series view
time series visualization environment for land use and land cover change analyses
  1. MODIS data:
    Each graph of the time-series represents the variation over time of the vegetation index (EVI2) for a user? selected pixel on the virtual globe of Google Maps. The EVI2 (Jiang et al., 2008) is based on MODIS images from the MOD13, Q1 product (collection 5, 16 days composite, and spatial resolution of 250 m) available at NASA. The time-series in the blue graph are from the EVI2 values that were pre-filtered using the view zenith angle band, the blue band (surface reflectance), and the date of image acquisition. The time-series in the red graph are from the EVI2 values that were further filtered using wavelet transformation. The 0 flag values in the orange lines shows the gap regions in the time-series. These regions correspond the linear interpolated data which the distance to the nearest valid pixel is greater than 32 days. The gaps regions are characterized by the presence of cloud-contaminated data or other noise type. More details about the filtering method can be obtained in Freitas et al., 2011.
  2. Precipitation data:
    The cumulative monthly rainfall series (millimeters per month) were constructed based on product 3B43 V6 of TRMM (Tropical Rainfall Measuring Mission) available at NASA's Goddard Earth Science (GES) Data and Information Services Center (DISC) Distributed Active Archive Center (DAAC). The same time-series can also be visualized at TRMM Online Visualization and Analysis System. The TRMM pixel has a minimum area of approximately 0.25 degrees (approximately 27.7 km2). The graph of the cumulative monthly rainfall is the TRMM pixel that corresponds to the nearest geographic coordinate of the pixel represented by yellow polygon around the marker.
  3. Projection:
    The MODIS images were reprojected to the sinusoidal projection (WGS84 datum) using the MRT (MODIS Reprojection Tools) software. The graphs of the time-series represent the closest MODIS pixel to the depicted red balloon in the virtual globe of Google Maps. The MODIS pixel is from an area that corresponds to at least 250x250 meters (more details about the MODIS sensor can be found in Wolfe et al., 1998; Wolfe et al., 2002 and Rudorff et al., 2007). Issues related to spectral mixture, borders and its relationship to the scale in which the pixel is visualized should be considered. Furthermore, there is no information with regard to the positioning accuracy and the acquisition date of the images available in the virtual globe of Google Maps. However, the images available at the virtual globe of Google Maps are very helpful to contextualize and better understand the time-series.
  4. Altimetry:
    In addition to the time-series graphs a tool was built to assess the elevation anisotropy around the selected pixel of the virtual globe of Google Maps (red balloon). This tool uses the elevation model information available in the Google Maps API application programming interface The anisotropy visualization is a simple polar plot of elevation around two sample circles, allowing a rapid view of the topography around the selected pixel. This tool allows interactivity and provides a range of distance between the center of the selected coordinate and the sampled circles.
  5. Policies for citations and acknowledgments:
    1. The use of the TRMM data should follow the guidelines presented in the TRMM website. The TRMM (3B43V6) data used in this study are from
      http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?project=TRMM&tree=project.
    2. The use of the MODIS data should follow the guidelines presented in the MODIS website. MODIS data are distributed by the Land Processes Distributed Active Archive Center (LP DAAC), located at U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center (lpdaac.usgs.gov).
    3. The goal of the present portal is to facilitate the public access to the free available time-series of the MODIS and TRMM data for visualizing land use and land cover change. Its use is allowed and encouraged for studies and scientific analyses, and public policies, as long as the data source is mentioned. Publication of images or data used from this portal should be referenced using the following citation: Freitas, R. M.; Arai, E.; Adami, M.; Souza, A. F.; Sato, F. Y.; Shimabukuro, Y. E.; Rosa, R. R.; Anderson, L. O.; Rudorff, B. F. T. Virtual laboratory of remote sensing time series: visualization of MODIS EVI2 data set over South America. Journal of Computational Interdisciplinary Sciences, v 2 (1):57-68. 2011. no prelo. (http://epacis.org/jcis.php).
    4. Whenever possible, please, send us by e-mail (laf@dsr.inpe.br) a copy or reference of your work or oral presentation in which the data available at this portal were used. The reference send to us will be posted in the portal allowing to disclose your work and informing the way data of this portal are being used.
  6. Terms of use:
    Using our services you agree to the following terms:
    1. to accept and follow the policies of using Google products (Terms and Conditions), as maps and markers are displayed on Google Maps;
    2. to not distribute or share the data made available here - ©  LAF Web - without citing sources or following the appropriate policies of "Terms of Use" of each of the third-party products, such as Google, NASA and ©  LAF Web;
    3. to not claim for any data lost. Data saved to favourites, such as polygons registered, files and layers in Shapefile format created by the user may be lost if any storage device fails. There is no backup system of these data at ©  LAF Web;
    4. we are committed not to disclose any user data including name, email, affiliation, points checked, Shapefile and polygons data generated by the user at ©  LAF Web. However, one shall be warned that there is the possibility online hacker intrusions to the system;
    5. LAF team and ©  LAF Web have no obligation to keep this service operating nor continuously;
    6. LAF team and ©  LAF Web have no responsibilities on products, reports, articles etc. generated by the user;
    7. all information generated by the user based on the data extracted by the LAF team and ©  LAF Web does not represent the LAF team and ©  LAF Web views, opinion, formal collaboration or contribution.
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