This week we will be concentrating on finishing our tutorials through ArcGIS, which are going very well. We also mapped Delaware data on ArcGIS.
Getting to Know ArcGIS chapter 8,9
February 24, 2008
Chapter 8, 9 dealt with joining and relating tables, which was not something I was looking forward to, because in Geography 353 last Spring I definitely got frustrated d attempting to do this. The tutorial helped my understanding a bit, but I still don’t grasp the difference between the two. I do feel a little bit more comfortable than I did before. Hopefully as we move along in the book I work on understand this better.
Today in class each group discussed our findings while driving around Delaware County taking pictures. It was neat seeing different parts of the county that I have not experience in my 5 years out in Delaware, Ohio.
Western Delaware County - a bunch of my groups pictures
Delaware Expedition
February 19, 2008
Today my group drove around Delaware, OH and took some pictures of things we saw. It was a good time seeing places around Delaware I did not know about.
Getting to Know ArcGIS chapter 1 and 2
February 18, 2008
Chapter one of the ArcGIS book is a refreshing review of a lot of things we have learned in class so far this semester in Mitchell’s book and class lectures. A lot of the material on data and features are all similar to what we did in Geography 353, which I completed last spring. Chapter 2 shifts a little more a first to the types of GIS programs that are available to purchase and what the differences are between the applications, and what they do. It was interesting to learn about the different applications .
Today my group presented chapters 3,6, and 7 from Mitchell’s book. We also presented on environmental justice and our sources pretaining to it.
I presented chapter 7 from GIS Anaylsis. I have an in depth discussion about the book in my reading discussions tab.
Chapter 7: Mapping Change
GIS lets you map where things move or the changing conditions in a place over time. (149)
Why Map Change?
- People map what’s changed to anticipate future conditions, to decide a course of action, or even to evaluate the results of a certain policy or action.
- You can gain insight to things by mapping how they behave
- a meteorologist studying the path of hurricanes to predict where and when a future one can occur.
- Wildlife biologist studying the movement of bears over a 24- hour period
- Anticipating future change is another reason to map.
- A police chief studying how crime patterns from month to month, or year to year to assign officers to specific places.
- Transportation planner looking at trends in traffic flow to see where lanes need to be added in the future.
- You can see the impact of conditions by mapping them before they happen.
- Map Gallery: Maps are being created by biologists in Orlando, Florida at the St. Johns River Water Management district to map change from 1941-1987. These maps allowed the biologist to compare and understand how the historical vegetation patterns have changed and how the current conditions have developed. This information that is formed in these maps allows the district to restore the wetlands to create more waterfowl habitat, provides more recreation, and even includes water quality.
Defining Your Analysis
- You can map change by showing the location and conditions of features of each date. You can also map the difference in a value between two and more dates.
- Knowing the type of change and type of features you are working with, it will help you decide how to map the change
· The types of change come in 2 forms:
- Change in location- allows you to show how features behave so you can predict how they move.
– Change in character or magnitude- shows how conditions in a given place have changed.
- Discrete features: you can map features that physically move, even as they move through space. They can be individual features such as a hurricane, vehicle, or an animal.- Measuring time: Time will affect the geographic patterns you see on your map
- There are 3 types of time patterns:
1. A trend: change between two or more dates at a time. Trends indicate whether something is increasing or decreasing.
2. Before and after: conditions of something before an event, and after the event
3. A cycle: change over a period time; day, month, year.
- Snapshots show the condition at any given moment- it is used to map the phenomena.
- Summarizing is used for mapping DISCRETE events in an actual place that are not continuous in time.
- 911 calls made in a given month.
- Mapping trends needs you to determine the interval, the number of dates and the duration. The duration DIVIDED by the number of dates yields the interval ( 155).
- The interval does not necessarily need to be determined if there only has been a few dates collected—but you if you have a range of dates, you can chose the interval.
- The number of dates you use depend on the consistency of the change you are mapping. You have to really look at the date to determine what interval is best, because if you have fewer dates with a wider interval you may miss some changes.
- When mapping cycles , you can show the change in a snapshot or summarize over a period, depending on your data. ( discrete or continuous).
- For discrete you summarize the events.
Creating a Time Series
Creating a set of time series map is very similar to making maps to show where features are or where the most and least are.
- A time series is effective for showing the patterns movement if you are tracking many individual features. You want to include some stationary features, too.
- Time series maps are very good at showing the change in magnitude for DISCRETE areas and surfaces, especially in a large change.
