LandsatLook Viewer

Welcome to the LandsatLook Viewer! The LandsatLook Viewer is a prototype tool that was developed to allow rapid online viewing and access to the USGS Landsat image archives. This viewer allows you to: Interactively explore the Landsat archive at up to full resolution directly from a common web browser Search for specific Landsat images based on area of interest, acquisition date, or cloud cover Compare image features and view changes through time Display configurable map information layers in combination with the Landsat imagery Create a customized image display and export as a simple graphic file View metadata and download the full-band source imagery Search by address or place, or zoom to a point, bounding box, or Sentinel-2 Tile or Landsat WRS-1 or WRS-2 Path/Row Generate and download a video animation of the oldest to newest images displayed in the viewer We welcome feedback and input for future versions of this Viewer! Please provide your comments or suggestions . About the Imagery This viewer provides visual and download access to the USGS LandsatLook "Natural Color" imageproduct archive. Background The Landsat satellites have been collecting multispectral images of Earth from space since 1972. Each image contains multiple bands of spectral information which may require significant user time, system resources, and technical expertise to obtain a visual result. As a result, the use and access to Landsat data has been historically limited to the scientific and technical user communities. The LandsatLook “Natural Color” image product option was created to provide Landsat imagery in a simple user-friendly and viewer-ready format, based on specific bands that have been selected and arranged to simulate natural color. This type of product allows easy visualization of the archived Landsat image without any need for specialized software or technical expertise. LandsatLook Viewer The LandsatLook Viewer displays the LandsatLook Natural Color image product for all Landsat 1-8 images in the USGS archive and was designed primarily for visualization purposes. The imagery within this Viewer will be of value to anyone who wants to quickly see the full Landsat record for an area, along with major image features or obvious changes to Earth’s surface through time. An area of interest may be extracted and downloaded as a simple graphic file directly through the viewer, and the original full image tile is also available if needed. Any downloaded LandsatLook image product is a georeferenced file and will be compatible within most GIS and Web mapping applications. If the user needs to perform detailed technical analysis, the full bands of Landsat source data may also be accessed through direct links provided on the LandsatLook Viewer. Image Services The imagery that is visible on this LandsatLook Viewer is based on Web-based ArcGIS image services. The underlying REST service endpoints for the LandsatLook imagery are available at https://landsatlook.usgs.gov/arcgis/rest/services/LandsatLook/ImageServer . Useful linksLandsat- Landsat Mission (USGS)- Landsat Science (NASA)LandsatLook- Product Description- USGS Fact Sheet- LandsatLook image services (REST)Landsat Products- Landsat 8 OLI/TIRS- Landsat 7 ETM+- Landsat 4-5 TM- Landsat 1-5 MSS- Landsat Band Designations LandsatLook images are full-resolution files derived from Landsat Level-1 data products. The images are compressed and stretched to create an image optimized for image selection and visual interpretation. It is recommended that these images not be used in image analysis. LandsatLook image files are included as options when downloading Landsat scenes from EarthExplorer, GloVis, or the LandsatLook Viewer (See Figure 1). Figure 1. LandsatLook and Level-1 product download options LandsatLook Natural Color Image The LandsatLook Natural Color image is a .jpg composite of three bands to show a “natural” looking (false color) image. Reflectance values were calculated from the calibrated scaled digital number (DN) image data. The reflectance values were scaled to a 1-255 range using a gamma stretch with a gamma=2.0. This stretch was designed to emphasize vegetation without clipping the extreme values. Landsat 8 OLI = Bands 6,5,4 Landsat 7 ETM+ and Landsat 4-5 TM = Bands 5,4,3 Landsat 4-5 MSS = Bands 2,4,1 Landsat 1-3 MSS = Bands 7,5,4 LandsatLook Thermal Image The LandsatLook Thermal image is a one-band gray scale .jpg image that displays thermal properties of a Landsat scene. Image brightness temperature values were calculated from the calibrated scaled digital number (DN) image data. An image specific 2 percent clip and a linear stretch to 1-255 were applied to the brightness temperature values. Landsat 8 TIRS = Band 10 Landsat 7 ETM+ = Band 61-high gain Landsat 4-5 TM = Band 6 Landsat 1-5 MSS = not available LandsatLook Quality Image LandsatLook Quality images are 8-bit files generated from the Landsat Level-1 Quality band to provide a quick view of the quality of the pixels within the scene to determine if a particular scene would work best for the user's application. This file includes values representing bit-packed combinations of surface, atmosphere, and sensor conditions that can affect the overall usefulness of a given pixel. Color mapping assignments can be seen in the tables below. For each Landsat scene, LandsatLook Quality images can be downloaded individually in .jpg format, or as a GeoTIFF format file (_QB.TIF) within the LandsatLook Images with Geographic Reference file. Landsat Collection 1 LandsatLook 8-bit Quality Images Designations Landsat 8 OLI/TIRS Landsat 7 ETM+, Landsat 4-5 TM Landsat 1-5 MSS Color Bit Description Bit Description Bit Description 0 Designated Fill 0 Designated Fill 0 Designated Fill 1 Terrain Occlusion 1 Dropped Pixel 1 Dropped Pixel 2 Radiometric Saturation 2 Radiometric Saturation 2 Radiometric Saturation 3 Cloud 3 Cloud 3 Cloud 4 Cloud Shadow 4 Cloud Shadow 4 Unused 5 Snow/Ice 5 Snow/Ice 5 Unused 6 Cirrus 6 Unused 6 Unused 7 Unused 7 Unused 7 Unused Unused Table 1. Landsat Collection 1 LandsatLook 8-bit Quality Images Designations LandsatLook Images with Geographic Reference The LandsatLook Image with Geographic Reference is a .zip file bundle that contains the Natural Color, Thermal, and the 8-bit Quality images in georeferenced GeoTiff (.TIF) file format. Figure 2. LandsatLook Natural Color Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013 Figure 3. LandsatLook Thermal Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013 Figure 4. LandsatLook Quality Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013 with background color set to dark grey. Additional Information About LandsatLook Images Many geographic information systems and image processing software packages easily support .jpg images. To create these files, Landsat data is mapped to a 1-255 range, with the fill area set to zero (if a no-data value is set to zero, the compression algorithm may introduce zero-value artifacts into the data area causing very dark data values to be displayed as no-data).