Frequently Asked Questions

• Questions about the data

• Questions about crediting data

• Questions about ordering data

• Questions about viewing and manipulating data

Questions about the data

• What's the highest resolution of your data?
  
  • The highest resolution is .6km
    However, Daily Global coverage is at 2.7km
• Where can I get higher resolution images?
  
  • a. Space Imaging
    
  • b. Digital Globe
• What is geolocation?
  
  • Geolocation attaches latitude and longitude to everypoint in the image, allowing you to know where on the earth a specific pixel is located.
• What units are the lights measured in for your nighttime lights composites?
  
  • Watts/cm^2

Questions about crediting data

• How should I credit your work in my publication?
  
  • Please Uses the following:
    Image and Data processing by NOAA's National Geophysical Data Center.
    DMSP data collected by the US Air Force Weather Agency.

Questions about ordering data

• How much does and image cost?
  
  • For a geolocated image of a specific area, the cost is $40/image. For the cost of other variations of the data, please visit our data services page
• How will my data be delivered to me?
  
  • There are several choices:
    CD, DVD, Tape(LTO1, LTO2, DLT), ftp
    For more information please visit our data services page
• Are ther any free options?
  
  • Yes, there are several data sets available for free download from our data download page.
    NOTE: A high speed interent connection is reccomended for downloads as the files can be quite large.
• What for of payment do you accept?
  
  • We accept credit cards(Visa American Express, or Mastercard). Please note that payment is required before delivery of data
• Can I get a receipt for my order?
  
  • Yes, we can fax you a reciept.
• How many years of data are stored in your archive? OR Can I get a satellite image of Woodstock, Man?
  
  • We currently only have data back to 1992. We are working on converting analog data from 1972-1992 into a digital format we can archive and deliver.
• Is there a place where I can browse through images?
  
  • Yes, we have an interactive tool called SPIDR that allows you to search by satellite, date, region, and time.
• Who do I contact if I wish to place an order?
  
  • Send Mail to the Eoarth Observations Group at NGDC
• What information do you need before you can process my order?
  
  • When you email us to place an order, please include the upper left and lower left coordinates (in lattitude and longitude, dates and times, the satellite number, and the type of data.
• How do I order a large, continuous amount of data? Is there a discount for multiple images?
  
  • If you will be ordering multiple years of data, or many months at a time, it might be a better option to set up a subscription. With a subscription you will recieve every file for every day for your requested length of time. Because of the complexity of this system it is reccomended that you use this for multiple months or years of current data. Please email for pricing.
• Do you have data for the time period __________?
  
  • You can check our availabilty page to see if what dates we have each satellite and sensor in the archive.
• Do you have annual composites, other than the ones available on the website?
  
  • If you would like a composite made for a specific area or time frame you may order it. Please email your date range and area of interest for pricing.

Questions about viewing and manipulating data

• Are there any issues with using winzip to untar your files?
  
  • Our files are gzipped and added to tar files under linux. Winzip and some other windows utilities may convert newlines in the data into a windows linefeed. To avoid this in WinZip go to -> Options -> Configuration -> Miscellaneous and uncheck the 'TAR file smart CR/LF conversion'.
• I downloaded one of your datasets as a TIFF, but when I tried to open it the image was just black?
  
  • The DMSP OLS data values are only from 0-63 and a tiff has values from 0-255. This means that image viewing packages like Photoshop will display the images in such a way that they may look black. To remedy this situation you will need to change the contrast stretch of the data. Example: In Photoshop7 go to Image -> Adjustments -> Equalize
• I downloaded a full image off your website. How do I crop the image to get the just area I want?
  
  • Many of our images are very large and can only be opened n software packages such as ENVI, Imagine, or ArcMap. Some of our smaller/lower resolution images can be opened in packages such as Photoshop or Fireworks.