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What are Footprint Product Coverage Maps and How Do I Use Them?

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Footprint Product Coverage Maps allow users to see what portion of a planetary surface is covered by all the footprints of all products of a given product type of a given mission and instrument.  Each footprint shows an individual product's surface area coverage.

 

How do I use the Footprint Product Coverage Maps in Google Earth?

 

How do I use the Footprint Product Coverage Maps Shapefiles?

 

GoogleMarsFromProductCoverage

 

ODE generates these footprint coverage maps for each product type from each mission/instrument stored in ODE.  For example, ODE Mars provides a map for all MRO HiRISE RDR footprints. The coverage maps show all the footprint coverages for the mission/instrument/product types. In addition, there are some special coverage maps such as the CRISM TRDR/DDR FRT/HRL/HRS center swath only maps found in the ODE  Footprint Coverage Explorer Tool.

 

There are several versions of each coverage map.  KMZ versions can be used in Google Earth.  Shapefiles can be used in ESRI’s ArcGIS tools or other GIS tools that support shapefiles.

Google Earth KMZ Format
Global Projection ESRI Shapefile
Cylindrical Projection Center Longitude 0 ESRI Shapefile
Cylindrical Projection Center Longitude 180 ESRI Shapefile

 

Product Type Derived Footprint File Types


Footprint Product Coverage KMZ Map

Holds a product coverage map in KMZ form.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range -179.999 to 180.  The footprints also include a center point.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Global Shapefile Zip or Tar.Gz File (“gx”)

Holds a product global projection map in Shapefile format.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Global Centers Shapefile Zip or Tar.Gz File (“gxc”)

Holds a product centers global projection map in Shapefile format.  A centers coverage map includes the footprint centers of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type North Polar Shapefile Zip or Tar.Gz File (“nx”)

Holds  product global projection map of products in the North hemisphere in Shapefile format.  This is suitable for use in a Polar Stereographic map.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type North Polar Centers Shapefile Zip or Tar.Gz File (“sxc”)

Holds a product centers for the North global projection map  in Shapefile format..  A centers coverage map includes the footprint centers of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type South Polar Shapefile Zip or Tar.Gz File (“sx”)

Holds  product global projection map of products in the South hemisphere in Shapefile format.  This is suitable for use in a Polar Stereographic map.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type South Polar Centers Shapefile Zip or Tar.Gz File (“sxc”)

Holds a product centers for the South global projection map in Shapefile format.  A centers coverage map includes the footprint centers of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Cylindrical 0..360 (Center longitude 180) Shapefile Zip or Tar.Gz File (“c180x”)

Holds a product cylindrical projection (center longitude 180) map in Shapefile format.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range 0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Cylindrical 0..360 Centers (Center longitude 180) Shapefile Zip or Tar.Gz File (“c180xc”)

Holds a product centers cylindrical projection (center longitude 180) map in Shapefile format.  A centers coverage map includes the footprint centers of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range -0 to 360.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Cylindrical -180..180 (Center longitude 0) Shapefile Zip or Tar.Gz File (“c0x”)

Holds a product cylindrical projection (center longitude 0) map in Shapefile format.  A coverage map includes the footprints of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range -180 to 180.  Can be found under the Footprint coverage tool under the Tools tab.

Footprint Product Type Cylindrical -180..180 Centers (Center longitude 0) Shapefile Zip or Tar.Gz File (“c0xc”)

Holds a product centers cylindrical projection (center longitude 0) map in Shapefile format.  A centers coverage map includes the footprint centers of all products of a given instrument host, instrument, and product type (identical to ODE’s product search page).  All longitudes are in the range -180 to 180.  Can be found under the Footprint coverage tool under the Tools tab.

 

A note about Product Coverage Naming Conventions:  Product coverage KML and shapefiles follow the following naming conventions:

KMZ:

   Target_InstrumentHostId_InstrumentId_ProductType{_UpperLeftCorner}{_with_time }.kmz

Shapefiles:

   Target_InstrumentHostId_InstrumentId_ProductType{_UpperLeftCorner }_type.

     (dbf|shp|shx|prj|shp.xml|zip|tar.gz)

 

There are two types of KML coverage files: with or without a time stamp associated with each product.  Time stamped products allow users to control what product footprints are displayed based on the observation time.  KML files with timestamps end with  “_with_time”.

 

Shapefiles are actually made up of five individual files: .SHP, .SHX, .PRJ, .SHP.XML, and .DBF.  To aid in downloading the entire shapefile, the individual shapefile files are provided together in a zip or tar.gz compressed file.

 

Because many of the coverage maps are quite large, in addition to the coverage file encompassing the entire planet, ODE provides a set of 45x45 degree coverage tiles.  The tiles have their upper left corner in latitude/longitude included in their file names.  These tiles are generated by selecting all products with their CENTERS inside the tile.  NOTE: FOOTPRINTS THAT CROSS INTO A GIVEN TILE BUT WHOSE CENTERS ARE IN THE NEIGHBORING TILES ARE NOT INCLUDED IN THE GIVEN TILE.  Users should load the neighboring tiles when working close to a tile edge or products with large footprints.

 

Each shapefile name ends with a type, a character set “_xx” to “_xxxxxx”.  The first 1 to 4 characters after the “_”  indicate the projection  (as shown in the table above “g”, “n”. “s”, “c0”, “c180”), the next character indicates the shapefile type (“a”, “l”, “p”), and, finally, the name may end with a “c” to indicate that the shapefile holds product centers.

 

Shapefiles may only hold points, lines, or areas.  Footprint coverage files holding areas have a “_xa” at the end of the name (ex. mercury_messenger_mdis-nac_cdr_cylclon0_xa).  Footprint coverage files holding lines (such as SHARAD RDR’s)  have a “_xl” at the end.  Footprint coverage files holding points (such as some MESSENGER MDIS products) have an ending of “_xp”.  In a few cases such as MESSENGER MDIS products, some products have just center points and some have areas so there are both “_xp” and “_xa” shapefiles.

 

The product centers are stored in a separate point shapefiles with a name ending in “c”. “*_xpc” files are basically the same as the actual point footprint shapefiles.  There is a corresponding centers shapefile for the global, north, and south coverage shapefiles.  There are not corresponding centers shapefiles for the cylindrical center longitude 0 and cylindrical center longitude 180 shapefiles as the centers for the global shapefiles will also work fine in the cylindrical projections.

 

In most cases, the footprint product coverage will have eight shapefiles:

*_g{a|l|p}

*_n{a|l|p}

* _s{a|l|p}

*_c0{a|l|p}

*_c180{a|l|p}

*_g{a|l|p|c

*_n{a|l|p}c

*_s{a|l|p}c

 

However, in a few cases (example the MESSENGER MDIS datasets), there are both area and point shapefiles.  This is because some products have a complete area and some only have a center point.