Terra-i is a system for near real time land cover or habitat change monitoring using the MODIS sensor on NASA’s Terra and Aqua platforms. We use machine learning algorithms to bring you maps and analyses of habitat change every 16 days from 2004 to present. You can visualise the data within a geobrowser (web map) environment freely or download the Geographical Information Systems (GIS) files for further analysis (after creating a free account).
Terra-i uses data from the Moderate-Resolution Imaging Spectroradiometer (MODIS) sensor which provides images of the entire surface of the globe every 1 to 2 days. This sensor has a high radiometric sensitivity and provides images for 36 bands of the electromagnetic spectrum.
The world is divided into 10 x 10 degree "tiles" or boxes, with a global coverage and a spatial resolution of 250m every 16 days since February 18, 2000 to the current date. For the detection of changes in the habitat, Terra-i uses the MODIS vegetation indices from the product MOD13Q1, and precipitation data from the Tropical Rainfall Measuring Mission (TRMM) sensor.
• MODIS vegetation indices data (view)
The vegetation indices are designed to provide a permanent and consistent comparison of the temporal and spatial changes of vegetation by responding to the amount of photosynthetically active radiation in a given pixel, to the chlorophyll content, to the leaf area and the structural characteristics of plants. [Huete, Justice y Leeuwen 1999]. The Normalized Difference Vegetation Index (NDVI) [Asrar et al., 1984, Sellers et al., 1992] is an indicator of whether a given area contains live green vegetation or not. The reliability of this index has been shown multiples times, by [Asrar et al., 1984, Sellers et al., 1992] for example. NDVI measures the spectral response of the vegetation. If the vegetation is degraded, it will reflect the blue and even more the red (R) visible spectrum. On the other hand, if the vegetation is healthy, it will reflect the near-infrared spectrum (NIR). Following this principle, many studies [Lloyd, 1990, Kaduk and Heimann, 1996, Moulin et al., 1997, White et al., 1997, Salinas-Zavalaa et al., 2002, Zhang et al., 2003] analyze NDVI time series to derive robust phenology markers such as the start and the end of growing seasons for vegetation.
Terra-i uses NDVI data as well as the quality assessment data provided with a 16 days frequency and a 250m spatial resolution by the MOD13Q1 product.
• TRMM precipitation data (view)
The Precipitation Radar (PR) aboard the satellite Tropical Rainfall Measuring Mission (TRMM) is the first weather radar designed to measure the vertical structure of tropospheric precipitation in the tropics and subtropics. [Kozu et al., 2001]. Terra-i uses data from the TRMM precipitation sensor with a measurement frequency of 3 hours and a resolution of 28km.
• Water bodies presence data from MODIS (view)
Terra-i uses the product MOD35 (Cloud Mask) in its final stage of processing to mask the presence of water pixels and thus filter habitat change detections due to flooding and/or increases of water bodies.
Terra-i generates maps of habitat changes every 16 days for each MODIS tile in Latin America from 2004 to the current date.