Vicky Wolf

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PALSAR Access at ASF DAACProcedures and Tools
for Accessing and Using PALSAR Data from ASF

• Vicky Wolf
• ASF User Services

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Outline

• Data Acquisition
• Data Search and Ordering
• Subscription procedure
• Tools Available from ASF

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Acquisition vs Observation

• Observations occur when data is collected using
  the recorder or transmitted to JAXA via the relay
  satellite
• Acquisitions occur when data is received in real
  time by an international ground station such as
  the ASF STGS
• PALSAR acquisitions occur in only ScanSAR mode or
  the Direct Downlink mode
• Direct Downlink mode is similar to Fine
  Resolution single polarization mode but has a
  lower resolution (20m vs 10m)

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Data Observation Strategy

• Basic Observation Strategy for ALOS established
  by JAXA
• Observations are balanced among the three sensors
  the satellite carries PRISM, AVNIR-2, and PALSAR
• Data from all three sensors is available from the
  AADN, only PALSAR is available through the USGRC
• The PALSAR observation strategy features routine
  observations using four pre-selected sensor modes
• The PALSAR strategy is separated into one plan
  for ascending (evening) passes, and one for
  descending (morning) passes.
• Most PALSAR observations are planned to be
  ascending to minimize conflicts with optical
  sensors, it is difficult to get descending PALSAR
  coverage with the fine beam modes

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PALSAR SENSOR
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JAXA PALSAR Strategy

• The minimum requirement for any land area on
  Earth is to perform at least one single-pol and
  one dual-pol acquisition annually, and in
  addition, two dual-pol acquisitions during
  consecutive 46-days cycles on a bi-annual basis
  to enable interferometric applications. Most
  areas are however to be acquired significantly
  more often than this, typically 3-5 times per
  year.
• In general, regions in the eastern hemisphere
  (Asia, Australia, eastern Europe and Africa)
  within the coverage of the Data Relay Satellite
  (DRTS) are acquired most frequently, while the
  western hemisphere (the Americas, western Europe
  and Africa) is restrained by the recording and
  down-link capacity of the on-board data recorder
  (HSSR).
• Complete information on regions and modes for
  each cycle can be found at http//www.eorc.jaxa.jp
  /ALOS/obs/overview.htm.

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PALSAR Systematic Observation Strategy-Overview
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PALSAR for Cycle 20 June 9 to July 25, 2008
Fine Beam Dual-Pol ascending coverage of the blue
regions is the plan from the basic observation
strategy for Cycle 20 this summer
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User Driven Observations

• User driven requests have the highest success
  rate when in line with the strategy for a cycle
• For example, it is difficult to successfully
  acquire quad-pol data during cycles that are
  focused on acquiring dual-pol data
• ASF plans user requests two weeks in advance of
  the observation week
• Requests are submitted to JAXA on a weekly basis
• Requests are necessary for acquisitions (direct
  downlinks to ASF)

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PALSAR Observation Scheduling Success
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Data Search and Order

• AADN Americas ALOS Data Node
• Automatically receives all scenes acquired over
  North, South and Central America since ALOS went
  operational from JAXA and makes them visible
  through the AADN URSA
• URSA User Remote Sensing Access interface
• ASF search and order interface
• Two versions exist, one for searching the DAAC
  catalog, the other for searching the AADN catalog
• AUIG JAXAs interface for searching the catalog
  of all known ALOS observations
• Out-of-zone Scenes that are acquired for any
  region of the world other than the Americas or
  prior to the operational phase of ALOS

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PALSAR Scenes in the DAAC

• Scenes in AADN archive are ordered for transfer
  to the DAAC when requested by approved users
• Out-of-zone scenes are ordered for transcription
  from JAXA when requested by approved users
• All PALSAR scenes in the DAAC archive can be seen
  and ordered by approved users
• All PALSAR scenes that have been processed by the
  DAAC are available from the PALSAR datapool
• Subscriptions can be established by approved
  users for transfer and processing by the DAAC

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Searching for Data

• The ASF URSA interface should be used to identify
  scenes for transfer from the AADN archive
• The AUIG interface should be used to identify
  out-of-zone scenes for transcription and transfer
  to the DAAC
• The DAAC URSA interface should be used for
  ordering scenes for processing

