Landsat

Geoscientific Mineral ResourcesLANDSAT General Overview

First launched in 1972, the LANDSAT satellite series constitutes one of the longest continuous records in Earth observation. The objective of the LANDSAT program has always been to provide multi-spectral imagery of the Earth's land areas at moderate to high resolution, (28.50 - 90.00 meter horizontal resolution) to support resource assessment, land-cover mapping, and to track inter-annual changes in the environment.

Applications of LANDSAT data are quite diverse, comprising Earth Science, commercial applications, mining applications, government and military use. A few examples include mapping land-cover change (forest change, urbanization, etc), monitoring agricultural productivity, monitoring wetland health, mapping geologic resources, and targeting habitats for vector-borne disease eradication. LANDSAT is a cornerstone of NASA's Earth Observing System, providing moderate-resolution to high-resolution images.

Sensors

  • Multi-spectral Scanner (LANDSAT MSS)
    The MSS was a cross-track, (whiskbroom), scanner that acquired imagery in four channels (2 visible, 2 near-infrared) at 79.00-meter resolution. The MSS was included on Landsat-1 through Landsat-5.

  • Thematic MAPPER (LANDSAT TM)
    The MSS was a cross-track, (whiskbroom), scanner that acquired imagery in four channels (2 visible, 2 near-infrared) at 79.00-meter resolution. The MSS was included on Landsat-1 through Landsat-5.

  • Enhanced Thematic MAPPER Plus (LANDSAT ETM+)
    The ETM+ instrument currently flying on Landsat-7 is similar to the earlier TM, but adds an extra 14.25-meter resolution panchromatic band, and improved resolution for the thermal-infrared band (57.00-meters).

LANDSAT Technical Guide

Overview

LANDSAT imagery is relatively high-resolution earth observation data that is acquired through sensors on one of the NASA LANDSAT satellites. The satellite sensors acquire high integrity images of the planet surface in a systematic fashion. Users can take this imagery and use it to determine the health and type of vegetation, amount of built surfaces, success of agriculture, or apply it for a myriad other uses like various geological derived applications as well as various mineral exploration activities.

Table 1

Orbit and Acquisition Characteristics

Satellite Sensor Swath (km) Scene Size (km) Altitude (km) Revisit (days)
LANDSAT 1-5 MSS 180 180 x 170 917 18
LANDSAT 4-5 TM 185 170 x 183 705 18
LANDSAT 7 ETM+ 185 170 x 183 705 16

Table 2

Spectral Resolutions & Spatial Resolutions

Satellite Spectral Resolution () Band Spatial Resolution
LANDSAT 1-3 MSS   (Meters)
  Band 4: 0.50 - 0.60 Green 79.00 Meter Resolution
  Band 5: 0.60 - 0.70 Red 79.00 Meter Resolution
  Band 6: 0.70 - 0.80 Near IR 79.00 Meter Resolution
  Band 7: 0.80 - 1.10 Near IR 79.00 Meter Resolution
LANDSAT 4-5 MSS    
  Band 4: 0.50 - 0.60 Green 82.00 Meter Resolution
  Band 5: 0.60 - 0.70 Red 82.00 Meter Resolution
  Band 6: 0.70 - 0.80 Near IR 82.00 Meter Resolution
  Band 7: 0.80 - 1.10 Near IR 82.00 Meter Resolution
  TM    
  Band 1: 0.45 - 0.52 Blue 30.00 Meter Resolution
  Band 2: 0.52 - 0.60 Green 30.00 Meter Resolution
  Band 3: 0.63 - 0.69 Red 30.00 Meter Resolution
  Band 4: 0.76 - 0.90 Near IR 30.00 Meter Resolution
  Band 5: 1.55 - 1.75 Mid IR 30.00 Meter Resolution
  Band 6: 10.4 - 12.5 Thermal 120.00 Meter Resolution
  Band 7: 2.08 - 2.35 Mid IR 30.00 Meter Resolution
LANDSAT 7 ETM+    
  Band 1: 0.450 - 0.515 Blue 28.50 Meter Resolution
  Band 2: 0.525 - 0.605 Green 28.50 Meter Resolution
  Band 3: 0.630 - 0.690 Red 28.50 Meter Resolution
  Band 4: 0.760 - 0.900 Near IR 28.50 Meter Resolution
  Band 5: 1.550 - 1.750 Mid IR 28.50 Meter Resolution
* Band 6: 10.40 - 12.5 Thermal 57.00 Meter Resolution
  Band 7: 2.080 - 2.35 Far IR 28.50 Meter Resolution
  Panchromatic    
  Band 8: 0.52 - 0.92 Pan 14.25 Meter Resolution

* Note: Band 6 on LANDSAT 7 is divided into two bands, high and low gain.

Imagery from the LANDSAT satellites has been acquired since 1972, with a variety of characteristics to consider. There have been six operational LANDSAT satellites, with three different useful sensors, all of which are available from Geoscientific Trust. The MSS sensor provides the oldest and lowest quality LANDSAT data and images are available from 1972. The TM sensor has improved quality and images are available from 1984. The ETM+ sensor on the LANDSAT 7 satellite remains the best quality of all the sensors.

Radiometric Characteristics

LANDSAT imagery is acquired in a very precise manner, to better emphasize particular land cover aspects. Some of the parameters of this precision involve a scene's radiometry, providing distinct characteristics to components of the image scene. These measures help determine what the images are good for, from a science perspective. For example, Bands 1, 2 and 3 are used together to approximate how the real world appears. Bands 4, 5 or 7 from ETM+ are used in combination with 1, 2 or 3 to demonstrate vegetation conditions.

Data Format Properties

LANDSAT imagery is provided to the user by Geoscientific in a specific series of formats, all of which are designed for maximum coverage of users who have access to basic graphical software, (please note that we supply two basic software packages to all new clients on a 'no cost basis' when LANDSAT satellite images are ordered from Geoscientific).

Each LANDSAT scene is available with bands as separate files, (.tiff format - split layers / files - BSQ Band Sequential Format). A Geo-TIFF file can be used as a TIFF file in any graphical software, or if the client has spatial software the images will be supplied as either. Tiff or .IMG file extensions.

The geo-reference formats employed by Geoscientific for LANDSAT imagery include a UTM projection and a WGS84 datum and ellipsoid. In addition to this geo-referenced information, all LANDSAT image files acquired from Geoscientific will have been processed using a re-sampling technique, namely 'Cubic Convolution' that greatly enhances the visibility of many ground features.

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