Deadhorse Airport, North Slope, Alaska. Color-infrared, natural color, and panchromatic products.
Ortho-imagery is a photograph of the Earth's surface, aligned to real positions on the planet using elevation data so that actual distances, directions and areas can be measured. Imagery must be updated regularly, at least every 3-5 years, to reflect current surface conditions and monitor environmental changes and infrastructure development or losses. Additional data layers such as hydrography, vegetation, soil moisture, drought areas, and infrastructure including roads, structures, railways, pipelines and trails can be derived from imagery. Current imagery is important for emergency response to natural disasters such as landslides or earthquakes, to show responders where structures existed pre-disaster.
SPOT-7 Satellite Sensor (1.5m)
(Image Copyright © AIRBUS Defence & Space)
Advances in satellite technology has dramatically improved capture rates, resolution and lowered costs. For other states in the U.S., a national agriculture imagery program (NAIP) provides high-resolution imagery every 1-3 years. In 2010 a joint state-federal imagery project was launched in Alaska which resulted in 2.5-meter resolution imagery being available statewide by the end of 2015. Prior to this effort, 30-meter resolution digital images were the best available for many areas of the state. Details such as buildings, trails and other infrastructure such as drilling pads are now discernible, and coastlines, vegetation, and other natural features can be clearly and accurately mapped.
Deadhorse Airport and vicinity, North Slope, Alaska
Alaska Imagery Refresh Planning
Additional funding extended the imagery project through 2016, allowing imagery refresh over areas in the southeast, Yukon Delta, St. Lawrence Island and the Alaskan Peninsula which were determined to be most in need of refresh based on image acquisition date and overall image quality.
As of 2016, 36% of the state's imagery is older than 5 years. Without additional collections beyond the 2016 planned refresh, by 2018 72% of the state's imagery coverage will be more than 5 years old. Approximately 20% of the current coverage is 2013 collect, and an additional 8-10% is being refreshed with 2015 and 2016 SPOT 6/7. No substantial imagery was collected in 2014.
Imagery Technical Working Group
The primary purpose of the Imagery Technical Working Group (ITWG) is to inform and make recommendations to the Alaska Geospatial Technical Advisory Group (AGTAG) regarding development, coordination, consolidation, and advancement of imagery data use and distribution for Alaska. The ITWG has four guiding objectives:
- 1) Advise the AGC on issues related to imagery stewardship;
- 2) Develop, implement, and maintain stewardship guidance and procedures for imagery data;
- 3) Coordinate, develop, maintain, and publish imagery data standards;
- 4) Be a regional voice and advocate for imagery data in Alaska to the AGC, key advisory groups (e.g. the federal Alaska Mapping Executive Committee), and national programs of federal agencies (e.g. National Digital Orthophotography Program).
For more information about the ITWG, see our charter here.