The three largest countries in North America share trade, climate and culture in a host of broad and specific ways. A new set of land cover maps for the U.S., Canada, and Mexico highlights a specific, long-standing scientific collaboration designed to benefit each nation.
The North American Land Change Monitoring System (NALCMS), led by the U.S. Geological Survey (USGS) in the U.S., offers important insight on land change across the continent and a starting point for a wide range of scientific inquiry.
Newly released NALCMS data depicts 19 classes of land cover across North America for the year 2015 at 30-meter spatial resolution. The freely-available maps were built using a variety of satellite data sources, with U.S. and Canadian maps leaning heavily on data from the USGS Landsat series of satellites, operated by the USGS Earth Resources Observation and Science (EROS) Center near Sioux Falls, SD.
The 2015 publication is the highest-quality land cover product for North America to date and boasts improved accuracy in land cover classification from the previous 2010 product. NALCMS data also offer land cover products for 2005, and will soon update its land change maps to include a 2010 to 2015 change comparison.
The maps serve as an international extension of the work done by the National Land Cover Database (NLCD) in the U.S., according to Collin Homer, the NCLD program manager and NALCMS lead for the USGS. The U.S. mapping data is modified for NALCMS to include land cover classes with specific relevance to the project’s continental partners, such as temperate or subpolar forests for Canada’s far north or tropical or subtropical forests for Mexico.
Aligning the U.S. data, which was updated and upgraded with the 2019 release of NLCD 2016, involved the incorporation of factors such as temperature and permafrost.
“NLCD is the foundation, but this is 19 land cover classes, several of which are different from NLCD,” Homer said. “So we actually had to harmonize our works with some of these other ancillary datasets.”
The resulting harmonized, 3-nation dataset offers invaluable support to international organizations, nongovernmental conservation organizations, land managers, scientific researchers and others, by allowing them to better understand the dynamics and continental-scale patterns of North America’s land cover and to conduct both regional and local-level analyses.
Studies using NALCMS include:
- An air quality monitoring system in Canada, which factored land cover data into its twice-daily air quality reporting during the Canadian fire season,
- An assessment of species vulnerability to land and climate change for the Great Northern Landscape Conservation Cooperative (an area stretching from British Columbia to Wyoming)
- A study of forest disturbance in Mexico’s Yucatan Peninsula.
All NALCMS datasets are available for download at no cost to the user through the project’s website. The project also maintains an interactive web viewer that includes photographs and descriptions of each land cover class.
About the North American Land Change Monitoring System
NALCMS is a joint initiative between the Canada Centre for Mapping and Earth Observation of Natural Resources Canada (NRCan), the United States Geological Survey (USGS), and three Mexican organizations: the National Institute of Statistics and Geography (Instituto Nacional de Estadística y Geografía—INEGI), the National Commission for the Knowledge and Use of Biodiversity (Comisión Nacional para el Conocimiento y Uso de la Biodiversidad—Conabio), and the National Forestry Commission (Comisión Nacional Forestal—Conafor), and supported by the Commission for Environmental Cooperation (CEC) http://www.cec.org/nalcms.
About the North American Environmental Atlas
NALCMS is part of the CEC’s North American Environmental Atlas, bringing together maps, data and interactive map layers to allow for continental and regional perspectives on environmental issues that cross boundaries.