Image Rectification

Having a map rectified to map coordinates can be beneficial especially if you use the image a background layer for digitizing objects on a map. Currently I use rectified images for this purpose. I also can see the usefulness in geo-intelligence. Anlysists can give map coordinates of objects of concern in an image that may require on ground analysis.

The two main pitfalls I encounter in this lab were, accurate ground control points and an image that is fuzzy, which will lead to inaccurate ground control points. It is important that the image being rectified has enough landmarks to use as ground control points. If the image is of a large body of water it would be difficult to have enough landmarks in order to get a precise rectification of the image.

Module 3 Lab

1. Provide a brief description of why the following features appear as they do in this thermal infrared image: This image was taken of Fort Worth, Tx during the winter and in the morning. The heat island effect can explain why roads, automobiles, sidewalks, and bright spots on many rooftops. Roads absorb more heat and remain warmer through the night as do sidewalks and patios. The bright spots on the rooftops are chimneys; all of these objects add thermal energy to the air. Whereas storage sheds, natural and man-mad vegetation cool off quicker throughout the night and release less thermal energy to the air.

2. Explain why the front parts of the cars have a hot spot on them at arrows number 1 and 2. The engines are running.

Module 2 Lab

The first photo is the Multi-spectral mode (R2, G3, B4) display and the second photo is the Panchromatic display. The contrast between the two photos that if most noticeable, is the appearance of land. It is blue in the first photo, whereas its black in the second photo. Another distinguishable contrast is how water is represented. Water has a reddish tint in the first photo compared to the water is a dark gray color in the second photo. The water in both photo's change color relative to the depth of the water, lighter color represent shallower depths and gets darker as the water depth increases. Urban areas in both photos are have white apperance.