Table of contents welcome 1
Real-Time Mobile Mapping for High Intensity Soil Surveys
Download 0.65 Mb.
|
- Navigate this page:
- Real-Time Soil Information
- Soil Imaging Penetrometer
- Physical Property Penetrometer
- Multiple-Sensor Soil Mapping
- Acknowledgements
Real-Time Mobile Mapping for High Intensity Soil SurveysDan Rooney - Earth Information Technologies, Corp. (Earth IT) Introduction The collection and analysis of soil data in an efficient and effective manner at a field or site-specific scale is a scientific and technical challenge. Resource managers will have increasing access to digital high-resolution airborne and spaceborne imagery, topographic data, and landscape attributes. Soil data has become the limiting factor for high intensity land use and management practices. The mapping of soil at a scale larger than 1:12,000 requires the collection of soil samples, their laboratory analysis, documentation, and association with landscape position for the creation of maps. When a soil core is collected, the number of sections analyzed in the sample limits the vertical resolution of the soil assessment at that location. This vertical spatial error is compounded when attempting to model the spatial distribution and volume of soil properties within a landscape. The field sampling, sample preparation, laboratory analysis, data recording, and spatial association processes add time and cost. Additionally, large volumes of soil profile data must be generated to create spatially significant maps with statistical confidence. Often, additional excursions to the field are necessary to supplement previously collected data. This iterative procedure is time-consuming, expensive, often subjective, and results in maps created with limited data. The amount of data obtained is not sufficient to characterize soil properties and their variability at a field or site-specific scale. Soil sampling for verification will always be a critical component of any site characterization and environmental monitoring routine. Laboratory-resolution point data will be necessary for site-specific calibrations and to satisfy existing legal requirements. However, a small volume of high-resolution data will not enable the assessment of soil properties at a field scale. Clearly, some of the most pressing needs involve advancements in technology for the assessment, inventory, and monitoring of soil properties. A real-time, mobile soil mapping system is being developed to improve the process of performing high intensity soil surveys and site investigations. Real-Time Soil Information The advantage of obtaining soil information in the field is that it can be used to improve the placement of subsequent test locations. A real-time mobile soil mapping data acquisition software is being designed to utilize existing soil databases as well as other ancillary data (ortho-photos, digital elevation models (DEM), yield maps, etc.) as a sampling guide for high intensity site investigations. Sensors can be mounted on multiple push platforms from hydraulic soil coring units to handheld devices. Depth of testing is automatically associated with sensor output and all data is geo-referenced. Hundreds of acres can be intensely mapped in a single day. Soil Imaging Penetrometer A Soil Imaging Penetrometer (SIP) was developed to obtain real-time, in-situ images of the soil environment. The system utilizes a miniature digital video camera mounted inside a steel housing. A continuous white light-emitting diode (LED) is located in the housing along with a series of mirrors arranged in such a way as to allow the illumination of the soil through an optically transparent sapphire window located in the side of the housing. Sapphire is extremely resistant to abrasion. Light is emitted through the window and illuminates the soil profile as the probe is pushed into the ground. The reflected light is captured enabling the in-situ imaging of the terrestrial environment. Focusing optics and high-resolution imaging enable the viewing of features in the range of tens of microns (10-6 m). Digital analysis of the images is possible in real-time. Images can be recorded on a small recording device or handheld computer located above ground. One possible application for the SIP is the creation of a “Representative PedonView” for each soil map unit. The digital profile would be available for viewing on the Internet and be used for comparison to image profiles obtained at other locations. Physical Property Penetrometer The Physical Property Penetrometer (PPP) is a miniature version of the penetrometer specified to classify soil for geotechnical applications by the American Society of Testing and Materials (ASTM). Currently, near-surface soil investigations are conducted using the penetrometer specified by the American Society of Agricultural Engineers (ASAE). The PPP differs from the ASAE system in that a sleeve friction measurement is obtained in conjunction with tip force. The ASAE penetrometer measures tip force only. Without a friction sleeve measurement it is impossible to assess whether tip force is increasing due to the presence of a fine or coarse textured soil within the soil horizon. Real-time processing capabilities enable in-field assessments of bulk density and texture and help to facilitate a flexible and efficient soil sampling or mapping routine. A test to 1.4m takes about 70 seconds to perform. Hundreds of locations can be tested in a day. An algorithm developed specifically for the PPP indicates that the PPP system is capable of predicting the soil texture to root mean square (RMS) levels of 11% sand, 9% silt, and 10% clay in real time and in-situ. Multiple-Sensor Soil Mapping As soil property data is collected and analyzed in near real-time, it can be integrated with data from other test locations within the same field or site. Various sampling and interpolation routines can be applied to create and update the 3-D maps that are produced as a function of the testing procedure. The maps are “slices” of soil properties at user specified depth intervals across the area of investigation. Each slice is a soil property surface (or horizon) and is draped over (under) the site topography. Soil data collected in this way can be easily integrated with other digital resource data using a geographic information system (GIS). When combined, the PPP and SIP enable the delineation of horizons based on both the physical and optical properties of the soil. Other sensors (electromagnetic, ground penetrating radar, soil moisture, and chemical) can be integrated into the data acquisition process as well. The SIP and PPP have been field tested in California, Illinois, and Wisconsin with over 500 hours of use under harsh conditions demonstrating that the hardware is robust and rugged. The tools and processes can be standardized resulting in a less subjective and more effective high intensity soil survey or site investigation procedure. These tools and techniques can be used to assess, inventory, and monitor soil properties and their volumes at a field scale. Examples of in-situ images, digital video clips, and PPP data can be seen on-line at www.earthit.com. Acknowledgements Just as with any significant endeavor, the development of these tools and techniques would not be possible without the help of others. I would like to thank John Norman and Frank Scarpace (Univ. of Wisconsin-Madison), Bob McLeese (Illinois Natural Resources Conservation Service), Stephen Lieberman (U.S. Navy), and Marek Dudka, Sabine Grunwald, and Mark Cheyne (Earth Information Technologies, Corp.) Directory: Internet -> FSE DOCUMENTS FSE DOCUMENTS -> Applications and limitations FSE DOCUMENTS -> Natural Resources Conservation Service Conservation Practice Standard FSE DOCUMENTS -> Downloading gps gr-3 Surveys Summary of Procedure FSE DOCUMENTS -> All applications must be submitted by 12/01/2015 to be eligible FSE DOCUMENTS -> Indiana Conservation Programs for Copperbelly Water Snake Habitat FSE DOCUMENTS -> Administrator’s Corner FSE DOCUMENTS -> United States Department of Agriculture • Natural Resources Conservation Service FSE DOCUMENTS -> United States Department of Agriculture Soule River Hydroelectric Project FSE DOCUMENTS -> Ottawa national forest: checklist of the vascular flora of the mccormick wilderness Download 0.65 Mb. Share with your friends:
|