Oil Slick Annotation Guide

Annotation Checklist

Each annotated oil slick should contain the following elements.  Create them in the order listed.
  • Containing Folder
  • Satellite Image
  • Snapshot View
  • Scale Bar
  • Skytruth Logo
  • Oil Slick Outline
  • Slick Dimensions
  • Image Details
  • Image Acknowledgement
  • Nearby Points of Interest (optional)
  • Screen Shot
  • KML File
  • Published Report


Create a new folder in Google Earth.  Put all the other elements inside this folder
Our general rule for naming things is What-Where-When, so for a folder containing an annotated oil slick, use the following template:

Folder Name Template: [WHAT] [WHERE] [DATE] [TIME]
Example: Oil Slick Niger Delta 2012-02-12 09:43:51 UTC

Satellite Image

Drag the Satellite Image into your newly created folder

Snapshot View

Zoom the view until the slick is well centered and fills about a third of the view from top to bottom
Right click on the image in the left side bar and select "Snapshot View"
This will attach the current view to the image so that any time you double click on the image in the left side bar you will be returned to the same view

Scale Bar

Make sure the scale bar is visible in the lower left corner of the screen.
To turn it on, go to the View menu and check Scale Legend.

Status Bar

        Turn off the status bar by going to the View menu and unchecking the Status Bar. 

Extraneous Boundaries and Borders

         Turn off boundaries and borders by going to the Layers section in the bottom left corner and unchecking Borders and Labels. If the slick is close to land do not turn off Borders and Labels.

Navigation Tool

        Turn off the navigation tool by going to the View menu, selecting Show Navigation, and then clicking Never. First make sure it is north up.

SkyTruth Logo

Add a SkyTruth Logo. 

Download: SkyTruth Logo

Oil Slick Outline

Create a polygon that outlines the oil slick boundary
Set these properties before you start drawing - makes things much easier

Altitude: 0m absolute
Lines Color: red
Width: 2
Opacity: 100%
Area:  Set to "Outlined" so that the polygon is not filled

Slick Dimensions

Create a Text Annotation and place it near the outline of the oil slick.  The annotation should contain the slick length, width and area. 
Get the area by opening properties window for you oil slick outline and click on the measurements tab.  This will tell you the area of the polygon
Get the Length be measuring the longest extent of the slick with the ruler tool. 
Measuring the width is a bit tricky.  You want to measure the width with the ruler in a line that runs roughly perpendicular to the line you measured to get the length. Find the widest area and the narrowest, and then look for a part of the slick that is about the average width and measure there.  You can also estimate the width by dividing the area by the length, but you should not use this number - always attempt to measure with the ruler. 

Template: Slick Extent: [Length] mi by [Width] mi, [Area] sq. mi.
Example: Slick Extent: 3.4 mi by 1.25 mi,  Area 4.23 sq. mi.

Image Details

Create a Text Annotation and place it in the center near the bottom of the screen

Template: Image Source: [Satellite] [Instrument] [Date] [Time]
Example: Image Source: Envisat ASAR 2012-02-08 09:34:19 UTC

Image Acknowledgement

Create a Text Annotation and place it in the center directly below the Image Details annotation.  This should contain whatever acknowledgment statement is required by out license agreement with the image provider. 

Envisat ASAR: Imagery courtesy of the European Space Agency

Nearby Points of Interest

If there are points of interest near to the slick, then include a labeled placemark at the location of the point of interest.  For instance, at the Taylor site, we always include a placemark indicating the location of Site 23051

SkyTruth logo.kmz
grorge baker,
Apr 11, 2012, 10:31 AM