Fraire Week 2

Chapter 1

It’s kind of crazy how fast GIS is growing and how useful it is to know how to use it.

GIS analysis is a process for looking at geographic patterns in your data and at relationships between features.

I honestly struggle sometimes to come up with a research question when using GIS. It’s just such a large storage of data and the endless possibilities are daunting sometimes. It’s also really rewarding to look at your results at the end. Seeing your hard work mapped out and displaying data is super cool.

discrete: It is either there or it’s not, it can be pinpointed. continuous: Like rain/temperature they can be found/measured anywhere. areas enclosed by boundaries. summarized: represents counts or densities of individual features within a boundary (number of businesses in an area, total length of streams of watersheds)

When it started talking about summing certain data for an area I had setnull calculator flashbacks.  I’ve done vectors/rasters in Remote Sensing and I still don’t fully get it. Looking at the pictures it seems like vector is more cookie-cutter in its separation while raster looks gradual.  Figuring out how to overlay layers onto a pre-existing map with a coordinate system almost made me throw the computers last year. Brazil kept ending up in the middle of the ocean instead of overlaying on where it’s supposed to be.

Categories are groups of similar things.  can be represented using numeric codes or text. Ranks put features in order, from high to low. used when direct measures are difficult or if the quantity represents a combination of factors. Counts and amounts show you the total numbers. A count is the actual number of features on a map. An amount can be any measurable quantity associated with a feature.

Counts, amounts, and ratios are continuous values. Categories and ranks are not continuous values.

Chapter 2

This chapter so far reminds me a lot of the Importance of Maps course I took with Krygier. I think he said it’s not a class anymore? but it was based on a lot of map history and the bare structure/make-up of maps.

I also remember that assigning category values is annoying sometimes. The values just just from what you make them and the rules of how it works are really finicky (something for me to remember when doing this work).

why are all of these maps about crimes

At first, I didn’t think that 7 categories was a good max until it showed the map example with more than 7 and it felt very jumbled. This is something I will definitely keep in mind.

I didn’t have a ton of comments for this chapter, it felt very similar to what we learned in Maps so it was mostly a review. It talked about map projections and considerations when displaying maps. It went over the details of maps such as symbols, color, and width that can alter how a viewer perceives the map. I did mention above the few things I learned, but this chapter was also a lot more maps than Chapter 1. I do enjoy looking at them but it makes it harder to take notes sometimes.

Chapter 3

They mentioned the use of graduated colors or line width to show most to least values but this has always been a harder concept for me when making maps. I have a harder time differentiating symbols when they are just gradual transitions of themselves.

I think I have done ratios in ArcGIS and not realized. After reading this chapter I understand what I was doing a bit better now.

Counts and amounts show you the total numbers. Ratios show you the relationship between two quantities and are created by dividing one quantity by another, for each feature. Ranks put features in order, from high to low. Counts, amounts, and ratios are classes. Ranks are individual values.

Creating classes is also frustrating sometimes with Arc Pro. If data is unevenly distributed with gaps: natural breaks. If data is evenly disturbed and I want to emphasize the difference between values: SD or equal interval. If data is evenly distributed and you want to emphasize the relative difference of values: quantile.

I have never used a lot of these features in Arc. Some of them are really cool.