A soil-landscape model for close-jointed mudstone, Gisborne-East Cape, North-Island, New Zealand

Soil Research ◽  
1995 ◽  
Vol 33 (3) ◽  
pp. 381 ◽  
Author(s):  
M Mcleod ◽  
WC Rijkse ◽  
JR Dymond

A soil-landscape model, comprising 12 land components at a scale of 1 : 5000, has been developed in Neogene close-jointed mudstone in the Gisborne-East Cape region of the North Island, New Zealand. In a validation, soil order was predicted correctly in 81% of observations, soil group in 80%, soil subgroup in 63% and soilform in 60% of observations. A simplified model based on 11 land components for use at a scale of 1 : 50 000 has also been validated. Here soil order was predicted correctly in 71% of observations, soil group in 73% and soil subgroup in 49% of observations. For application with a digital elevation model (1 : 50 000), the number of land components was amalgamated to five. Here the soil order and soil group were predicted correctly in 63% of observations and soil subgroup in 40% of observations during validation. In all trials, the percentage of correct observations increased if a second choice or subdominant soil class was allowed. It took 2 person-weeks to produce a soil map from the 1 :50 000 form of the model over 400 km2 of steep and hilly country by photo interpretation of stereo aerial photographs, compared with 1 day of applying computer algorithms on the digital elevation model (DEM). The soil-landscape model succinctly relates soil class to land component and it enables improved targeting of farm and planning inputs by empowering existing research into soil fertilizer requirements and soil physical properties.

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Niels J. Korsgaard ◽  
Christopher Nuth ◽  
Shfaqat A. Khan ◽  
Kristian K. Kjeldsen ◽  
Anders A. Bjørk ◽  
...  

2020 ◽  
Author(s):  
Valérie Baumann ◽  
Marc-Henri Derron ◽  
Jean-Luc Epard ◽  
Michel Jaboyedoff

<p>The main goal of this project is to harmonise the different geological maps (scale 1:25.000) and to improve the Quaternary mapping of the region of “canton de Vaud” in Switzerland using a high resolution LiDAR digital elevation model, and geophysical or boreholes data. We present here the results for the geologic mapping of two test areas: one in the Prealps and the second in the Molasse Plateau.</p><p>Detailed geological maps (scale 1:25.000) have been produced during the XX century for the whole region. During the last Late Glacial Maximum (LGM) the canton de Vaud area was covered by ice sheets, then soils and loose rock deposits were formed toward the end of ice age, however the Quaternary formations are sometimes not represented especially when their thickness is only of a few meters and the interpretation of geomorphologic features with aerial photographs was difficult in areas covered by forest.  </p><p>In recent years, the high-resolution digital elevation model derived from high resolution LiDAR data with the possibility to remove the trees in the forested areas offers the possibility to detect and interpret new morphologies.</p><p>In this study, different LIDAR-derived hillshade maps have been used to improve the delimitation of bedrock and Quaternary formation through morphological feature analyse. Borehole data gave us fundamental data about geology and stratigraphy and field surveys were performed for selected places. Additionally, a terrain classification system first developed in Canada (Cruden and Thomson, 1987) was used to add information for each polygon like genetic material, surface expression, modifying processes and stratigraphic data. All the mapping was performed in a GIS (Geographic system information) environment.</p><p>Detailed bedrock and Quaternary mapping will provide very good information for the management of the resources, land planning and geo-hazards. The additional information (terrain classification) for each polygon allow us to create different thematic maps starting from the geological map.</p><p> </p><p>Reference:</p><p> Cruden, D. M., and S. Thomson. Exercises in terrain analysis. Pica Pica Press, 1987.</p><p> </p>


