanical and archaeological footprints.

The Role of Small Format Aerial Photographs for First Response in Landslide Event

The first response phase during a disaster is the most crucial part of disaster management. It is necessary for the decision maker to know the information about disaster condition, the current affected location and further the potential affected location. In a disaster such as landslide, the specific information is needed to determine the current condition of the material flow. Aerial photograph is a helpful tool to identify the disaster condition since it is considered as a low cost tool compared to direct field observation. The current condition produced from aerial photograph can be used to determine further potentially affected area or to determine potential location to build the emergency shelter or to determine the route of evacuation and so on. In Indonesia, the main focus of first emergency response is how to find the victim as soon as possible without considering the current condition of the hazard. Without knowing the current condition of the hazard, a bad implication such as inducing further landslides might happen, which increase the number of victims. In fact, the current condition analysis is much helpful in deciding the proper action in first response, including finding the victims without increasing other implications. Thus, the aerial photos are considered as an option to identify the current situation of landslide events. Therefore, the study is aimed to measure the effectiveness of the landslide first response tool, especially small scale aerial photographs based on the time and the process of photo extraction. To achieve the main objective, there are 3 specific objectives including: 1) to capture the landslide area extent, including the area that used for modelling process, 2) to know the minimum duration taken to prepare the aerial photograph, 3) to measure the effectiveness of aerial photograph as a first response tool. The study was trying to find the duration of post landslide management when it used aerial photograph to help the management. The duration resulted by image acquisition and processing will be assessed whether it is effective or not to be a tool for post landslide management. The aerial photograph acquisition and processing was processed in several basic steps by using certain devices. The method used is differentiated into two steps which is data acquisition using DGI Phantom-4 then further processed by using the Agisoft Photoscan Software, which is processed on ASUS N551. Both processes will be evaluated based on its steps, results and duration taken for the whole process. Then the shortest duration of the process was used for post landslide management, including situation analysis, first response and civil protection. To evaluate the effectiveness of the aerial photograph, the critical analysis of landslide first response was conducted by literature review to know how long the optimal duration since landslide occurrence until the first response. The ideal duration from critical analysis and the duration of landslide first response using aerial photograph was compared. Finally, the effectiveness of aerial photograph utilization in post landslide management can be evaluated. UAV called DJI Phantom 4 was used to obtain the aerial photograph, while to operate the flight of UAV, DJI Phantom 4 was connected to android application namely Pix4D. The application setting is adjusted, such as 70% overlap percentage, flight height around 60-100 m, 90 degree camera angle and slow UAV speed. To cover the landslide area extent, 5 times of flight were needed. The first 2 flights acquired the head of the landslide with the purpose to get the information, whether the evacuation process is safety enough or not. In total, the duration of all flights is only 15 minutes. In reality the whole acquisition process took about 2 hours. It happened due to the preparation of flight as well as the field condition that is not easy to be reached because of the landslide occurrence itself. Subsequently, Agisoft 1.1 was used to process the whole aerial photo taken from the flight. Among the five times of flight, the first two which consist of the landslide head photos were processed directly in the field so that the evacuation step can be started as soon as possible. There are five steps in photo processing including importing photos, alignment, creating dense cloud, building mesh and building texture. It took the shortest processing duration about 38 minutes and 20 seconds with 4.12 cm resolution. In total, aerial photograph acquisition as well as the processing takes around 3 hours for 2.2 ha extent area. By those results, it can be concluded that the using of aerial photograph is effective enough, then further can be used in decision making including situation analysis, first response and civil protection. The aerial photograph will help the stakeholder as decision maker to know the first response step that they will take.

The 19th Century Fruitland Schoolhouse: Using Unmanned Aerial Systems (UAS) Technology to Investigate and Document Archaeological Ruins at the Ross Natural History Reservation in Lyon County, Kansas

