Science Center Objects

Below you'll find answers to common questions about USGS Land Change Monitoring, Assessment, and Projection (LCMAP).

General LCMAP Questions

Collections

LCMAP Data Products

Data Access

References

 

General LCMAP Questions

What is LCMAP?

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.

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What is time series modeling?

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.

Learn more:

What are LCMAP Collections?

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 Collection 1.1, shifting the provisional year from 2017 (in 1.0) to 2019 (in 1.1).  

 To learn more visit: LCMAP Conterminous United States Data 

 

When will LCMAP data be available for Hawaii and Alaska?

LCMAP data for Hawaii is anticipated to be released in early 2022. 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. 

Collections

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 Conterminous United States Data

Should I still use previously released Collection data after a new Collection is released?

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.

To learn more visit: LCMAP Conterminous United States Data

Where can I find information about the differences between LCMAP Collections?

Visit LCMAP Conterminous United States Data Collection 1.0 vs. Collection 1.1

Where can I find which Collection of Landsat ARD data was used with which LCMAP Collection?

LCMAP Collections do not necessarily correspond to Landsat ARD collections. 

Please visit LCMAP Conterminous United States 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

 

LCMAP Data Products

What LCMAP products are available?

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 1.1 Science Products

LCMAP Reference Data

LCMAP Validation Data

What method is used for creating LCMAP Science Products?

LCMAP uses the Continuous Change Detection and Classification (CCDC) algorithm to create its science products.

To learn more about the LCMAP implementation of the CCDC Algorithm see the LCMAP Collection 1.1 CCDC ADD.

What is the difference between the Primary and Secondary Land Cover products?

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.

To learn more visit: LCMAP Science Product Guide

Watch the video: Primary & Secondary Land Cover

How do I identify model breaks and what they mean?

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 1) or the following year (change after July 1). 

Watch the videoTime of Spectral Change & Spectral Change Magnitude 

Where do I find information about validation and standard errors?

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.

When will the most recently completed collection be made available?

New collections will be released as data and processing allows. CONUS Collection 1.2 (1985-2020) is anticipated to be released in Fall 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.

Data Access

How do I search and download LCMAP data?

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.

Are there any restrictions on the use or redistribution of LCMAP products?

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 V1.1: https://doi.org/10.5066/P9O8TJWG)

Visit the LCMAP Data and Tools page for details about each product.

References

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.