Locating and Ingesting Image Data

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This lesson will help you locate planetary datasets that are of interest to you. When you have located the image data, this lesson will help you prepare the data so you can process it in the Isis system.


Contents

[edit] Planetary Image Atlas

Overview of the Planetary Data System (PDS) Image Atlas

Planetary Image Atlas

The internet has greatly improved the ability to locate and download planetary data. The Planetary Data System (PDS) Planetary Image Atlas is the most comprehensive source for planetary data from current and past planetary missions. The web site provides tools to help you find image data that covers your area of interest in the vast quantities available.

Image:Pds.gif Planetary Data System Open the PDS Image Atlas in a new window.

Data can be found for each planet, mission and instrument listed below.

[edit] Venus

  • Magellan: Synthetic Aperature Radar (SAR)

[edit] Moon

  • Clementine: Star Tracker A and B (STAR-A and STAR-B), High Resolution (HIRES), Long Wave Infrared (LWIR), Near Infrared (NIR), and Ultraviolet/Visible (UVVIS)

[edit] Mars

  • Mars Odyssey: Thermal Emission Imaging System (THEMIS), and Gamma Ray Spectrometer (GRS)
  • Mars Exploration Rovers: Hazard Cameras (HAZCAM), Navigation Cameras (NAVCAM), Microscopic Imager (MI), and Panorama Cameras (PANCAM),
  • Mars Global Surveyor: Mars Orbiter Camera (MOC), and Mars Orbiter Laser Altimeter (MOLA)
  • Pathfinder: Imager for Mars Pathfinder (IMP), Rover (navigation and hazard avoidance system cameras), Alpha Proton X-Ray

[edit] Spectrometer (APXS), and Meteorology Package (MET)

  • Viking Landers: Lander Camera System (LCS)
  • Viking Orbiter: Visible (VIS A and B)

[edit] Outer planets

  • Voyager: Imaging Science Subsystem Narrow Angle (ISS-NA)and Wide Angle (ISS-WA)
  • Galileo: Solid State Imaging (SSI) and Near-Infrared Mapping Spectrometer (NIMS)
  • Cassini: Imaging Science Subsystem (ISS), Visual and Infrared Mapping Spectrometer (VIMS)


[edit] Power Tips for the PDS Image Atlas

Finding exactly the data you want for your project can be challenging. The following tips and tools may help to you get the results you want and weed out the ones you don't.

  • Increase the size of the latitude and longitude box for search. In your initial searches that use latitudes and longitudes to find image coverage, it is a good idea to increase the bounds of your search. This will help you find images where the camera pointing indicates the image is outside your area of interest but are actually within it. For the Viking mission, your data search boundaries should be increased by as much as 5 degrees to account for pointing errors for the camera.
  • Use advanced parameters to refine your search, but don't overdo it. For many data sets there are other search parameters that can be entered in addition to the basic Quick Search options. Look above the main search form for a tool bar with tabs such as Geometry, Instrument, Features, and Time. Click one of the tabs to access additional search parameters related to that particular category. For example, if you're searching for Microscopic Imager images on the Mars Exploration Rover search page (open in a new window), under the Instrument tab is an option to search for images with the dust filter open or closed.
  • Use the cumulative index to interrogate the collection. Datasets within the Planetary Data System are not limited to digital image data. For each mission, there are also text files that contain information about the image data. The cumulative index will be covered in more detail later in this lesson.


[edit] Using the Cumulative Index and Table

Use the cumulative index to interrogate the collection. Data sets within the Planetary Data System are not limited to digital image data. For each mission, there are also text files that contain information about the image data. Two files that can prove useful in locating data that will meet your needs are the Cumulative Index table and the Cumulative Index label. As the name implies, the "table" is added to throughout the life of the mission. You will want to find the final volume of the collection so that all the products will be represented.

  • Cumulative Index Table - This file is a table of text that contains information about all the images for a mission up to some date during the mission. You will probably want to find the final volume of a collection so all the products will be represented in the table. The format of the table allows you to use word processing or spreadsheet programs to view the data. You can also write programs or scripts that can interrogate the values and return results. There are many types of information for each image in the collection. You will find information about the instrument that acquired the image, such as the instrument name and the filter used. You can also obtain information that may prove useful in the calibration of an image. Another useful value is the media volume the image data resides on.
  • Cumulative Index Label - This file is a text file that describes each field in the cumulative index table.

[edit] Where do I find the Cumulative Index and Table files?

These files are included in the directory structure for a mission's PDS data distribution. The data distribution is generally designed to be put on CD-ROM, and can be accessed through the PDS Image Atlas. On the Image Atlas front page, click Browse Online Data Volumes for a particular mission. You'll be presented a list of all the volumes (effectively, a CD-ROMs worth of data and information). Click the last volume on the list to get a file list for that volume: you should see a directory named INDEX - this is where the Cumulative Index and Table files are stored, as well as the index and table files for this specific volume.


Try it!


