Chapter 1
With GIS it is so fascinating that you are able to predict and prepare for future outcomes using any model you create. Mapping has come a long way, from inaccurate drawings when people would sail around and map the area, all the way to being able to create new maps and find patterns within these maps to more easily understand your surroundings. I like how simple and straightforward it is performing this analysis, just find the data and choose a method then see your results. It seems pretty straightforward with set rules you follow. The different types of features are simple to understand with clear directions of what they are and what they look like. The chapter explained how you can have different types of maps, like vector or raster, they can have harsh lines showing the barriers of different layers, but also soft layers blending them together. Although this can cause information to be lost because of the change in cell size and can affect results of the analysis. It’s important to have all the data layers in the same map projection and coordinate system to make sure you have accurate results. I wonder if there is a way to change the distortion you would get when mapping a larger area, if you can calculate for the curvature of the earth. The categories are good, there isn’t one word for everything but groups of words that mean the same thing and can help describe specific things to break it down or generalize it to see the bigger picture. There are also ranks, which put things in order from high to low. Counts and amounts show the actual number of features on the map, it lets you see the value to compare it to other features. Finally, ratios show the relationship between two quantities divided by one quantity, the map will be able to more accurately show the distribution of features.
Chapter 2
In Chapter 2 we learn to map where things are, we decide what to map, and analyze geographic patterns. We were able to find what we’re looking for and where to take action. I can use a map to identify individual features or look for patterns in the distribution of the features, the maps are able to identify and help find patterns in any information you input into it. Mapping where things are can help one see a visual concentration of the data they are using and solve their problem, or find out if it was just random occurrences and then you would need either more information or change the method you are using. It is important for the map to be appropriate for the audience you are showing it to, if it is for someone who is just learning about this it should be short and not clouded with information that isn’t necessary to them. If it is someone who needs to know a lot of information in one spot it should be well organized with a good system to identify what they are looking for. The chapter talks about making sure to have geographic coordinates input and assign them to your data, you can put it into the GIS database, or it might already exist in another program or in the database. Basic maps can use the same symbol, this can help someone notice patterns easily and solve their problem or question. GIS can draw symbols to identify places or draw linear features that describe streets, rivers or sidewalks, it can also fill plots of land with color or patterns. When you map an area that is large in comparison to the size of the features, it’s best to not use more than 7 categories because it will make the patterns difficult to see, if there are less categories it will make the patterns clearer. The chapter states how it is important to use statistics to measure and find the relationships between your features.
Chapter 3
In chapter three, we learn about comparing places based on quantities so we can see which places meet our criteria. We learned what we need to map, understanding quantities, making a map, and looking for patterns. When we map based on quantities and add a level of information past mapping the locations and features, we will be able to see patterns much clearer and realize what we need to do. Learning how to map features it is important to know what they are called. Discrete features can be individual locations, linear features, or areas. Continuous phenomena can be defined areas or surface continuous values, like areas displayed using graduated colors. Data summarized by area is displayed by shading each area based on its value or using charts to show the amount of each category in each area. In this chapter they talk about the importance of making sure your map is intended for the audience in mind and how the information on your map should represent that. Changing the way the question is framed and how you present your data will help reveal specific patterns. It is also important to understand quantities, the amounts ratios or ranks on your map. Counts and amounts will show the total numbers. Ratios show the relationship between two quantities, and are created by dividing one quantity by another. The most common ratios are averages, proportions, and densities. Averages help compare places that have few features and many features, you can create an average by dividing quantities that use different measures. Proportions show what part of a whole each quantity represents, to create a proportion you divide quantities that use the same measure. It’s important to note that proportions are often presented as percentages. Finally, densities show where features are concentrated, to calculate a density you divide a value by the area of the feature to get a value per unit of area. You can create ratios by adding a new field to the layers data table and calculating new values by dividing two fields containing the counts or amounts.