The second week of our GIS Special Topics in Archaeology course continues our experimentation with remotely sensed data from Landsat 7 in our search for Mayan pyramids. In this assignment, however, we focused on the infrared bands in looking at the electromagnetic radiation signature of the region's vegetation in the hope of locating archaeological remains hidden underneath. We first utilized our false color composite from last week to create a normalized difference vegetation index (NDVI), which represents the difference between the red and infrared bands. This is intended to show the plant life as communicated by EMR. The next map we created was a composite consisting of Landsat bands 4,5, and 1. Incorporating two bands of infrared data, this composite represents more detailed information on the health of plant life. The final map is the result of a supervised classification of the 451 composite, created from a training sample focused on locating more remains based on the EMR signature of the La Danta pyramid.
I made several goes at the training sample before I reached one I was reasonably satisfied with. My final classification over-represents bare ground, but it is less egregious than my earlier ones. Not many areas returned positive hits for pyramids which is better than too many hits. I do believe the areas returned as possible archaeological remains would be worth a look, although further data and analysis would always be welcome.
No comments:
Post a Comment