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sat 1. Designed by Virginia T. Norwood, the Multispectral Scanner (MSS) onboard Landsats 1–5
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provided invaluable measurements of the Earth’s surface in both the visible and infrared spectra.
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Although she passed away earlier this year, her legacy as “The Mother of Landsat” lives on, as the
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Landsat program has become the longest-running Earth observation program in history [1].
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The Landsat satellite program stretches over 50 years and includes 9 generations of satellites, each
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with its own set of sensors . Landsats 1–3 carried the Return Beam Vidicon (RBV), an RGB analog
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camera [2]. However, its lower number of spectral bands and electrical issues meant it was rarely
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used for research purposes. Instead, the Multispectral Scanner (MSS) onboard Landsats 1–5 was the
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primary scientific instrument, with a line-scanning and rotating mirror-based camera [3]. Landsats
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4–5 also included the Thematic Mapper (TM), with a greater number of spectral bands (from 4 to 7)
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and finer spatial resolution (from 80 m to 30 m) [4]. Although it failed to reach orbit and eventually
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crashed down to Earth, Landsat 6 would have carried the Enhanced Thematic Mapper (ETM), which
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added a 15 m resolution panchromatic band. Landsat 7 carried the Enhanced Thematic Mapper Plus
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(ETM+), which upgraded the thermal band from 120 m to 60 m resolution [5]. Onboard Landsats
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1https://github.com/microsoft/torchgeo
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Preprint. Under review.arXiv:2306.09424v2 [cs.LG] 22 Oct 2023
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0
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Wavelength ( µm)0
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0.5 1.0 1.5 2.0Landsat 8–9
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(OLI/TIRS)Landsat 7
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(ETM+)Landsat 4–5
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(TM)
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89
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7 65 4
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32187 5 43217 5 4321
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11 12153010015306030120
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Resolution (m)
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11 1066Figure 1: Spectral wavelengths and spatial resolutions of each band captured by the Landsat sensors
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used in our study. Numbers are band indices and colors are for visualization purposes only. As
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each sensor has a different number of spectral bands, spatial resolutions, and wavelengths, it is not
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possible to train a single one-size-fits-all model.
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8–9, the Operational Land Imager (OLI) adds new coastal aerosol and cirrus bands for improved
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cloud masking, while the Thermal Infrared Sensor (TIRS) adds an additional thermal band [6]. See
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Figure 1 for a rundown of the spectral wavelengths and spatial resolutions of the primary sensors of
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interest in our study and Figure 2 for a timeline of when these satellites were active.
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In addition to the differences between sensors onboard each satellite, the United States Geological
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Survey (USGS) distributes several different Landsat products with varying processing levels. Level-
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1 data, also known as Top of Atmosphere (TOA), are images that have undergone registration against
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ground control points (GCPs) and orthorectification against digital elevation models (DEMs). These
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products are particularly useful for cloud masking and other atmospheric applications. Level-2 data
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includes Surface Reflectance (SR) and other products that have undergone atmospheric correction.
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These products are useful for a wide range of land surface applications [7].
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In recent years, there has been significant activity at the intersection of self-supervised learning
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(SSL) and remote sensing (RS) due to the wide availability of petabytes of free, unlabeled satellite
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imagery. An early example of this is Tile2Vec [8], which uses geographic distance between sampled
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patches and a triplet margin loss for contrastive learning. Geography-Aware SSL [9] instead uses
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multiple images occurring at the same geospatial location at different points in time to form positive
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pairs, in combination with an additional subnetwork that tries to guess the latitude/longitude from
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the learned representation. More recently, masked autoencoders have seen a surge in popularity, in-
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cluding SatMAE [10] and Scale-MAE [11]. Other papers instead focus on dataset curation, allowing
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generic SSL techniques from computer vision to be applied. Seasonal Contrast (SeCo) [12] creates
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a new dataset using random Gaussian sampling around cities to diversify the pre-training dataset.
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SSL4EO-S12 [13] further extends this idea by avoiding overlap between image samples.
