Below you'll find answers to common questions about USGS Land Change Monitoring, Assessment, and Projection (LCMAP).
- What is LCMAP?
- What is time series modeling?
- What are LCMAP Collections?
- When will LCMAP data be available for Alaska?
- Will previous LCMAP Collections still be available after a new Collection is released?
- Should I still use previously released Collection data after a new Collection is released?
- Where can I find information about the differences between LCMAP Collections?
- Where can I find which Collection of Landsat ARD data was used with which LCMAP Collection?
- What LCMAP products are available?
- What method is used for creating LCMAP Science Products?
- What is the difference between the Primary and Secondary Land Cover products?
- How do I identify model breaks and what they mean?
- Where do I find information about validation and standard errors?
- When will the most recently completed collection be made available?
- How do I search and download LCMAP data?
- Are there any restrictions on the use or redistribution of LCMAP products?
LCMAP stands for Land Change Monitoring, Assessment, and Projection. It represents a new generation of land cover mapping and change monitoring from the U.S. Geological Survey. LCMAP responds to a need for higher quality results at greater frequency and offers more land cover and change variables than previous efforts.
LCMAP Science Products are developed by applying time series modeling to U.S. Landsat Analysis Ready Data (ARD) to detect land surface change.
Harmonic time series models are developed from all available clear Landsat observations on a per-pixel basis using an implementation of the Continuous Change Detection and Classification (CCDC) algorithm (Zhu and Woodcock, 2014).
The time series approach enables the monitoring of annual land cover class conversions, as well as the detection of more subtle, conditional changes on the landscape, while mitigating many challenges associated with land cover mapping efforts, such as cloud cover or phenological cycles.
A new LCMAP Collection occurs when there are changes or refinements to the algorithms, or when the input data is updated.
A major Collection release is generally tied to a fundamental change in the base input data for change detection. For example, LCMAP CCDC 1.x data sets are tied to Landsat Collection 1 Analysis Ready Data (ARD), and LCMAP CCDC Collection 2.x data sets will be tied to Landsat Collection 2 ARD.
Minor dot releases (e.g., LCMAP CCDC 1.2) generally represent algorithm refinements or additional annual products years due to more recent base input data. For example, two additional years of Landsat Collection 1 ARD data were used in LCMAP CONUS Collection 1.1, shifting the provisional year from 2017 (in 1.0) to 2019 (in 1.1).
Methodology modifications for application of time series modeling using the Continuous Change Detection and Classification (CCDC) algorithm (Zhu and Woodcock, 2014) for Alaska are under development, with an anticipated release date no sooner than 2023. Please subscribe to our listserv and follow our social media accounts for updates.
Once a new Collection is released, the previous Collection may no longer be available after a certain period of time. Users should utilize the most recent version of the LCMAP science products regardless of previous product availability. Products from different Collections should not be used together.
For information about Collections visit: LCMAP Collections
Users should use the most recent Collection to ensure that they have the most up-to-date information. Users should not use data from different Collections together.
For information about Collections visit: LCMAP Collections
LCMAP Collections do not necessarily correspond to Landsat ARD collections.
Please visit LCMAP Conterminous United States Data, LCMAP Hawaii Data, or look in the table below to learn which Landsat ARD Collection each LCMAP Collection uses.
Table showing the LCMAP Collection number, the associated Landsat ARD source, the product range, and the release date of the Collection.
|LCMAP Collection||Landsat ARD Source||Product Date Range||Release Date|
|CONUS 1.0||Collection 1 Landsat ARD||1985-2017||June 2020|
|CONUS 1.1||Collection 1 Landsat ARD||1985-2019||April 2021|
|CONUS 1.2||Collection 1 Landsat ARD||1985-2020||November 2021|
|Hawaii 1.0||Collection 1 Landsat ARD||2000-2020||January 2022|
LCMAP includes a suite of 10 science products, reference data, and validation data. Visit the following links to learn more about each dataset.
- LCMAP Collection 1.2 Science Products
- LCMAP Hawaii 1.0 Science Products
- LCMAP Reference Data
- LCMAP Validation Data
LCMAP uses the Continuous Change Detection and Classification (CCDC) algorithm to create its science products.
Learn more about the LCMAP implementation of the CCDC Algorithm:
The Primary Land Cover product indicates the most likely land cover class output by the classification algorithm. The Secondary Land Cover product indicates the second most likely land cover class. Each pixel is assigned a primary and secondary land cover class. The confidence in those assignments is also recorded. The Confidence Products provide useful information for understanding the modeled confidence of primary and secondary classifications. Users should carefully evaluate their needs and requirements when deciding how to utilize these land cover products and their associated confidence values.
Watch the video: Primary & Secondary Land Cover
Model breaks can be identified within the SCTIME and SCMAG products, which will record a non-zero value if there was a detected spectral model break within the calendar year. Examination of additional product values is necessary to determine if the break is associated with a change in land cover. A different LCPRI (primary land cover) code or an LCACHG change code demonstrates that a land cover change took place.
Note that the value of SCTIME will indicate whether the change is recorded in the LCACHG product in the current product year (change on or before July 1st) or the following year (change after July 1st).
Watch the video: Time of Spectral Change & Spectral Change Magnitude
The LCMAP annual land cover and land cover change products were validated using independently collected reference data. The results are presented as confusion matrices and summary tables that can be downloaded from the USGS ScienceBase Data Catalog.
Further details about the reference data, validation efforts, and related publications can be found on the LCMAP Validation website.
New collections will be released as data and processing allows. CONUS Collection 1.2 (1985-2020) was released in November 2021 and CONUS Collection 1.3 (1985-2021) will begin processing in early 2022, once all calendar year 2021 Landsat ARD data are available. Subscribe to the LCMAP Listserv to be the first to know when new Collections are released.
LCMAP products produced by the USGS are available for download at no charge from a variety of sources.
Visit the LCMAP data access page to learn more.
There are no restrictions on LCMAP science products downloaded from the USGS; the data can be used or redistributed as desired. We do request that you include a statement of the data source when citing, copying, or reprinting USGS LCMAP products.
Learn more: USGS Copyrights and Credits statement
A citation for the specific LCMAP Science Product used may be included in publication or presentation materials to acknowledge the USGS as a data source and to credit the original research. The Digital Object Identifier (DOI) can be found on the product page for the specific product that was used (ex: CONUS V1.2: https://doi.org/10.5066/P9SW95Z0)
Visit the LCMAP Data page for details about each product.
Brown, J.F., Tollerud, H.J., Barber, C.P., Zhou, Q., Dwyer, J.L., Vogelmann, J.E., Loveland, T.R., Woodcock, C.E., Stehman, S.V., Zhu, Z., Pengra, B.W., Smith, K., Horton, J.A., Xian, G., Auch, R.F., Sohl, T.L., Sayler, K.L., Gallant, A.L., Zelenak, D., Reker, R.R., and Rover, J., (2020). Lessons learned implementing an operational continuous United States national land change monitoring capability: The Land Change Monitoring, Assessment, and Projection (LCMAP) approach. Remote Sensing of Environment. https://doi.org/10.1016/j.rse.2019.111356
Zhu, Z., Woodcock, C.E. (2014). Continuous change detection and classification of land cover using all available Landsat data: Remote Sensing of Environment 144: 152–171. https://doi.org/10.1016/j.rse.2014.01.011.