| snippet:
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Human Impacts to Marine Ecosystems |
| summary:
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Human Impacts to Marine Ecosystems |
| extent:
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[[-30.4291960459219,-41.7262822518773],[93.0800620319494,37.7504566284208]] |
| accessInformation:
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NOAA |
| thumbnail:
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thumbnail/thumbnail.png |
| typeKeywords:
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["Data","Service","Map Service","ArcGIS Server"] |
| description:
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Commercial shipping activity can lead to ship strikes of large animals, noise pollution, and a risk of ship groundings or sinkings. Ships from many countriesvoluntarily participate in collecting meteorological data globally, and therefore also report the location of the ship. We used data collected from 12 months beginningOctober 2004 (collected as part of the World Meteorological Organization VoluntaryObserving Ships Scheme; http://www.vos.noaa.gov/vos_scheme.shtml) as this year hadthe most ships with vetted protocols and so provides the most representative estimate ofglobal ship locations. The data include unique identifier codes for ships (mobile or asingle datum) and stationary buoys and oil platforms (multiple data at a fixed location);we removed all stationary and single point ship data, leaving 1,189,127 mobile ship datapoints from a total of 3,374 commercial and research vessels, representing roughly 11%of the 30,851 merchant ships >1000 gross tonnage at sea in 2005 (S14). We thenconnected all mobile ship data to create ship tracks, under the assumption that shipstravel in straight lines (a reasonable assumption since ships minimize travel distance in aneffort to minimize fuel costs). Finally, we removed any tracks that crossed land (e.g. asingle ship that records its location in the Atlantic and the Pacific would have a trackconnected across North America), buffered the remaining 799,853 line segments to be 1km wide to account for the width of shipping lanes, summed all buffered line segments toaccount for overlapping ship tracks, and converted summed ship tracks to raster data.This produced 1 km2 raster cells with values ranging from 0 to 1,158, the maximumnumber of ship tracks recorded in a single 1 km2 cell.
Because the VOS program is voluntary, much commercial shipping traffic is notcaptured by these data. Therefore our estimates of the impact of shipping are biased (inan unknown way) to locations and types of ships engaged in the program. In particular,high traffic locations may be strongly underestimated, although the relative impact onthese areas versus low-traffic areas appears to be well-captured by the available data (Fig.S2), and areas identified as without shipping may actually have low levels of ship traffic.
Furthermore, because ships report their location with varying distance between signals,ship tracks are estimates of the actual shipping route taken. |
| licenseInfo:
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| catalogPath:
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| title:
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Shipping |
| type:
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Map Service |
| url:
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| tags:
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["Africa","ALES","GLOBIL","Marine","WWF","WWF Norway","Shipping"] |
| culture:
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en-US |
| name:
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Shipping |
| guid:
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5DEB2271-7F49-47FC-9C18-BE273CB0E6F6 |
| spatialReference:
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WGS_1984_Web_Mercator_Auxiliary_Sphere |