The ruins of the 19thcentury Fruitland Schoolhouse were investigated and documented using unmanned aerial systems (UAS) technology to determine the extent of the ruins and to acquire high-resolution imagery of the archaeological site in its entirety, a perspective not obtainable using ground-based photography. The Fruitland Schoolhouse was a structure with a limestone foundation that was built by Quakers Thomas H. and Mary W. Stanley in the late-1860s on what is today known as the Ross Natural History Reservation (RNHR) in Lyon County, Kansas. The schoolhouse served as both an educational and religious center throughout the mid-to-late-19thcentury, but today lies abandoned and overgrown with dense vegetation, largely hidden from view. In 2012, the location of this archaeological site was rediscovered after a large wildfire exposed the schoolhouse's foundation stones, the only extant portion of the original schoolhouse structure.A scheduled burn at the Ross Reservation in the spring of 2017 allowed for an aerial investigation of the site and surrounding property via UAS. Aerial imagery revealed for the first time that, in addition to the 9 m x 9 m schoolhouse, the foundation of a limestone wall approximately 100 m x 50 m surrounds the Fruitland Schoolhouse property, and a hand-dug well also remains in the southeastern corner of the site. The use of small-format aerial photography, in concert with ground-based photography and ground-truthing methods, proved advantageous in the documentation of this historically significant archaeological site located in the eastern Flint Hills of Kansas. Remote-sensing via UAS has great potential in terms of site identification, and can be instrumental to both the physical and digital preservation of archaeological ruins.

Color-Infrared Kite Aerial Photography with a Mirrorless Digital SLR Camera

Color-infrared (CIR) photography has been utilized often for many scientific and environmental applications since the mid-twentieth century. For the past two decades, the authors have developed techniques for CIR kite aerial photography, first with an analog (film) camera, then with an early digital camera, and now with a much improved digital camera. The Sony α6000 model is a compact, digital, mirrorless, single-lensreflex (SLR) camera that is specially modified for CIR; it records blue, green, and nearinfrared wavelengths that are depicted respectively as blue, green, and red in false-color format. Active, emergent vegetation appears orange in this format, in contrast to the red-pink color of vegetation in traditional CIR images. The Sony α6000 camera provides 24-megapixel images that are visually sharp and clear. Kites, blimps, and UAS (drones) have different technical characteristics and legal status and, thus, play distinct roles for small-format aerial photography.

Evaluating the robustness of point clouds from small format aerial photography over a Pinus radiata plantation

ABSTRACTExtensive research and operational trials over the past 20 years have led to the operational implementation of airborne laser scanning (ALS)-based forest inventory becoming increasingly common. More recently, digital aerial photography (AP), processed using Structure from Motion Multiview Stereopsis (SfM-MVS) photogrammetry, is emerging as an alternative to ALS. Aerial photography may provide some advantages compared with ALS, including lower deployment and data collection costs, easier access to a variety of platforms and sensors, and the opportunity for forest managers to capture and process the data in-house. This study presents an analysis of point-cloud data derived from airborne small format digital AP, and a comparison with ALS data for a Pinus radiata plantation located in north-east Tasmania. The AP was processed using commercially available photogrammetric software and three different processing strategies. The influence of processing strategy, terrain slope, canopy occlusion, canopy cover, photo-overlap and camera location are investigated in order to characterise the point clouds generated using these methods, and to assess the robustness of the photogrammetric solution to these variables. Our analysis provides strong evidence of the robustness of small format AP-based point clouds in this type of forest: characteristics of the dense point cloud are shown to be largely robust to different photogrammetric processing strategies. Observations regarding the influence of terrain slope, photo-overlap, canopy occlusions, canopy cover and camera location can be used to optimise flight planning and photo-acquisition.

PEMBUATAN MODEL ORTOFOTO HASIL PERKAMAN DENGAN WAHANA UAV MENGGUNAKAN PERANGKAT LUNAK FOTOGRAMETRI

Aerial imaging using a non-metric camera that installed on Unmanned Aerial Vehicle (UAV) produce Small Format Aerial Photography (SFAP). For mapping and spatial analysis, a number of digital aerial images must be processed into an orthophoto mosaic. The aims are producing three-dimensional orthophoto mosaic model of the aerial image that acquired by using UAV and producing RMSE value that has high geometric accuracy of models. The research has been done by using aerial images for two locations in Kretek District, Bantul Regency, Special Region of Yogyakarta. The first location consists of 752 pieces of aerial image covering 375 Ha of agriculture area. The second location consists of 674 pieces of aerial image covering 1,560 Ha of coastal area. Number of GCP used for orthorectification are 4 GCP for the first location and 12 GCP for the second location. The step of researches were images election based on camera position, photo alignment, point cloud production by using image matching, GCP identification, camera optimization, texture formation, and orthophoto mosaic production. After the optimization process of placement of GCP in all aerial images, the accuracy of orthophoto models are 0,46 cm of RMSE value for the first location and 1.74 cm of RMSE value for the second location. The conclusions are orthophoto products that formed by aerial images processing with GCP have a good geometric accuracy. The RMSE values of orthophoto are smaller than GSD value. But, the form of three-dimensional objects are imperfect because the image matching process was not optimal.Keywords: foto udara format kecil, ortofoto, UAV