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Out-of-Zone Data

• Out-of-zone scenes are scenes that were acquired
  for areas outside of the Americas or prior to the
  operational phase of ALOS
• Out-of-zone scenes are identified by searching
  the AUIG
• To request an out-of-zone scene, a user needs to
  send ASF the scene id and date of observation
• On average, there are 9 days between placing an
  out-of-zone order with JAXA and receiving the
  data for the AADN archive
• When requesting out-of-zone data for DAAC
  projects, USO orders the scenes for transfer as
  soon as they appear in the AADN catalog

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JAXA Archive

• Global archive
• Guest may search all PALSAR holdings
• Commissioning phase data (May 15-Oct 22, 2006)
• Scene ID and date required for OOZ order
• https//auig.eoc.jaxa.jp/auigs/top/TOP1000Init.do

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AADN Archive

• https//ursa.aadn.alaska.edu/
• Guests can search all PALSAR holdings in the AADN
  archive
• Data over the Americas acquired since October 23,
  2006
• Some global data
• Scene IDs are required to designate data for
  transfer

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Data Order

• Data credits awarded by proposal approval are
  only valid for PALSAR data processing
• Investigator logs into URSA DAAC and orders
  scenes for processing to desired parameters
• Processed data is automatically entered into the
  USGRC PALSAR Data Pool in addition to being
  delivered to investigator

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Interfaces

• AADN URSA https//ursa.aadn.alaska.edu/cgi-bin/lo
  gin/guest/
• DAAC URSA https//ursa.asfdaac.alaska.edu/cgi-bin
  /login/
• AUIG https//auig.eoc.jaxa.jp/auigs/top/TOP1000In
  it.do

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Order Processing

• Users may order scenes for processing once they
  are transferred to DAAC
• All PALSAR scenes processed by the DAAC are
  available through the PALSAR datapool

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Subscription Procedure

• User defines either the region or paths and
  frames that are desired
• ASF searches for scenes that match at regular
  intervals and transfers them to the DAAC archive
• ASF either notifies the user that the scenes are
  available to be ordered for processing, or orders
  the scenes for the user based on parameters such
  as processing level and delivery method that the
  user has predefined
• Once processed, scenes are available to all
  approved users through the PALSAR data pool

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ASF User Tools

• USGS Webinar
• 25 April 2008

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MapReady

• Freely available software (BSD license).
• Developed with an intention to increase the
  usability of SAR data.
• Intuitive user interface enables those with
  little or no SAR experience to readily process it
  for use with other data layers.

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MapReady

• Ingests ASF, CEOS, and GeoTIFF data formats.
• Can export the data to JPEG, GeoTIFF, PNG, and
  some other formats.
• Geocodes data to any of five popular map
  projections
• UTM, Polar Stereographic, Lambert Azimuthal Equal
  Area, Lambert Conformal Conic, Albers Equal Area
• Terrain corrects (orthorectifies) to remove
  artifacts commonly seen in SAR data such as
  layover and shadow.

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MapReady

• Includes support for multiband data such as
  polarimetric data.
• Batch processing ability allows users to process
  large volumes of data at once.
• Preview images are visible for each item in the
  batch list (input and output).
• Includes a metadata viewing tool.
• Input and output images can be viewed in full
  resolution with the integrated ASF View tool.
• Image footprint can be viewed in Google Earth.

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MapReady

• Goals for the near future
• Support for Single Look Complex data.
• Improved support for polarimetric data.
• Ability to ingest and process AirSAR data.
• Ability to ingest and process data written by the
  Gamma software.

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Convert to Vector

• This simple tool allows users to create a shape
  or kml file based on images that may not be
  viewable but have metadata.
• The areas footprint can then be viewed using
  Google Earth or ArcMap.
• Non-lat/lon metadata is passed along as
  attributes.
• Windows release planned for May 1st.
• Pending testing validation.

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Convert to Vector
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ASF Forum

• ASF hosts an online forum for users to ask
  questions of our technical staff and user
  community.
• Over 165 members
• Nearly 600 total posts and growing
• https//forum.asf.alaska.edu

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uso_at_asf.alaska.edu 907-474-6661