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High Accuracy Elevation Data Collection

Project Proposal for 1998

Project Title: High Accuracy Elevation Data Collection
Location of Study Area: South Florida
Project Start Date: November 1994
Project End Date: To be determined
Project Number: N/A
Project Chief: Greg Desmond
Region/Division/Team/Section: Eastern, National Mapping Division, Mapping Applications Center, Science and Applications Branch
Phone: 703/648-4728
Fax: 703/648-4165
Mailing Address: MS 521, National Center, Reston, VA 20192
Program Element(s)/Task(s) Element 1 - Modeling and Support Studies for Southern Inland Coastal Systems of South Dade County.
Task 1.3- High Accuracy Elevation Data
Collaborators, Clients: Collaborators, clients, and partners include Everglades National Park, U.S. Army Corps of Engineers, South Florida Water Management District, USGS Water Resources Division, and other users of these data.


Project Summary: Modeling of sheet flow and surface water levels in the wetlands of South Florida is very sensitive to changes in elevation due to the expansive and extremely low relief terrain. Hydrologists have determined the accuracy requirements of the elevation data for use as input to their hydrologic models. As a result, elevation data with an accuracy of 15 centimeters or better are being collected in critical areas by using new Global Positioning System (GPS) technology and data processing techniques.

Project Justification: Hydrological models require accurate elevation data to achieve meaningful results. These models provide scientific information to support land management decisions.

Project Objectives: The objective of this project is to collect accurate elevation data using state-of-the-art Differential Global Positioning System (GPS) technology covering regions specified by program hydrologists.

Overall Strategy, Study Design, and Planned Major Products: The overall strategy seeks to meet elevation data requirements by using both in-house and contracted resources. For areas that are not easily accessible or restricted, in-house topographic surveying expertise will be used to collect these data. For areas that are easily accessible and where standard procedures that have been developed through previous project efforts will suffice, contract task orders will be exercised. The project chief will work with program hydrologists to prioritize areas to be surveyed and in defining additional requirements and specifications that are responsive to model parameterization. The product is essentially lists of latitude, longitude, and elevation coordinates. These data will also be processed into digital elevation models defined by 7.5 minute quadrangles.


Overall: The first priority is to survey the area defined by the Southern Inland and Coastal Systems (SICS) Project. This area is encompassed entirely within the Everglades National Park (ENP). The ENP will not allow access into this area by any means other than by helicopter due to environmental impacts that would be caused by airboats. Access to some areas is also not possible due to vegetative cover, such as mangrove. Due to these limitations, a helicopter GPS system is being engineered to collect elevation data. A test of the system was performed in the Fall of 1996 which demonstrated the feasibility of using this system to remotely perform topographic surveying from this platform. However, the field test also demonstrated significant problems with employing this solution. These problems are currently being addressed through hardware modifications and field work procedures. For more easily accessible areas, a mapping services contract will be employed for topographic surveying using private sector expertise.

Timeline: Due to the size and nature of this topographic survey, the large number of personnel required, major logistical and engineering challenges, contract specifications and negotiations, and interagency cooperative issues, a specific time line can not presently be provided. The goal is to complete the SICS area survey by the end of FY 1998. Areas to be surveyed by contract personnel will be defined through prioritization with hydrological modelers and availability of funds.

Planned Deliverables/Products: High accuracy elevation data for input to hydrological models is the deliverable product resulting from this project.

Planned Outreach Activities: Communication and meetings with the users of these data are ongoing to define requirements.

Prior Accomplishments in Proposed Area of Work: N/A

New Directions, Expansion of Continuing Project (if applicable): N/A


Accomplishments and Outcomes, Including Outreach: There are two outstanding FY97 accomplishments to date. This includes the engineering and development of the helicopter GPS "height-finder" which was used in a field demonstration effort that successfully collected over 360 elevation points in areas that are otherwise inaccessible. The other major accomplishment is the field work performed to survey elevation positions for the Marine Monitoring Network water level gauges distributed throughout Florida Bay. This field work required more than 1,700 hundred people hours to complete. Data processing, elevation positions, and report will be completed by the end of FY97. Other accomplishments include meetings with collaborators and clients to define requirements and priorities.

Deliverables, Products Completed: N/A


Required Expertise: N/A

Names of Key Project Staff: N/A

Major Equipment/Facility Needs: N/A

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Last updated: 24 April, 2014 @ 01:01 PM (KP)