pyModis library is a Python library to work with MODIS sensor satellite data. It was originally developed as an interface to download MODIS data from the NASA FTP server but it has grown into a powerful library which also offers further operations on the data.
pyModis has several features:
• it supports downloading of large numbers of original MODIS HDF/XML files. This is ideal for the automated continuous updating of a local archive through a cron job;
• it can parse the XML file to obtain metadata information about the related HDF files; • it can convert a HDF MODIS file to GEOTIFF format;
• it can create a mosaic of several MODIS tiles to obtain large coverages including the creation of the merged XML metadata file with information of all tiles used in this mosaic. For format conversion and mosaicing the MODIS Reprojection Tool (MRT) is required, because at time MRT is the best free and open source software to manage original MODIS data and convert them into a different projection system or format while taking care of the special features of the original Sinusoidal projection.
pyModis is composed of three modules:
• downmodis.py contains a class downModis used to download MODIS data, it requires a “password” for the FTP transfer (usually your email address) and a path where to store the downloaded data. Other parameters are optional, such as the date range or the MODIS product to be downloaded;
• parsemodis.py contains two classes, parseModis that parses metadata of a HDF file returning all useful information. It has also the capability to create a configuration file for MRT; the other class is parseModisMulti, it reads metadata of several HDF files, hence it is used to create the XML file for a mosaic. This class is also able to return the bounding box of all the tiles;
• convertmodis.py is the module to do some simple operations on the original HDF files such as reprojection. It contains three classes and all of them require the MRT software to be installed. convertModis converts HDF files to GeoTIFF format; createMosaic creates a mosaic from several MODIS HDF files into a single HDF file; and processMosaic converts the raw data of MODIS using swath2grid from MRT-Swath.
In pyModis the user can also find five command line tools to easily work with pyModis library. modis_download.py is the tool to download data, modis_parse.py reads metadata of a HDF file, prints information or writes them to a file, modis_multiparse.py reads metadata of several HDF files and prints bounding box or writes the MODIS XML metadata for a mosaic, modis_mosaic.py creates a HDF mosaic from several HDF files, modis_convert.py converts MODIS data to GeoTIFF or other formats and as well as different projection reference systems.
During the presentation all these topics will be discussed and illustrated along with more information about the future of pyModis and the tools for the community (how to contribute or how to report a bug or an enhancement).
