Monday, November 6, 2023

Remote Sensing - Module 3 - Intro to ERDAS Imagine and Digital Data

The third lab for Remote Sensing and Photo Interpretation introduced us to ERDAS Imagine. This included familiarization with the layout of the workspace and the use of some of its basic tools and functions.  We began by learning how to properly add raster layers to the Viewer. We continued with an exercise adding both AVHRR (Advanced Very High Resolution Radiometer) imagery as well as Landsat Thematic Mapper (TM) imagery. This involved comparing the difference in spatial resolution between the two types. Using the Landsat image we changed the band combinations observing the differences between the different combinations such as False Natural Color vs False Color IR. It was very interesting to observe the visibility differences between the two. We concluded part A of the lab by creating a subset image of our original and added an area column in order to calculate the area of thematic classifications represented in our new subset image. We then opened our new subset image in ArcGIS Pro and created a map as seen below.


In part B of the lab we began by learning how to examine layer metadata through the Layer Info feature which contains important information about the image, including number of layers, file, image and pixel size, projection information and statistical information. Next was an exercise focusing on spatial resolution where we compared some images that depicted the same area on the ground but their level of detail varied. Next was a similar exercise about Radiometric Resolution and then we finished with an exercise with Thematic Rasters and Attributes. This involved calculating area and generating a formula statement in order to meet certain criteria.



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