- GIS Analysis can be defined as looking for geographic patterns in data that is found and is also used at looking at patterns in relationships between features. The process can be described in a few short steps. First, frame the question, understand the data, choose a method for how you will get said data, process the data, and finally look at the results. There’s different types of geographic features and it’s important to understand when dealing with mapping.
- Discrete features- I think they gave an unclear definition for this but I got another definition from Esri. It’s defined as discontinuous but has very defined features.
- Continuous Phenomena- An example of this is precipitation and it can be measured anywhere
- Summarized by area- Represents the density of singular features within a certain boundary or area.
When learning how to map, it’s important to understand the geographic features and their attributes.
- Categories- Groups of things that are alike. Example, categorize roads as highways, alleys, or etc.
- Ranks- Puts things in order specifically from high to low. To put this into context of geographical measures, it may be hard to find a direct measure. An example they gave is assigning soil as all the same suitability for a plant.
- Counts and Amounts are grouped into the same category and are both defined as it shows you total numbers. They are then specifically defined. A count can be defined as the actual number of features on a map. An amount is any measurable quantity that is associated with a feature.
- Ratios- the relationship between two quantities and are created by division. One quantity is divided by another for each feature. It’s like taking an average.
You also have to work with date tables when learning GIS. There’s a lot to GIS. Using data tables you have to learn selecting, calculating, and summarizing.
2. Chapter two is all about mapping. You have to decide what to map, obviously, before you start going crazy. Much like writing a book or article, your focus has to be right and you have to make sure you’re reaching your target audience. The mapping also has to be well organized and relatively easy to follow just like a book, it has to make sense. Kind of off topic but I’ve seen people on TikTok trace a pile of Rice to make a country and they make different features on the map and I thought that was really cool. Anyway, to make a proper map you need to make sure the features you map have geographic coordinates assigned. This means including the latitude and longitude of each mark. To make the map easier to read, you need symbols for different attributes. This makes it easier to see patterns. GIS does the work for you when trying to map something out. Its job is to use the coordinates to draw the attributes or features using the symbol of your choice. You can layer data and then select a specific thing you want to see by itself instead of seeing every feature together. This is very useful when you want to find specific patterns. This can be used in Apple Maps when you’re looking for close attractions but only want to see restaurants. GIS is widely used around the world, but I think not everybody knows the proper name for geographic information systems. When mapping categories, they suggest limiting it to 7. This is because the map could potentially become hard and confusing to look at. The scale matters when mapping these categories because the said features are spread out, then you would be able to map more categories without making it hard to understand.
3. This chapter is called the “Most and Least”. They phrase it as mapping the most and the least places lets us compare things based on the quantity. I thought this was a bit weird at first because I think mapping everything would be the most accurate. Maybe it would be the most accurate but mapping everything makes it harder to understand and could make the map convoluted. This chapter talks about how you have to keep one focus on your map and keep the intended audience in mind. I already stated this in the above chapter and said how making a map is kind of like writing an article. You have to keep the map purpose from drifting off. This chapter seems like a review. Quantities can be counts or amounts and knowing the difference will help you best pick which one to use for a map.
A new idea they introduce is density. When densities show in a map it shows where those features are most concentrated. The chapter starts going into data like statistics. I know this is important to GIS but I hate math. Matter of fact, I took stats during COVID so I actually learned nothing. What I know about stats is that I hate everything about it including standard deviation. The easy thing to understand about stats is that some data may have outliers. This means that there will be points that lie way outside of the average points. This could then skew the data either left or right. There’s different ways to label and create a map including graduate symbols, colors, contours, charts, and 3D viewing. Graduated symbols show a range of values. Charts show categories and quantities. These are for discrete areas. You can use pie charts and bar graphs to show data as well but I think we all know that.