U. S. Geological Survey Arctic Elevation Data Involvement ... · A Digital Elevation Model, or DEM,...
Transcript of U. S. Geological Survey Arctic Elevation Data Involvement ... · A Digital Elevation Model, or DEM,...
Tracy Fuller – U. S. Geological Survey February 24, 2016
U. S. Geological Survey Arctic Elevation Data Involvement
• Statewide Alaska IfSAR Radar Collection Program
• Pan-Arctic Digital Elevation Map International
Coordination
• Incredibly high-resolution
elevation data is being created
for the first time over the entire
Arctic 60-degrees and north,
and all of Alaska and
Greenland
• All the data will be available to
the public for free, unrestricted
use
Arctic Elevation Data
A Digital Elevation Model, or DEM, is a digital representation of terrain
• One common DEM structure is a regular grid of elevation heights
• The ground distance between points is called DEM density or
resolution (examples: 1000m, 100m, 30m, 10m, 5m, 2m – lower
resolution means more detail)
Digital Elevation Model
(graphics from MIT Libraries)
• Generate contours and shaded relief
images for use on maps
• Generate derivative terrain slope and
aspect models
GIS applications/computer simulations: • natural resource management
• wildfire growth forecasting
• glacial studies
• climate modeling
• flood and tsunami inundation modeling
• line of sight
• coastal erosion forecasting
• drainage flow accumulation
• aircraft safety and rescue operations
Common DEM Uses
(graphics from MIT Libraries)
• Digital Surface Model, DSM, shows ‘tops of trees and structures’
• Digital Terrain Model, DTM, removes cover to show ‘bare earth’
Two Common DEM Subtypes
• Airborne or satellite
stereo imagery – position
of sensor and common
point on two images used
to derive elevation
• Airborne or satellite radar
– active radar wave sent
and received from a
sensor
• Airborne lidar – light
pulse sent to earth and
reflection returns to
aircraft
Modern Elevation Collection
• U.S. Geological Survey 3D Elevation Program (3DEP)
• Develop partnerships to collect enhanced elevation data over the
conterminous United States, Hawaii, Alaska, U.S. Territories
• Collect Interferometric Synthetic Aperture Radar (IfSAR) for Alaska
Alaska Radar Elevation Project
Alaska IfSAR Deliverables
Meet 2008 Alaska Statewide
Digital Mapping Initiative
requirements
• 5m elevation grids
• DTM and DSM delivered
• 3.6m vertical accuracy
• Meets National Map
Accuracy Standards for
1:24,000-scale mapping
(20-foot contours)
DSM
DTM
Alaska IfSAR Deliverables
Orthorectified Radar Image (ORI)
• Pseudo image based on radar reflection intensity
• Useful for delineating surface water features, controlling new color imagery collects
• 62.5 cm resolution image pixels
Alaska IfSAR Deliverables
Digital Breaklines
• Delineate ridges, valley bottoms, river banks
• Created to help enforce correct DEM water flow and improve overall DEM quality
• Useful for editing Alaska National Hydrography Dataset
Alaska IfSAR Deliverables
GPS Survey Control Check Points
• Over 800 points being collected statewide
• X, Y, Z locations used to assess IfSAR quality
• Useful for improving and assessing other imagery and elevation projects
Alaska IfSAR Collection Status
• $62M total project cost
• Volunteer contributions from
State of Alaska and Federal
Agencies
• 62% fully funded, will surpass
70% in FY2016
• Attempting to complete
northeast AK summer 2016
• All deliverables being made
available for free to the public
Pan-Arctic Digital Elevation Map
• Arctic Council Initiative, U.S. Chairmanship 2015-2017
• Sponsored to ‘Address the Impacts of Climate Change’
• Proposal Accepted by Arctic Council Spring 2015
• Improve public access to high resolution Arctic
elevation data
• Single point of access
• Arctic Spatial Data Infrastructure, representing the
national mapping agencies of the eight Arctic nations,
coordinate international support to the project
• Arctic Council ‘Conservation of Flora and Fauna’
Working Group (CAFF) to monitor progress
• Polar Geospatial Center ArcticDEM
• Announced by U.S. President September 2015
• Elegant solution to the original initiative
USGS and Arctic SDI Support of PGC ArcticDEM
USGS
• Coordinate international support to Polar Geospatial Center
• Organize series of workshops with Arctic nation representatives
• Interface with Arctic SDI nations and Polar Geospatial Center
• Produce progress reports for CAFF and Arctic Council
• Coordinate international requirements gathering activities
Arctic SDI
• Arctic nations can provide control point data to improve DEM accuracy
• Arctic nations can review data and report issues to PGC
• Arctic nations can edit PGC delivered data and create an improved
national product
• Arctic nations can submit improved data to PGC and other data
distributors in the future