Skills Acquired:

• Gained familiarity with geographic properties of GIS data (coordinate systems, datums, etc.)
• Aligned spatial data via proper spatial referencing
• Evaluated inherent potential pitfalls in interpretation owing from raster resolution and the mixed pixel problem (MPP)
• Analyzed and manipulated remote sensing images

Fixing Misaligned and improperly referenced spatial data

When there are thousands of map projections out there preserving every combination of area, shape, angle, distance, and direction you can conceive of, it’s little wonder that spatial data can end up hopelessly mangled – misaligned, out of place, and of ill fitness for even qualitative, much less quantitative, analysis.

To fix layers with disparate map projections and coordinate systems, one should use ArcCatalog to check layer properties, changing the XY Coordinates to a common framework over all layers of interest. As for the matter of projection, ArcMap has the cool and convenient feature of ‘projecting-on-the-fly’, in which data are automatically projected to a standard, or manual, user-implemented projection using the ‘Projections and Transformations’ tool in ArcToolbox. These two steps in conjunction should allow for the display of all layers atop one another, opening the door for spatial correlation, statistical analysis, and the provision of answers to your research questions.

Advantages of Remote Sensing: Landsat data for geographic analysis

Why use Landsat data? Taken every days, with comprehensive, multi-spectral remotely-sensed data encompassing the entirety of the Earth’s surface, Landsat data is an invaluable resource for the long-term monitoring of environmental data, as well as for analysis of changes to systems owing from short-term, spontaneous processes. Take for instance the 2004 Indian Ocean Tsunami that struck on Boxing Day, devastated South Asian populations, and provoked a massive humanitarian relief effort. The region of Aceh, Indonesia was once of the first to be struck, its coastline dropping up to 1m and nearby islands uplifted by up to 2m. Such an inundation provoked manifold geomorphological changes, including drowned river valleys. Owing from the destruction of local coral reefs, there also exists the prospect for long term coastal retreat. And what better way to track these changes, from before the tsunami to the months and years afterwards, than with spatially resolved, temporally separated data? The future of agriculture, infrastructure, and ecology are all on the line in this region – and a precarious one at that. Fortunately, Landsat can lend a hand.