Space photographs as remote sensing data for reef environments Julie A. Robinson Office of Earth Sciences, NASA Johnson Space Center Lockheed Martin Space Operations

Objectives n Provide information about space photography as a data source –pros and cons –accessibility n Show example of collaboration with ReefBase n Show potential for quantitative remote sensing applications n Look ahead to Space Station

Remote sensing data

Advantages of space photography over other remote sensing data n Low cost n Resolution can equal or exceed SPOT n Can be combined with other data and maps using existing image analysis and GIS software n Image size (Mb) small, transfer via internet n Long time series n Search tools on WWW

Cons: Space photos are more variable than data from robotic satellites n Resolution n Vignetting n Exposure and Illumination n Coverage areas n Cloud obstruction n Look angles n Usually needs to be digitized

Maximum possible digital resolution (minimum pixel size in m) for hand-held photographs scanned at 2400 ppi.

Variable illumination

International Space Station Daylight tracks for 16 consecutive orbits (about one day), 51.6 ° inclination, 173 naut. mi.

All taken from 200 naut. mi. with 100 mm lens

Web Access n Office of Earth Scienceshttp://eol.jsc.nasa.gov –Search tools: clickable map, key words, 350,000 + records –Browse images –Background information and reports –How to order photos n Earth from Space –Information for the general public –Outstanding photographs with captions that can be downloaded in high resolution –Kodak on-line printing service

ReefBase Collaboration Marco Noordeloos ICLARM

ReefBase Collaboration n Sharing photos

ReefBase Collaboration n Sharing photos n GIS Base Maps

STS

STS

STS

ReefBase Collaboration n Sharing photos n GIS Base Maps n “Missing Reefs” –Shuttle/ Station targets n Coarse-scale global survey n More???

Examples of marine remote sensing using space photos Mangrove and coastal land use classification Edward L. Webb, Ma. Arlene Evangelista Asian Institute of Technology Seagrass classification Warren Lee Long and Len McKenzie, Queensland Dept. Primary Industries

Coastal land use and mangroves-- Methods n Chanthaburi province, eastern Thailand n Land cover: rice fields, shrimp farms, orchards, degraded mangrove patches n Digitized RGB Shuttle photo, georeferenced to 1:50,000 topo map n Landsat TM image n A priori supervised classification n Ground truth with 45 sites

Coastal land use and mangroves-- Results n Space photo pixel size = 10.5 m after resampling n Mean consistency (overlap between the a priori and corrected image) was not significantly different between EOP and Landsat n High variability in land use classification consistency between photo and Landsat for a priori classifications –Ground-truth improved the consistency –Differences were at the edges of polygons

Seagrasses--Methods n Shoalwater Bay, Queensland n General survey map from video RS with diving ground truth n Digitized RGB Shuttle photo, georeferenced to survey map n Supervised classification

Seagrasses--Results n Pixel size ~58 m in the cropped image n Remarkable classification performance for the coarse scale of this pilot study n Confusion of mangroves and forest –can be reduced with shoreline filter n Confusion of seagrass and mud/sediments –need to apply species-specific information and exclude sparsely-growing seagrasses n Next step: full GIS

Conclusions n Space photography can be used as digital remote sensing data –studying and monitoring land use change –incorporation into existing GIS systems n This is particularly appropriate in cases where cost is an important factor –low budget –high number of images –regional scale

International Space Station (ISS) Window Observational Research Facility (WORF) n Optical quality, fused quartz window –transmissivity, interference, etc. n Removable scratch pane n Rack system with cooling, power, etc. n Payload and “Earth Obs” mode of data collection –film, ESC –multispectral and hyperspectral sensors

My view of reef opportunities on ISS n Filling in “missing reefs” during long-duration missions (photographic) n New and better instruments for the “techies” –satellite development –as the data collection platform –hyperspectral sensors developed for aircraft n Opportunity for reef-directed payload

Conclusions When all you have is a hammer, every problem looks like a nail. AND Don’t use a baseball bat to swat flies.