The very concept of free public domain data is frowned upon by the industry and those impacted by the 'free' nature. The most common remarks made against free data include - '...no free lunch..' '...out of date...' and of course the most potent one is '...not of industry standard...'. Academia and researchers who use such data are at times looked down upon.

The year was 1994. I was searching for a quick and easy way of generating DEMs for my doctoral work. Due to the paucity of good Samaritans, I was forced to reverse engineer (digitise paper maps). By the time my work was done, the GTOPO30 data was released. In 2004 the need for realistic terrain data was felt again, this time for a 3D game based watershed development training tool for Indian farmers. We were lucky. The SRTM level 1 data was available. That too for free - though I wished we had level 2 data :-(

Today, the virtual globes make teaching geomorphology and terrain visualisation a breeze. But what if you need the raw elevation data? As of last week, this wish too was granted. NASA, along with Japan's METI, processed ASTER data and generated the global elevation dataset at 1 arc second (30m). And it is free!

The hunger for free data may sound a bit misplaced till one faces the ground realities. A large number of national mapping organisations, even today, have archaic data usage policies. Some have laws preventing digitisation of paper maps. I am told that it is a non-bailable offense in some places. Imagine your predicament in such a place if you are to quantify the soil loss or study landslide hazard or any application which needs slope and elevation data. I just hope the ASTER DEM data stays freely available to the global geospatial community and no super patriotic bureaucrat clamouring about national security nips it.