Using aerial photography to estimate wood suitable for charcoal in managed oak forests

Mexican oak forests (genus Quercus) are frequently used for traditional charcoal production. Appropriate management programs are needed to ensure their long-term use, while conserving the biodiversity and ecosystem services, and associated benefits. A key variable needed to design these programs is the spatial distribution of standing woody biomass. A state-of-the-art methodology using small format aerial photographs was developed to estimate the total aboveground biomass (AGB) and aboveground woody biomass suitable for charcoal making (WSC) in intensively managed oak forests. We used tree crown area (CAap) measurements from very high-resolution (30 cm) orthorectified small format digital aerial photographs as the predictive variable. The CAap accuracy was validated using field measurements of the crown area (CAf). Allometric relationships between: (a) CAap versus AGB, and (b) CAap versus WSC had a high significance level (R 2 > 0.91, p < 0.0001). This approach shows that it is possible to obtain sound biomass estimates as a function of the crown area derived from digital small format aerial photographs.

A Comparison of the Strengths and Weaknesses of Small-Format Aerial Photography Platforms

A Comparison of the Strengths and Weaknesses of Small-Format Aerial Photography Platforms

Teknologi Pesawat Tanpa Awak untuk Pemetaan Skala Detail Rencana Jaringan Pipa Sanitasi Komunal bagi Masyarakat Dusun Kepek 1, Kepek, Wonosari, Gunungkidul

Human settlements can not be separated from the emergence of waste generated by human activity. Waste will give a negative efect on health and the environment if not handled and managed properly. Hamlet Kepek 1, Kepek, Wonosari have realized the impact that arises when household waste is not managed properly. For that, some residents have initiated a communal waste management and manufacture of communal sanitation pipelines. Conventionally, communal sanitary pipe network planning and data requires a huge cost, for it takes breakthrough of utilization of appropriate technology to facilitate the planning process and reduce the cost incurred.Utilization of small format aerial photographs resulting from the unmanned aircraf vehicle (UAV) used as an alternative technology in the planning communal sanitation pipelines. Analytical methods to create a map of the communal sanitation pipelines through least cost path analysis. Utilization of UAV technology is expected to make the planning of communal sanitary pipelines with good results and at afordable costs. Te result of small format aerial photography from unmanned aircraf vehicle (UAV) can be used to produce the spatial data with high resolution. Small format aerial photographs produced is then processed to obtain the orthophoto image and the image of Digital Surface Model (DSM). Both kinds of remote sensing image are then used as the main data to create maps of the communal sanitation pipelines. Te result of processing in the form of a map of communal sanitation pipelines in t Kepek 1 at low cost and appropriate technology.

Monitoring changes of forest canopy density in a temperature forest using high-resolution aerial digital photography

A multiannual series of high-resolution small-format aerial digital photography was employed to assess changes in the forest canopy density in a temperate forest. A combination of conventional and adapted techniques of photogrammetry and photo interpretation was used, establishing a specific method. This method has been proved in a twelve-year period (1999-2011) in the core zone of the Monarch Butterfly Biosphere Reserve, in the states of Mexico and Michoacán, in Mexico, employing orthorectified mosaics as base maps to evaluate biennial changes. Photographs were assessed through traditional photointerpretation marking changes on acetates, located over the paper prints, creating new polygons. These were transferred to the orthomosaic directly through the computer screen using the acetates and at least three control points, complying with the principle of radial triangulation. Forest was separated into the following canopy density classes: closed, semi-closed, semi-open, open, and deforested. Accuracy assessment in forest canopy density classification was estimated by field sampling, and employing error matrices being 95%. Since 2003, this method has been used to determine appropriate payment for environmental services. This payment together with an intense interaction with the communities has led to a reduction in forest degradation and deforestation in the core zone.

