Reverb makes it easy to find and download satellite data

If you need MODIS satellite data, you should check Nasa’s Reverb web portal. It is a, and I quote, “next generation metadata and service discovery tool”. But, as it turns out, is is already available for our generation ;-), just head over to http://reverb.echo.nasa.gov/.

It has indeed a fairly convenient interface in the form of an online map. You just zoom in to the area of interest and than click and drag a bounding rectangle.

Extracting lines ending with specific character using sed or grep

A quick note (to myself mostly) about how to extract lines from a text file that end with a specific set of characters. In Linux, you can very easily do this using ‘grep’ or ‘sed’. But, first a little bit of background.

Opening MODIS tiles in QGIS

NASA offers a very convenient web-based tool to select and download the tiles you need; Reverb / ECHO.  The tiles are in HDF format and use the Sinusoidal grid tiling system (proj4 definition: +proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs). But you probably want to have the data in another data format and in another projection. NASA offers a very convenient cross-platform tool to reproject and convert the data (it also makes it very easy to mosaic tiles): the Modis Reprojection Tool (MRT).

But something I didn’t know is that it is also possible to open the tiles directly in QGIS.