Chapter 1: GIS itself is the process of looking at geographical patterns in your data and at the relationship between the features within said data.
Start by framing your question: This can typically start off as a question, and being as specific as possible about the question you are asking will help with deciding the best method to approach it with. Understanding your data can also aid in making things more clear and narrowing down what method you should use. Finish by looking at your results and deciding if the data is relevant/useful, or if you should use a different approach.
There are multiple kinds of features in GIS: For discrete locations and lines, the actual location can be pinpointed, and the feature is either present or not. Continuous phenomena like precipitation can be found or measured anywhere. Summarized data represent the counts or density of individual features within area boundaries.
Vector and Raster: With the vector model, each feature is a row in a table, and feature shapes are defined by x, and y locations in space. With the raster model, features are represented as a matrix of cells in continuous space.
Types of attribute styles: Categories, ranks, counts, amounts, ratios
The only thing I worry about from this chapter is coming up with my own question. There are so many different topics with so many different subtopics, and the possibilities are so open that it’s almost overwhelming.
Chapter 2: Prepping your data involves ensuring that the features you are mapping have geographic coordinates assigned and have a category attribute with a value for each feature. If you are bringing data from another program or entering it by hand, the features will need to have location information like a street address or latitude-longitude, and GIS will assign the coordinates.
To make your own map, you’ll tell GIS which features you want to display and what symbols to use to draw them. Mapping a single type involves drawing all features with the same symbol, while mapping by category involves using a different symbol for each category. If you use the method with multiple categories, you shouldn’t use more than seven categories, otherwise, you will have to group categories.
Along with symbols, text labels can also be used to help distinguish categories (e.g. OW = Open water)
Chapter 3: This chapter continues to discuss different methods of displaying data, as well as how they should be understood. It seems like the best method for display varies between the project and what its purpose is.
Natural breaks: Data is not evenly distributed
Quartile: Data is evenly distributed
Proportion: part of the whole
Rank: high, medium, low
Density: concentration of data/feature
I found all three chapters helpful in terms of explaining the basics of GIS. There are pictures to illustrate every point that is made, which is super helpful for me, as I have always needed some kind of visual or example to understand any concept.
All good. Just try to hold all this in your head as we move through the concepts. You will see how they play out in examples when you get into the software. It’s a lot but will start to coalesce in your mind as we move through it all.