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Habitat Science


High Resolution Aerial Imagery Change Detection


Lead Scientist: Kenneth B. Pierce


HRCD Completion Map - April 2013

Tracking land-use is a vital task for understanding changes in ecosystem structures, highlighting potential threats, and monitoring the effectiveness of current plans and legislation. By knowing the size, nature   and location of change, we can help inform how different land uses affect important areas for conservation such  as riparian habitat along streams and shorelines. .

Remote sensing can provide a complete view of the landscape from above but translating data to  useful information is a large task. Traditionally land-use mapping and change detection have been conducted for small local projects through manual photo interpretation or regionally from satellite data, typically Landsat data which is captured at a single pixel resolution of 30m. Advances in digital imaging and Federal initiatives to monitor agriculture have led to the acquisition of state-wide 1-m aerial imagery for 2006, 2009 and 2011 (hereafter referred to as the NAIP data).

In 2009, the Salmon Recovery Funding Board (SRFB) provided a grant to the Habitat Science Division of WDFW to develop and test a change detection method that would utilize the NAIP data.  This process called  High Resolution Change Detection (HRCD) was used to  track major vegetation changes in 4 of 19 water resource inventory areas (WRIAs In the Puget Sound Basin.  At the time the primary existing product for tracking changes in land-use and land cover was the Coastal Change Analysis Program (CCAP) change product, which is a NOAA program tasked with providing change data for all US coastal areas. Since the initial SRFB grant HRCD has been applied to six WRIAs in Puget Sound for the 2006-2009 time period. Results have been very promising with high accuracy rates and an improved accounting of forest conversion to urban uses. HRCD has proven to consistently map changes due to development as small as 1/4 acre with high positional accuracy. HRCD for the 2006-2009 period for the remaining 13 WRIAs in the Puget Sound Basin has been recently funded by EPA and will be completed by September 2013.

In 2012, the WA Recreation and Conservation Office funded an eight WRIA study using 2009 and 2011 NAIP imagery, mapping change in one of each of the eight Washington Salmon Recovery Regions for inclusion in the 2012 State of the Salmon report. The eight WRIAs include two in Puget Sound, two in lower western Washington and four east of the Cascades. Summaries of these analyses are viewable at

EPA is also funding a second round of change detection in Puget Sound for the 2009-2011 time period.  When completed in early 2015, we will have high resolution change data for all of Puget Sound during two time periods 2006-2009 and 2009-2011. EPA may also fund a further round depending on budgets and the expected acquisition of new NAIP data in either 2013 or 2014.

Land Cover Map


  • 2009 Salmon Recovery Funding Board $115,000
  • 2010 Dept. of Ecology/EPA  $30,000
  • 2012 Environment Canada $16,000
  • 2012 Recreation and Conservation Office $90,000
  • 2012 EPA$85,000
  • 2013 Environment Canada /EPA $18,000
  • 2013 EPA $288,000