# Presentation: 259485

## 
LDCM Data Products
Initial Thoughts and Considerations

John Dwyer
SAIC*
US Geological Survey Center for Earth Resources Observation and Science
* Work performed under U.S. Geological Survey contract 03CRCN0001

- LDCM Data Products
- Initial Thoughts and Considerations
- John Dwyer
- SAIC*
- US Geological Survey Center for Earth Resources Observation and Science
- * Work performed under U.S. Geological Survey contract 03CRCN0001

- LDCM Status

## LDCM Data Products

**Assumptions**
- Standard Product
- L1Gt product generated routinely (fixed recipe)
- Processing may be constrained by percent cloud cover
- Geolocation accuracy achieved using definitive ephemeris
- Relief displacement corrected using best available DEM
- Web-enabled access for electronic retrieval
- User-specified products
- Products generated on-demand by user request
- Need to solicit input from the user community on the levels of processing and service that are required
- What products does the community need?
- How are these needs met most effectively?
- Publish data in compliance with standards and protocols for web services
- Need to address consistency with legacy Landsat products
- Includes L1Gt generated from archive according to user-specified parameters
- Includes standard product delivered on hard media

- LDCM Status

## LDCM Standard Data Products

**L0R**
- Some low level product must be available, specifics are TBD
- Demand may not be high, but the requirement may be for CalVal, International Cooperator data inter-comparison, researchers, or value-added retailers (VARs) and service providers
**L1Gt**
- WRS-2 Path/Row
- Surface reflectance preferred, at sensor reflectance at a minimum
- GIS-ready format
- Must be able to provide access to large number of users and high volumes of data

- LDCM Status

## LDCM User-Specified Products

**Potential Product Options**
- Scene-based L1Gs from archive
- at-sensor radiances or at-sensor reflectance; surface temperature/emissivity
- Scene-based L1Gt from archive
- at-sensor radiances, at-sensor reflectance, or surface reflectance; surface temperature/emissivity
- Scene-based cloud reduced composite from standard L1Gt product
- Comprised of at-sensor radiances, at-sensor reflectance, or surface reflectance; surface temperature/emissivity?
- Scene-based spectral indices from standard L1Gt product
- options to derive from single-scene at-sensor radiances or reflectance, surface reflectance, surface temperature/emissivity or cloud reduced composite?

- LDCM Status

## LDCM User-Specified Products

**Potential Product Options (cont’d)**
- Mosaics (contiguous WRS-2 paths/rows)
- At-sensor radiance
- At-sensor reflectance
- Surface reflectance
- surface temperature/emissivity
- Cloud-reduced composites
- Spectral indices
- Area of Interest (AOI)
- User-defined area of interest (uploaded “shapefiles)
- “Data Cubes”
- Based on WRS-2 path/row
- L1Gt with common projection and resampling
- “Change Products”
- Derived using at-sensor reflectance
- Geographic extent may be single WRS-2 path/row, mosaic, or area of interest (AOI)
- Need to define a change metric
- Robustness and measure of uncertainty

- LDCM Status

## Metadata and Distribution Models

**Enabling Data Discovery, Access, and Delivery**
- Metadata model
- Web-enabled search, discovery, and data delivery
- Scene-based metadata (product and pixel-level)
- Registration accuracy
- Uncertainties associated with parameter retrievals
- Date indices, cloud, shadow, snow, land, water, other QC information as additional data layers
- Format options
- File size constraints
- Usability (GIS-ready)
- Data delivery mechanisms
- Electronic retrieval and media options
- Bulk order considerations
- Web services (e.g. Open Geospatial Consortium standards and service protocols)

- LDCM Status

## Product Types

| Acquisitions | Standard | User-specified |
| --- | --- | --- |
| Off-nadir acquisition | yes | yes |
| Nadir acquisition | yes | yes |
|   |   |   |
| Product Types (Levels of Processing) |   |   |
| Level-0R | X | X |
| Level-1R |   |   |
| Level-1Gs |   | X |
| Level-1Gt | X | X |
| At-sensor radiances |   | X |
| Top of Atmosphere Reflectance |   | X |
| Surface Reflectance | X | X |
| Surface Temperature/Emissivity |   | X |
| Spectral Indices |   | X |
| Scene-based Mosaics |   | X |
| Area of Interest (AOI) |   | X |
| Cloud Reduced Composites |   | X |
| Time-series (data cube) |   | X |

- LDCM Status

## Product Characteristics

| Product Characteristics | Standard | User-specified |
| --- | --- | --- |
| Expedited Production | no | yes |
| Datatype | 16-bit | 16-bit |
| Quality Control Layer (TBD), i.e. cloud, shadow, snow, bad data | yes | yes |
| Map Projection | UTM | UTM, TM, Albers Equal Area, SOM-B, Lambert Conformal Conic,Polar Stereographic,Polyconic, OMA, OMB |
| Horizontal Datum | WGS84 | WGS84, NAD83, NAD27, Other |
| Resampling Methods | cubic convolution (CC) | cubic convolution (CC)bilnear interpolation (BL)nearest neighbor (NN)modulation transfer function (MTF) |
| Image Orientation | Map | MapPath (satellite/nominal) |
| Pixel Size | native (15m, 30m, 60m) | user-specified |
| Multi-scene | no | yes |
| Scene-shift | no | yes |
| Format | Geotiff | GeotiffHDF |
| Media | FTP | FTP, DVD, Hard drive |

- LDCM Status