Time lapse sequence of LandsatLinkr-processed imagery (1974-2014). White indicates missing data at the beginning or end of the time series (the spectral-temporal fitting does not extrapolate).
DEVELOP, part of NASA's Applied Sciences Program, addresses environmental and public policy issues through interdisciplinary research projects that apply the lens of NASA Earth observations to community concerns around the globe. Bridging the gap between NASA Earth Science and society, DEVELOP builds capacity in both participants and partner organizations to better prepare them to address the challenges that face our society and future generations. With the competitive nature and growing societal role of science and technology in today's global workplace, DEVELOP is fostering an adept corps of tomorrow's scientists and leaders.
LLR was used in the following two projects from the NASA DEVELOP node at Colorado State Univeristy, Fort Collins, CO.
MSS data is often overlooked because it has lower spatial and radiometric resolution, and records fewer wavelength bands than its successors (TM, ETM+, and OLI). However, it adds ~12 years of observation (1972-1984) to the Landsat archive for a total of 43+ years of Earth observation data. This record is unparalleled and is approaching an ecologically meaningful length of time to study short-term Earth surface changes. LandsatLinkr makes MSS images relevant and easy to work with by producing synthetic data that matches the qualities and spectral character of TM/ETM+ data. Below is an example of synthetic tasseled cap greenness (similar to NDVI) MSS data that demonstrates its utility for recording phenology in the north eastern US. The time series represents nearly all MSS images that intersect WRS-2 path/row: 014/032. The values are image median post-cloud masking and cropped to WRS-2 path/row: 014/032.
The plot was built with the Plotly.js API, so it is interactive. Click, scroll, hover, and choose options from the Plotly menu.
Area represented by the data in the MSS tasseled cap greenness time series plot above (WRS-2 014/032).
To showcase the results of LLR spectral-temporal calibration, three figures are provided. Figure 1 shows a visual comparison of standard tasseled cap planes for MSS (top row) and TM (bottom row) for a sample of pixel values from a coincident image pair. The shape and density of the scatter plots are very similar, particularly for tasseled cap brightness and greenness, with some disparity for wetness. In a similar example, Figure 2 shows an MSS/TM image pair as tasseled cap brightness, greenness, wetness displayed to the red, green, and blue color guns with the same scaling. Notice the close similarity in visual appearance. Finally, Figure 3 displays a time series of calibrated pixel values at a given coordinate for all images included for an example LLR project. Note the smooth blended transition between sensors at their overlap.
Figure 1. Comparison of the standard Tasseled cap planes for MSS (top row) and TM (bottom row) for coincident images.
Figure 2. Example of MSS (left) and TM (right) tasseled cap indices brightness, greenness, wetness displayed with red, green, and blue color guns for a standardized scale. Note the close similarity between the two coincident image displays.