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Recent review papers [14, 15, 16] targeting the intersection between SSL and RS detail prior work on
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this topic and offer benchmark results on several models and SSL techniques popular in computer
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vision, including MoCo [17], SwA V [18], SimSiam [19], Barlow Twins [20], SimCLR [21], and
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BYOL [22]. Among these, the authors find that although SimCLR and SwA V work well on the
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ImageNet [23] dataset, MoCo and BYOL tend to learn better representations on RS imagery [15, 16].
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Due to their higher spatial resolution and faster repeat period, a lot of recent work, especially in
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the SSL space, focuses on Sentinel-2 [24, 25, 13], Maxar [9, 26, 27], and Planet [28, 29] satellites.
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However, many applications are not suited to these satellites. In particular, applications involving
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long-term trends—including agriculture [30, 31, 32, 33, 34], climate change [35, 36, 37, 38, 39],
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2
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1970 1980 1990 2000 2010 2020987654321Landsat Mission
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Sep 2021–PresentFeb 2013–PresentApr 1999–PresentOct 1993Mar 1984–Jun 2013Jul 1982–Jun 2001Mar 1978–Sep 1983Jan 1975–Mar 1983Jul 1972–Jan 1978Figure 2: Timeline of all Landsat missions. Crosshatched regions represent partial or complete
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sensor failure, including electrical issues with RBV on Landsat 1 and SLC-off on Landsat 7. Each
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bar ranges from launch date to decommissioning date. Note that satellites may be placed in standby
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mode before the decommissioning date, as is the case with Landsat 4.
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deforestation [40, 41, 42, 43, 44], and ecology [45, 46, 47, 48, 49]—require a much longer temporal
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history. While Sentinel-2 has an 8 year history, Landsat’s 50+ year history makes it essential for
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monitoring long-term land surface changes. There are an order of magnitude more papers that use
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Landsat as compared to Sentinel, and Landsat continues to dominate the scientific literature even
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after the launch of Sentinel-2 and MODIS [50]. The United States Geological Survey (USGS)
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estimates that Landsat imagery provides users with an annual benefit of $4.2 billion [51].
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In this work, we further extend the ideas proposed in SeCo [12] and SSL4EO-S12 [13] to the Landsat
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imagery domain. Specifically, we improve on the sampling method of the two previously mentioned
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papers and sample Landsat imagery across the world and across three different sensors and two
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product levels. We pre-train ResNet [52] and ViT [53] models using SimCLR v1 and MoCo v2 on
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each combination of sensor and product to produce a suite of pre-trained Landsat foundation models
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that can be used in downstream tasks. To test these models, we modernize two older datasets based
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on Landsat 7 and 8 imagery, and create several additional crop classification and land cover mapping
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tasks. In summary, the contributions of this paper include:
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• the first ever SSL dataset for the Landsat family of satellites,
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• the largest Landsat dataset in history (1M images per sensor/product, 5M in total),
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• modernized and re-released versions of the L7 Irish and L8 Biome cloud detection datasets,
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• two new benchmark datasets that can be used across all Landsat sensors and product levels,
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• the first ever benchmark datasets for TM and ETM+ SR imagery, and
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• the first ever foundation models pre-trained on Landsat imagery.
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Importantly, all of these SSL techniques, datasets, and pre-trained models are distributed via the
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TorchGeo library [54], allowing for ease of use, experimentation, and reproduciblity.
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2 Datasets
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In this section, we detail our methodology behind the collection of the SSL dataset we create, in-
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cluding differences from prior work. We also introduce the existing and newly created benchmark
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datasets we use to evaluate the representations learned by our pre-trained models.
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3
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2.1 SSL4EO-L pre-training dataset
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For our SSL pre-training dataset, we extend the methodology introduced by Manas et al. [12] and
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refined by Wang et al. [13]. Specifically, we iterate over the following steps:
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1) sample one of the 10K most populous cities in the world [55] uniformly at random;
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2) sample a 264×264px (7.92×7.92km) patch from a Gaussian distribution with a 50 km
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