Python Fundamentals

 

Python Environments and Flowcharts

This first assignment in GIS programming was designed to show us the Python environment, how to use it, and how to create flowcharts. Going into this class with no prior experience in programming, I feel much more at ease after completing this week's module. Below is a simple flowchart created to demonstrating the logical process of how the problem (degrees=radians*180/pi) can be solved.

Another requirement for this week was to read “The Zen of Python” by Tim Peters. This is a set of 19 "guiding principles" that can be found by typing import this into IDLE. I believe these guiding principles are a shared philosophy within the Python community to emphasize to the user the importance of simplicity, clarity, and readability when writing code in Python. The purpose is to set a standard that anyone and everyone can understand and use. Python is, after all, for anyone who wants to learn to code and not just for the coding experts. The line “Explicit is better than implicit” resonates with me most, as I value clear and concise instruction that is unambiguous, leaving little space for guessing at any underlining meaning.

 

Supervised Classification

 

Spatial Enhancement, Multispectral Data, and Band Indices

 
This week's lab focused on my neck of the woods in the Pacific Northwest.  It was fun getting to learn about different spectral combinations to identify features in a region that I am very well acquainted with.

The focus this week was to learn how to use different processes to identify features in an image. Some of these processes included the use of histograms, image enhancement methods, and the use of spectral characteristics.

Introduction to ERDAS and Digital Data

This weeks lab had us focusing on using ERDAS Imagine. This was my first time using this software so, this lab was a little slow going at first. Especially since the lab instructions were clearly created using an older version of the software which resulted in a lot of "hunt and peck" on my end. However, once I got used to it, it became more intuitive. 

I appreciated the second half of the lab because it was focused on showing the functionality and utilization of tools in ERDAS. There are quite a few similarities to ArcGIS but overall, ERDAS is a little more user friendly.
 

Land Use Land Cover and Ground Truthing

 

Ariel Photography: Visual Interpretation

The objective for exercise 1 was to identify the tone and texture of an aerial photograph. Tone can be described as the brightness or darkness of an area so, the task was to create polygons around areas in the photograph that could be described as very light, light, medium, dark, and very dark. The next task was to identify areas of varying texture which involved a similar process to that of identifying tone. Texture in this case is defined as how smooth or rough the surface appears to be. For this task, polygons were drawn around areas perceived as either very fine, fine, mottled, coarse, and very coarse.

In these tasks, I did accomplish identifying areas of varying tones and textures. I had some challenges because I had to relearn how to create polygons but once I figured it out, the process went smoothly. My next challenge was labeling the polygons. In my first few attempts, the labels did not appear. I believe the problem was simply that the text was too large for the polygons so after adjusting a few settings, I was able to see the labels. 

 The objective of exercise 2 was to identify areas in an aerial photograph by the shape and size (an easily recognizable object like a tree or building), shadow ( an object that can be recognized by the shadow it casts like a water tower), pattern (an area that is recognizable not by a single object but by multiples of an object such as a farm), and association (areas in which conclusions can be drawn based on surrounding features).

With these tasks, new features had to be created, similar to exercise one, but these features were not drawn polygons and were instead points being made on the photo. This exercise went much smoother for me as I had worked out any difficulties in the process for the first exercise.