Coastal Services Center

Summary

Different Data Products

Point to the names below to view the different data products.

Applied Uses

Examples of how Landsat data are being used:

Green-Space/Conservation Planning The Endangered and Nongame Species Program (ENSP) of the New Jersey Division of Fish and Wildlife incorporated land cover data (derived from Landsat TM imagery), land use data, and an assortment of ancillary data into a geographic information system (GIS) to rank the relative value of critical habitats. This information was used to help the state decide how to best allocate its resources to protect critical habitats at risk from development.

Controlling Runoff The New York Department of State utilized land cover data derived from Landsat TM to develop a pollution potential model for the Carmans River, Long Island, New York. The model predicted the quantity and intensity of runoff based on the land cover class, slope of the land, and soil type.

Other Potential Uses:

• Land Cover and Change Data
  • Timber Stand Maps for Resource Management
  • Agriculture Maps for Land Management
  • Population Growth Projections
• Input to Global Change Monitoring (Earth Science Enterprise)
• Snow and Ice Melt Potential Models
• Geologic/Mineral Resource Maps (and Petroleum Prospecting)

Specifications

* - ETM+ Band 6 (Thermal IR) includes both high and low gain settings.
** - ETM+ Band 8 (Panchromatic) - most visible & near-IR data in single band.

Temporal Resolution – 16-day sun-synchronous orbits
Landsats are polar-orbiting satellites which will record data for any given spot on Earth every 16 days at approximately the same time of day, which has typically been midmorning. The two active satellites, Landsats 5 & 7, have been counter-synchronized so that they provide data for any given area on the Earth every 8 days.

Swath Width – 185 kilometers wide
The data are continuous and do not have northern or southern cutoffs, but it is distributed in roughly square footprints of 183 km x 170 km.

Data Ordering Details

Data Acquisition	TM and ETM+ data are available through the EROS Data Center (EDC). Some commercial resellers offer TM and ETM+ data with enhanced spatial accuracy, added by their own various image processing techniques. more info
Timing	Depending on the level of processing being ordered (basic to terrain corrected) delivery can take anywhere from a few days to a few weeks. The time could be significantly longer if certain weather or seasonal conditions are required.
Cost	There is small processing fee for all requests. The basic cost structure is based on the level of spatial and/or spectral correction ordered.
Data Formats/Software Needed	The data are normally delivered in formats that require image processing software with importing functions. The data are also available in GeoTIFF format that can be read by standard image viewing programs (such as Adobe Photoshop, Windows Imaging, etc.), although these software packages may have limitations on spatial functions, such as spatial queries and properly displaying files. more info
Projections	The data are available in a number of projections and datums,depending on the user's needs. The standard delivery projection for Precision or Terrain Corrected data is UTM (Universal Transverse Mercator), using GRS 1980 spheroid and NAD83 datum.
Licensing	Once a scene has been purchased from the United States Geological Survey, it can be redistributed as desired.

Frequently Asked Questions

Data Acquisition

Who produces the data?
Landsat 7 ETM+ (Enhanced Thematic Mapper) data are produced by the National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS). Primary data collection and distribution is handled by the USGS EROS (Earth Resources Observation Systems) Data Center (EDC) in Sioux Falls, South Dakota.

Landsat 5 TM (Thematic Mapper) data are also collected by EDC, which maintains an extensive archive of TM images from Landsats 4 and 5. The platform has been operated by USGS since 2001.

Can I request data from the Web? Can I download the data on-line? What media formats are the data delivered on?
TM and ETM+ data can be ordered through several Web sites. Most sites offer the ability to download the data using FTP (file transfer protocol), as well as offer standard delivery on either CD-ROM or 8 millimeter tape:

Data Formats/Software Needed

What types of software are required?
Most image processing platforms (ERDAS Imagine®,PCI Geomatica®, ENVI®, IDRISI®, etc.) can import a variety of image formats, including those used for distribution of TM and ETM+ data. Common GIS programs, such as ArcView, require the raw data to be converted to a compatible format.

Is freeware available for using these data?
Some freeware software packages allow viewing of these data, and some extensions for common software packages will allow you to view and have some limited functions for working with the data. However, if your intent is to manipulate or derive products using spatial data information, you will likely need to use a software package with higher capabilities.

General Questions

Can a GIS technician with some remote sensing experience pick up these data sets and use them?
The data can be viewed easily, using GIS or remote sensing software; however, interpretation may require additional training in remote sensing fundamentals.

Do these data require a trained technical person to analyze the data?
That depends on the extent to which the data are to be analyzed. Most GIS technicians can delineate basic features from the imagery without any remote sensing or photogrammetry knowledge. Detailed classifications and analyses, such as vegetation identification, will likely require additional training or the hiring of remote sensing-trained personnel.

Are there some nuances with the data that could really slow you down?
Occasionally the data can have quality problems. The most typical manifestations are data noise and data drops. Sources of high radiation such as fires and volcanoes can saturate a sensor or cause temporary interference after the sensors receive the high radiation.

What are the limitations of TM and ETM+ data?
These data cannot be used in lieu of high-resolution imagery. Because the pixel size is 30 meters, the data should not be used for legal issues, such as permitting and parcel mapping, or for small feature identification. Landsat data are intended for regional land characterization.

The data archives are sparse for the late 80s and early 90s. During this period, Landsat 4/5 TM data were collected only when requested.

For more Information