Mazabras-Week 2

The first chapter in the Textbook was a serious overview of the breakdown of how GIS runs and can be run. They go through all of the different maps to create while in ARC and how they can show your information in that one map or image. They state that there are two ways to represent geographic features one being in vectors and the other rasters. I have worked with rasters before in classes using ARC desktop but I do not think that I have ever used Vectors. The book states that raster models are one easier to manipulate and two people have a wider range of use for rasters. Vectors are a set of coordinates or data that is plugged into the image to connect lines or show large number changes. Another difference between Raster and Vector models is that rasters are made up of pixels that are taken from a camera lens while vectors get all of their information from a table in the GIS software. So throughout this chapter it really shows and tells us what GIS can actually do and how it does it. I know that there are more aspects to ARC because I have done a map that was not mentioned in the first chapter. Although they didn’t mention it in the first chapter I know that Hillshades will show up later in the textbook but this first chapter was really more of how each aspect works and what it can show. Towards the end of the chapter they move into Data tables and how they can be used to show specific data. Some of the data that they show in the book are things like population change, income throughout an area, land use, people per household, ect. There are many different things arc can achieve using data tables because you are able to link these tables with specific areas in your map so the changing data does not move from where the data has come from. 

I would say the focus of the second chapter was to give purpose to the maps that you create and the reason that they were made. It gives just a few examples of the maps that can be created through GIS. They explain the different features that can be linked to the data you are trying to portray, one of them being coordinate pairing. By pairing coordinates the map becomes more precise so you are able to show your data in a more exact way. The book is really looking for the reason the map is being made and how it can help the people or show the people what is happening in that specific area. They also state that by creating separate maps you are able to show a wide range of information because some of the data may correlate with other sets of data. The book uses the example of residential vs commercial areas; they then were able to show assaults, burglaries, thefts and auto thefts in both areas by only using two maps. This is a great example because it gives just a glimpse of how much information can be put into one map or even 2. Another part of the chapter that was mentioned was scale and how it affects the data and the validation of the data. An example they used was how they categorize different features of land. If you are looking at 100 square miles the categories are going to be rough areas whereas if you are looking at a 25 square mile area it would be more precise instead of just showing the general areas. 

In chapter three the three main things that I took away from the chapter were the classes, map creation, and looking for patterns in maps. All three of these features are needed to create a map that shows specific data. In map creation you need to first find out what you are going to portray in the map, then the why factor which is for what reason you are creating the map. This would mean what information and audience that you would want to attract. As you are gathering information for the map you are then able to see patterns throughout the area you are studying. This would mean something like income, as they used in the book to show that there is a very clear drop off in income while you exit the heart of income but towards the outskirts the change is very slow. In the chapter it says you are able to see where there is rapid or gradual change in the information portrayed. The last and biggest part of this chapter would have to be the classes because I believe it has the most effect on maps that include data and information. Classes allow you to see patterns in the map so when you take the accurate data that has been gathered you are able to generalize values and show the gradual or rapid change in values across the map. Patterns and classes can be seen in many different ways because it all depends on how precise the classes are and what type of classification you use. There are classifications for all different sets of data in order to portray them correctly on the map. By having classifications you are able to create a much stronger and accurate map because you are using reliable data with thought out classifications. 

Chapter 4 was a great one to follow three because it gave me the why for mapping with classes. The chapter says the classes can be used to show density if there is a color shade to them with higher values on one end. The second way the chapter says you can map density is by using a dot map or just dots. So instead of using color to show the information on the map you would use a cluster of dots to show the values. Each dot would represent a certain number in your data and then dots are placed accordingly to match with the data. I think this would be a little rough on the eyes but it is an easy way to show simple data to people and get the point across without any questions. Later on in the chapter they go on to use graduated colors to show density in the maps that they create. So instead of using dots to show numbers they are linking colors with certain numbers in the data to show a fading effect on the map. They use the color read and I believe that this is much easier to read and understand rather than trying to count the amount of dots in a certain area. I believe Graduated Colors are the better option when it comes to showing information for density on a map because people would be able to read it easier and other features would be able to be shown on the map like landmarks or roads. By being able to show roads and landmarks people can see where the map is located and really be able to relate to the map and stay interested because they have seen the area before.