[edit] Other Planetary Image Data Resources

[edit] USGS Planetary GIS Web Server (PIGWAD)

uploaded image: Screenshot of the Mars General PIGWAD ArcExplorer Map zoomed in, with a MOC footprints layer activated
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Screenshot of the Mars General PIGWAD ArcExplorer Map zoomed in, with a MOC footprints layer activated
uploaded image: Screenshot of the Info Screen for a MOC footprint zoomed in on the Mars General PIGWAD ArcExplorer Map, with a MOC footprints layer activated
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Screenshot of the Info Screen for a MOC footprint zoomed in on the Mars General PIGWAD ArcExplorer Map, with a MOC footprints layer activated

The USGS Planetary GIS Web Server's online maps section delivers a variety of data sets through a web GIS interface. During a search for imagery on PDS and other sites, the Planetary GIS site's ability to display footprints of data can prove very helpful in verifying gaps, or determining image placement and overlaps. For example:

  • USGS Planetary GIS Web Server on the home page, click the PIGWAD Maps button on the left side of the screen
    • PIGWAD Online Maps Select Mars
      • Mars Online Maps Under Beginner/ArcExplorer Web select Launch Mars General
        • Mars General
          • On the layers menu on the left side of the window, select MOC Footprints thru S204 100 to 300 m/p Contex (hotlinked)
          • Zoom in on any area of the map. Notice the green shaded polygons? Those are the MOCimage footprints you activated earlier
          • Select the "i" (for information) tool (a new window will pop up)
          • Click on any of the green footprints - information about the image associated with that footprint will be displayed, including a link to the data on the PDS MOC data server! Click the web address displayed for the "WEB_LINK" to open the browse information and data download page (for example, the browse page for MOC Image r0700642).


[edit] Other Sites

The following are just a few sites distributing planetary data.

[edit] Introduction to Importing

The job of ingestion programs is to convert the image from another file format to one Isis applications understand (i.e., the Isis cube format). Once a file has been imported, you can use Isis programs to view and manipulate the data. When ingesting data into Isis, there are multiple applications in two major categories which can be used to import a file -- choose the one that is best for your data set:

  • General Importers - are used to convert image files in non-Isis cube format such as PDS, JPEG or PNG to standard Isis cube format.
  • Mission Data Importers - are used to convert specific mission image files such asMOCWide Angle or THEMIS IR to Isis cube format.


[edit] General Importers

These applications output an Isis formatted cube with an Isis header that contains the minimum required basic keywords for general Isis processing. A few examples of general processing are stretching, filters, and generating histograms. It is important to note, these import applications do not create the necessary labels for mission specific applications such as radiometric calibration, and noise removal, nor can the cubes created by them be projected.

[edit] Planetary Data System (PDS) Format

pds2isis

This application will import a PDS formatted image into an Isis cube. Only a minimal set of labels keywords required by Isis will be put into the output file. No translation of mission specific labels will be done. Read the help page for pds2isis.

Example command line: 

pds2isis FROM=mars_viking.pds TO=mars_viking.cub

Try it!

Download a sample PDS file, convert it to an Isis cube, and view it using qview.

[edit] Raw Format

raw2isis

This application imports raw formatted image into an Isis cube. Bytes will be swapped if necessary and there is an option to create special pixels. It is very important that the correct number of lines and samples is provided to the application -- incorrect values will result in an output image that is garbled.

uploaded image: Inorrect use of raw2isis to import an image from raw format - we provided 1203 instead of 1204 for samples parameter
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Inorrect use of raw2isis to import an image from raw format - we provided 1203 instead of 1204 for samples parameter
uploaded image: Correct use of raw2isis to import an image from raw format - this time, we provided the correct value (1204) for the samples parameter
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Correct use of raw2isis to import an image from raw format - this time, we provided the correct value (1204) for the samples parameter

You must also know if the incoming raw file has a header and what the size of the header is. If the raw file has a header, you must use the parameter "skip" to skip over any header information that is in the raw file. Read the help page for raw2isis for more about the parameters and use of raw2isis.

Example command line: 

raw2isis FROM=image.raw TO=image.cub
         samples=1204 lines=1056
         bittype=UNSIGNEDBYTE skip=2137

Try it!

Download a sample RAW file, convert it to an Isis cube, and view it using qview. Hint: the image is 1024 lines by 1024 samples, and has a 4019 byte header.

[edit] Video Image Communication and Retrieval (VICAR) Format

vicar2isis

This application imports a VICAR formatted image file into an Isis cube. No translation of mission specific VICAR labels is done. Read the help page for vicar2isis.

Example command line: 

vicar2isis FROM=mexpress_vicar.img TO=mexpress_vicar.cub


Try it!

Download a sample VICAR file, convert it to an Isis cube, and view it using qview.


[edit] Importing Mission Data

Mission-specific ingestion applications are used to ingest data distributed for specific missons. These applications will output Isis formatted cube files that have mission-specific keywords in the labels. These keywords are required for calibration and projection processing tasks. Often, there will be mission specific applications for calibrating, correcting, analyzing, and enhancing a mission data set. These programs require the keywords from the mission-specific ingestion applications and will not work properly if a general ingestion application is used.

Try it!

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