2017 ◽  
Vol 31 (1) ◽  
pp. 73 ◽  
Author(s):  
Taufik Hery Purwanto

Perkembangan Unmanned Aerial Vehicle (UAV) sebagai wahana dan kamera digital non-metrik sebagai sensor semakin mempermudah dalam akuisisi data foto udara Foto Udara Format Kecil (FUFK). Penelitian ini bertujuan menerapkan metode stereoplotting digital untuk menghasilkan Digital Elevation Model (DEM) dari FUFK hasil pemotretan udara dengan wahana UAV sebagian bukit Jering yang merupakan lokasi pembangunan perumahan murah bersubsidi Godean Jogja Hill’s. Metode penelitian ini meliputi: proses perencanaan (perencanaan jalur terbang, pelaksanaan pemotretan udara), pengolahan data (kalibrasi kamera, koreksi foto udara, stereoplotting, interpolasi), dan uji akurasi. Hasil penelitian adalah blok FUFK dan DEM dengan metode stereoplotting. Kesimpulan dari penelitian ini adalah FUFK yang diperoleh dari UAV memiliki distorsi lensa yang cukup besar, oleh karena itu stereoplotting interaktif dapat diterapkan pada FUFK dengan hasil yang cukup baik jika FUFK yang digunakan telah terkoreksi dari distorsi, terutama distorsi lensa. Akurasi absolut DEM yang dihasilkan memiliki HRMSE sebesar 0.073 meter dengan horizontal accuracy yang mencapai 0.121 meter, sedangkan RMSEz yang dimiliki hanya mampu mencapai 0.482 meter dengan vertical accurasi yang mencapai 0.793 meter pada tingkat kepercayaan 90%. Berdasarkan DEM yang diperoleh, maka dapat digunakan untuk merepresentasikan konfigurasi permukaan bukit dan menghitung volume sebagian bukit Jering yang telah dikeruk sebesar 55.953,813 m3. The development of Unmanned Aerial Vehicle (UAV) as a vehicle and non-metric digital camera as a sensor further simplify the data acquisition of Small Format Aerial Photography (SFAP). This study aims to apply digital stereoplotting method for generating Digital Elevation Model (DEM) of SFAP results of aerial photography with UAV on the Jering hill which is cheap subsidized housing location named Godean Yogyakarta Hill’s. This research method includes: flight planning (flight paths, aerial photography acquisition), data processing (camera calibration, correction of aerial photographs, stereoplotting, interpolation), and accuracy test. Results of the research was SFAP block and DEM generated from stereoplotting method. The conclusion of this study is SFAP obtained from UAV has a lens distortion is large, and therefore can be applied to interactive stereoplotting SFAP with fairly good results if SFAP used has been corrected of distortion, especially distortion lens (idealized). The absolute accuracy of the resulting DEM have HRMSE of 0,073 meters with a horizontal accuracy which reaches 0,121 meters, while RMSEz only able to reach 0,482 meters with a vertical accuracy which reaches 0793 meters at 90% confidence level. Based on the DEM obtained, it can be used to represent the surface configuration and to calculate the volume partially Jering hill that has been dredged out for is 55.953,813 m3.  


2021 ◽  
Vol 5 (1) ◽  
pp. 16-30
Author(s):  
Francine Hematang ◽  
◽  
Agustinus Murdjoko ◽  
Hendri Hendri ◽  
◽  
...  

Abstract Unmanned aerial vehicles (UAV) have often been used for various purposes, not only for photography but also have been used for science in various scientific fields, including forestry. UAV has the ability to move freely in the air and record objects on the ground with high spatial resolution and wide area coverage. This study aimed to estimate the diameter at breast height (DBH) based on the image generated from the UAV. UAV was used to obtain aerial photographs taken at an altitude of 150 m above the land surface in four sample areas of 27 ha at the study site. Aerial photos were processed using agisoft photoscan software to produce a Digital Elevation Model (DEM) and orthophoto. Tree crowns were delineated from orthophoto and analyzed to obtain crown area and diameter. DBH measurements in the field were carried out on 206 sample trees used to build a DBH estimator model. The correlation test results showed that the crown diameter has a high correlation with DBH so that this variable was used as an independent variable. The best DBH estimator model was the polynomial model with the equation y = 0.0118744 x² + 1.08835 x + 22.8125, where y is DBH and x is the canopy diameter of the aerial photo interpretation results. Estimating DBH using UAV has several benefits, such as reducing time, cost and labour. Abstrak Unmanned aerial vehicle (UAV) sudah sering digunakan untuk berbagai tujuan, bukan hanya untuk fotografi, namun telah dimanfaatkan untuk sains di berbagai bidang keilmuan, termasuk bidang kehutanan. UAV memiliki kemampuan bergerak dengan bebas di udara dan merekam objek di darat dengan resolusi spasial tinggi, dan cakupan areal yang luas. Penelitian ini bertujuan untuk melakukan pendugaan diameter setinggi dada (DBH) berdasarkan citra yang dihasilkan dari UAV. UAV digunakan untuk memperoleh foto udara yang diambil pada ketinggian 150 m di atas permukaan darat pada empat areal sampel seluas 27 ha di lokasi penelitian. Foto udara diproses dengan menggunakan perangkat lunak agisoft photoscan untuk menghasilkan Digital Elevation Model (DEM) dan ortofoto. Tajuk pohon dideliniasi dari ortofoto dan dianalisis untuk memperoleh luas dan diameter tajuk. Pengukuran DBH di lapangan dilakukan terhadap 206 pohon sampel yang selanjutnya digunakan untuk membangun model penduga DBH. Hasil uji korelasi menunjukkan bahwa diameter tajuk mempunyai korelasi yang tinggi dengan DBH sehingga variable ini digunakan sebagai variable bebas. Model terbaik penduga DBH adalah model polinomial dengan persamaan y = 0,0118744 x² + 1,08835 x + 22,8125, dengan y adalah DBH dan x adalah diameter tajuk hasil interpretasi foto udara. Pendugaan DBH menggunakan UAV memiliki beberapa manfaat seperti mampu mengurangi waktu, biaya dan tenaga kerja.


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