CIDR Request Data – Imaging Requirements

The Request Data (link in the Menu bar) tool provides the option to assist U.S. Federal Civil agencies to enter near-term land remote sensing data requirements and provides an interface to place new Data Acquisition Requests (DARs).  There are four sections within Request Data to acquire the desired data. Click information icon for more definitions/information per entry box. (Figure 1)
The requirements for requesting data:

A. Request Details
B. Imaging Requirements
C. Spatial Requirements
D. Submit Request

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Figure 1:  Request Data Tool
 

B. Imaging Requirements – Enter the specific information pertaining to the request. As each option is chosen, they will determine the follow-on options.   (Figure 2)

• Type of Sensor
• Type of Product
• Acquisition Start
• Acquisition End
• Collection Strategy (But Not Guaranteed)
• Publicly Viewable DAR
• Spacecraft (Optional)
• Processing Level (Optional)
• Output Format (Optional)
   

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Figure 2: Imaging Requirements
 

Type of Sensor – Choose the type of sensor that will meet project requirements. 

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Figure 3: Sensors Options

Electro-optical (EO) imagery captures photographic stills using a high-resolution camera or sensor that passively detects and records the magnitude and color of emitted or reflected light, converting it into pixels.  List of advantages and limitations of (EO)

• Advantages
  • Natural-looking imagery: EO images are visually intuitive and readily interpreted by humans.
  • High spatial resolution: EO satellites can achieve very high spatial resolutions, capturing detailed features.
  • Multispectral and hyperspectral capabilities: EO sensors can capture data across multiple spectral bands, providing information beyond what the human eye can see.
• Limitations
  • Weather dependent: Cloud cover, fog, smoke, and other atmospheric conditions can significantly reduce the usefulness of EO imagery.
  • Daylight restriction: EO satellites are unable to capture images at night, limiting their ability to monitor nighttime activities.
  • Surface reflectivity: EO images are influenced by the reflectivity of the surface, which can vary depending on factors like sun angle and material properties. 

Synthetic Aperture Radar (SAR) imagery provides radar images of the Earth's surface by actively sending out radar waves and analyzing the reflected signals. These images are useful because they can penetrate clouds and darkness, offering all-weather, 24/7 imaging capabilities. SAR data is used for various applications like mapping, monitoring, and detecting changes on the Earth's surface. List of advantages and limitations of (SAR)

• Advantages
  • All-weather imaging: SAR can penetrate clouds, smoke, and fog, making it ideal for monitoring areas where weather conditions are often problematic.
  • Nighttime imaging: SAR can operate at night, allowing for 24/7 monitoring.
  • Surface roughness and moisture information: SAR is sensitive to the roughness and moisture content of the Earth's surface, providing valuable insights into land cover, vegetation, and even subsurface features.
  • Ground movement detection: SAR can detect subtle ground deformation, useful for monitoring land subsidence, landslides, and other geohazards.
  • Interferometric SAR (InSAR): SAR data can be used to create interferograms, which are maps of relative elevation changes, enabling precise measurements of deformation.
• Limitations
  • Monochromatic: SAR images are typically grayscale, which can make them more difficult to interpret for some applications.
  • Speckle noise: SAR images often contain speckle noise, which can be a source of artifacts.
  • Resolution: SAR resolution can be lower than EO, depending on the specific radar frequency and sensor configuration. 