- Displaying tables and charts around your map also helps show change. Also, you can combine tables by using the category field to join them and create charts.
Creating a Tracking Map
- A tracking map shows the position of a feature or features at several dates and times. It is useful for showing incremental movement of discrete features.
- Mapping the movement of linear features is extremely helpful too. To do that you draw them using different colors for each date or time, and label each.
- Linear features are more often mapped for a before and after event.
- To map the movement of a contiguous feature, you draw the boundaries of the area at each time or date. Using different colors, you alternately shade the areas to distinguish different patterns. You can be creative with how you want to shade them.
Measuring and Mapping Change
- To measure and map change you calculate the difference in the values between the two dates and map the features. With discrete features- the values you are mapping are stored in the layers data table.
- Calculating change as a percent lets you compare the relative rather than the absolute.
- For individual locations- use colors or symbols to represent the calculated value
- Like a store mapping the stores by percentage in sales year by year- you could map the trend using a trend line.
- Use graduated symbols for areas such as parcels
- Calculating change for data summarized by data- it is the same as calculating discrete features. Once you calculate the change, you make the maps based on the value. Use graduated colors to show the change.
- You can create charts and trend line charts to show the changes of different periods.
- Some features may have negative values. When making the maps, set data values that are negative, and set that as one color ( like a blue)
- By using vector and raster data you can create a map of areas that have changed
.- When using vector data, you overlay the areas to create a new layer containing category codes for both dates.
- Raster data, you create a new layer of the two inputs.- When you have continuous numeric values for two date, you want to calculate change.
- TO create a change map between the two surfaces you subtract the layers. The map shows where the most and least have changed.
Today, some of my classmates discussed chapter 2,4,5 of Andy Mitchell’s Guide to GIS Analysis. We also disussed our project a bit and checked in with what we needed to have blogged for the upcoming week.
Environmental Justice
February 2, 2008
What is Environmental Justice?
ü The fear treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect of the development, implementation, and enforcement of environmental laws, regulations and policies.
ü EPA has a goal- it will be achieved when everyone enjoys the same degree of protection from environmental health hazards and equal access to the decision making process to have a healthy environment.
Environmental Justice- Souce 1.
3 Fundamental environmental Justice Principles:
1. Avoid, minimize, mitigate disproportionately high and adverse human health and environmental effects including social/economic effects on minority populations and low income populations.
2. To ensure the full and fair participants by all potentially affected communities in the transition decision-making process.
3. To prevent the denial of, reduction in, or significant delay in the receipt of benefits by minority and low-income populations.
Environmental Justice- source 2
ENVIRONMENTAL BURDENS
ü An important, sensitive, and hard to measure subject. Advocates makes a strong case that poor communities and communities of color can bear more than their share of environmental burdens.
Andy Mitchell- ESRI ® Guide to GIS Analysis chapter 4-6
February 1, 2008
Chapter 4- Mapping density
Mapping the density of features lets you see the patterns of where things are concentrate. This allows you to find areas that require action or mointore changing condisitons. Density maps are useful in looking at patterns rather than looking at locations of individual features or mapping by size. Census tracts or counties are espesially useful as density maps. There are a few ways to map density, as this chapter describes. One way is to shade definded areas based on density value. Before you actually do your mapping, it is important to think about the features you are mapping. This chapter describes in a clear, interesting way to map density. From the way they explained this, it seems like something that is relatively easy to compose in GIS. Chapter 5: Finding what’s Inside
Finding what’s actually inside lets you see whether an activity occurs inside an area , or summarize information for each of several areas so you can compare them. This chapter goes into depth on different ways to go inside a single area or a few areas, and determine whether extra attention needs to be taken or not. Mitchell describes 3 ways of ‘finding what is inside’. The first is Drawing the areas and features, in which you create a map showing the boundary of the area and the features. Second, Selecting teh Features inside the area, you specify the area and the layer containing the features, and the GIS selects a subset of the features inside the area. Lastly, overlaying the areas and features, which GIS combines the area and the feautures to create a new layer with the attributes of both, or compares the two layers to calculate summary statistics for each area on the fly. They each have interesting merits.Chapter 6: Finding What is nearbyFinding what is near by lets you see what is within a set of distance or travel range of a feature. This lets you monitor events in an area, or find the area served by a facility or the features of affected by an activity. This chapter describes methods such as straight-line distance, distance or cost over a network, and distance across a surface. These applications seem to be very important in determining how far away thingd are. This is a great chapter in allowing the readers to understand the different methods as well as a lot of very helpful features.