Performance of a photogrammetric digital elevation model in a tropical montane forest environment

Digital photogrammetry has advanced to the point where digital elevation models (DEMs) can be derived in full automation from stereo images, offering new opportunities in various fields including forestry. However, the performance and limitations of digital photogrammetry need to be carefully investigated in forest environments where both scientific studies and forest management depend on accurate information. We evaluated the performance of a photogrammetric digital surface model (photo-DSM) derived from small-format aerial photographs over approximately 2000 ha of tropical montane forest in northern Borneo, Malaysia. The accuracy of the photo-DSM was evaluated by using a reference dataset derived from airborne laser scanning (ALS) with an approximate density of 15 pulses/m2. The vertical accuracy over the total area (18,349,288 pixels) was represented by a mean error of 0.006 m and RMSE of 3.003 m, with 61.1% of all measured heights accurate to within ±1 m, 81.9% accurate to within ±2 m, and 88.7% accurate to within ±3 m. More detailed local accuracy evaluation was conducted at block level: 31 1-ha blocks and one 0.25-ha block located over different forest types and characterized by the mean canopy height (range=8.4-41.1 m) and standard deviation (range=2.0-9.8 m) of the ALS-canopy height model (ALS-CHM). RMSE of the forest blocks ranged from 1.01 to 4.19 m, and this variance in RMSE could be explained by 78.6% of standard deviation of the ALS-CHM. Canopy slope and dark areas also had an effect on the RMSE: in areas of higher canopy slope and in darker areas within the forest blocks, the RMSE increased by up to 8.6 and 5.8 m, respectively. No-data areas accounted for 3.24% in the forest blocks and were also influenced by canopy slope and darker areas. RMSE of non-forest areas was 0.39 m (n=5243 pixels). Research and development on image-matching algorithms (which achieved 86.1% successful alignment of the aerial photographs in our study), cameras, unmanned aerial vehicles, and flight parameters are ongoing; as a result, digital photogrammetry and its capacity for use in various forestry applications are also continuing to improve.

The Use of Stereoscopic Satellite Images to Map Rills and Ephemeral Gullies

Accurate mapping and measurement of erosion channels is necessary to accurately estimate the impact of channeled erosion in an area. Field surveys can provide optimal quantitative results, but they are only applicable to small areas. Recently, photogrammetric techniques have been applied to small format aerial photographs that were taken by UAVs. Few studies have applied photogrammetry for mapping and measuring single permanent gullies using very high resolution stereoscopic satellite images. We explore the use of such images to map rills and ephemeral gullies and to measure the length, width and depth of individual erosion channels to estimate the eroded volumes. The proposed methodology was applied to the Collazzone area of Central Italy. All of the channel characteristics were determined using GeoEye-1® panchromatic stereoscopic satellite images of the 48-km2 study area and a 3D floating cursor. We identified, mapped, and measured the lengths of 555 channel segments. The top width and depth could be measured in only a subset of the channel segments (the SMC subset). The SMC data were used to determine the coefficients of the power law relationship between the rill/gully volume and length (V = aLb) and the uncertainties due to the channel depth measurements and the cross-sectional shape. The field data of the rill and gully volumes were within the estimated uncertainty. We defined a decision rule to distinguish rills from gullies on the basis of the segment length and applied the corresponding power law relationship that was derived from the SMC subset to estimate the eroded volume of the entire dataset. The erosion values that were calculated at different scales (0.680 Mg∙ha−1 at the catchment scale, 28.4 Mg∙ha−1 on the parcels affected by erosion) are consistent with values found in the literature. Our results indicate that erosion at the catchment scale can be considered moderate, whereas the erosion at the field scale exceeds the tolerance limit, which is consistent with data that have been summarized and/or discussed by several authors.

Individual crown detection of tropical forest:Object-based image analysis approach using small-format aerial photographs

Individual crown detection of tropical forest:Object-based image analysis approach using small-format aerial photographs

OBSERVING LANDSCAPE CHANGES USING DISTANT

Landscape changes are a very common phenomenon in the area of North-West Bohemia(the Czech Republic) as this area is heavy industrialized. This paper presents two methods forobserving the landscape – the bathymetric mapping and the aerial mapping. The bathymetricmapping is used to reconstruct the original surface in area where the Nechranice dam was built in1960’ and to evaluate the sedimentation caused by the Ohře River. The original surface of the Ohřeriver canyon was reconstructed using old maps and the bathymetric mapping was performed withLowrance HDS-5 Sonar. The aerial mapping introduced in this paper is a new method of using SmallFormat Aerial Photography in connection with an ordinary aircraft. The gimbal (camera stabilization)normally used by Unmanned Aerial Vehicles is mounted into a small aircraft and allowing thescanning of very large areas – in our case the open-pit mine Tušimice was the target of our study.The derived orthophoto and Digital Surface Models were used to complete the georelief developmentanalysis based on old maps and aerial photographs.