The list of Commercial Satellites available for Electro-Optical (EO) and Synthetic Aperture Radar (SAR)

Type of Product – Choose from the different types of remote sensing imagery options: 

• Electro-Optical (EO)
  • MSI+PAN (Multispectral + Panchromatic) - Multispectral imagery captures multiple narrow bands of the electromagnetic spectrum, providing information about the spectral reflectance of the Earth's surface. Panchromatic imagery captures a wider band, typically the entire visible spectrum and near-infrared, resulting in a single-band image with higher spatial resolution.
  • MSI (Multispectral) -- A collection of a few image layers of the same scene, each of them acquired at a particular wavelength band.
  • PAN (Panchromatic) -- involves capturing images with a broad band of the electromagnetic spectrum, resulting in black and white images with high spatial resolution.
  • SWIR (Short-Wave Infrared Satellite Imagery); Detect Heat. Identify hotspots from wildfires, penetrates smoke, volcanic activity or man-made heat sources

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Figure 4: EO Imagery Options

• Synthetic Aperture Radar (SAR)
  • VV (Vertical transmits Vertical receives) – Sensor transmits and receives a vertically polarized signal.  Polarization refers to the orientation of the electromagnetic wave's electric field.
  • HH (Horizontal transmits Horizontal receives) – Sensor transmits and receives a horizontally polarized signal.  Polarization refers to the orientation of the electromagnetic wave's electric field.
  • Dual VV+HH or HH+VV -- Dual-polarization data where the SAR sensor transmits and receives radar signals in both Vertical-Vertical (VV) and Horizontal-Horizontal (HH) polarizations.  The first designation is the transmit direction and the second is receive.
  • Quad HH+VV+HV+VH – Quad polarization transmits and receives in both polarizations. 

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Figure 5: SAR Imagery Options

Acquisition Start – Enter desired collection start date of imagery.  Enter date that is 24 to 48 hours after entering request.  i.e. Don’t enter a date for the same day entering request. Also, the start date is only relevant for new collections.  If requesting archived data, entering a date does not affect the collect.  

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Figure 6: Acquisition Start Date

Acquisition End – Enter desired collection end date of imagery. The stop date should be no longer than one year past the start date.  If users need to go beyond the one-year timeframe another DAR would have to be submitted. 

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Figure 7: Acquisition End Date

Collection Strategy (But Not Guaranteed) – Users request the desired frequency of collection attempts.  Even though collection frequency is requested does not guarantee the imagery will be collected.  The Collection Strategies are guidelines and not strict rules. The strategy also depends on the size of area and frequency of the passes.  The recommendation is to use the fields as a starting point and put the actual project needs within the Project Description.  Within the Request Data section, there are several text fields, users can indicate and special collects or other information in those fields. Collection Strategy options are: 

• Archived -- The user wants past imagery and should use the Archive and Scene List options in the Request Detail Section or enter info in the Additional Information text area.
• One Good Collect – One good collect mostly cloud free over the requested period.
• 1 in 1 for 7 days (up to 90% cloud cover) – Option indicates one attempt per day for seven days.
• 1 in 3 for 21 days (up to 50% cloud cover) – One attempt every three days for 21 days.
• 1 in 7 for 42 days (up to 25% cloud cover) – One attempt every seven days for 42 days.
• 1 in 15 for 90 days (up to 25% cloud cover) -- One attempt every 15 days for 90days (3 months).

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Figure 8: Collection Strategy Options

Publicly Viewable – Yes/No option indicates whether requestors allow the viewing of a DAR Area of Interest (AOI) to other CIDR users or considered private.  Basically, show the footprint or not show the footprint.  Allow DAR to be copied and exported.

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Figure 9: Publicly Viewable Options

Spacecraft (Optional) – If users require a preference for specific spacecraft, it can be selected here. The list of options depends on the Type of Sensor and Type of Imagery selected.

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Electro-optical Sensor Options                                                                                         

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  SAR Options

Processing Level (Optional) – This option only applies to MAXAR data (WV1, WV2, WV3) being distributed through EarthExplorer.  If choosing something other than MAXAR data, disregard this selection.

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Figure 10: Processing Level Options

Output Format (Optional) -- This option only applies to MAXAR data (WV1, WV2, WV3) being distributed through EarthExplorer.  Recommendation is to choose the NTF format.  If choosing something other than MAXAR data, disregard this selection.

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Figure 11: Output Format Options