Geography 291: Geospatial Analysis with Desktop GIS

 

Chaoter 3 I found dashboard and creating map element confusing had trouble with App Launcher.

 

Chapter 7

Chapter 7 introduced me to the process of manually digitizing features using various tools. I became more familiar with using basemaps throughout these lessons and learned how to edit and create vector map features. The tutorials were straightforward, allowing me to quickly grasp how to adjust polygons to align with building outlines by using the move, rotate, and resize tools. To achieve greater precision in aligning the polygons, I utilized the construction toolbar to add refined points, known as vertex points, to the corners of the buildings. Section 7.1 focused on the finer details of GIS work, helping me create polished maps at close range. In section 7.2, I gained valuable insights into symbolizing point features for parking lots and transportation locations on campus. However, the “Your Turn” exercise in section 7.2 posed some challenges, as the instructions did not clearly specify that I needed to change the feature class type to point. Additionally, I had difficulty locating the bus symbol and had to explore the symbology panel further to find the appropriate symbol. The next lesson guided me through editing polygon shapes and smoothing the green spaces. I practiced using the smooth polygon tool in the “Your Turn” section on Panther Hollow Lake. The final skill I learned was how to take a CAD layer and match it to the corresponding feature on the actual map.

Chapter 8

Chapter 8 focuses on geocoding, which is the process of matching addresses from the locator database to tabular data. I learned how to place points using this table data, but I also discovered that even a small mistake can result in inaccurate data points due to mismatches. To address the issues I encountered, I used the calculation tool in the attribute table menu, which provided valuable insights into the data. I practiced applying geocoding processes using zip codes, which helped me visualize how geocoding can effectively illustrate the concentration of a specific feature in a given area.

Chapter 9 

This chapter introduced me to various analytical methods that can be used for multiple purposes. The four methods covered are buffers, service areas, facility location models, and clustering. The buffer tool helps identify features within a specific radius. In lessons 9.1 and 9.2, I applied my knowledge of the pairwise buffer tool using data from 32 pools to estimate the number of children aged 5 to 17 living within a radius of 0.5 to 1.5 miles. Lesson 9.2 focused on teaching me how to use a multiple-ring buffer, which enhances the capabilities of the buffer tool. I learned that the purpose of the multiple-ring buffer is to focus on different features that fall within the specified distances of the buffered feature. Service areas are essential when I am working on a map that focuses on travel data.

Chapter 4: File Geodatabases

• A file geodatabase (.gdb) is Esri’s preferred way to store feature classes and tables, so shapefiles and CSVs get imported into it first.
• A join only works when both key fields are the same data type, which is why the text GEOID has to be turned into a number before joining census data.
• Spatial Join counts points inside polygons, such as burglaries per neighborhood.
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Question: Why does SQL run AND before OR, and how often do missing parentheses give wrong results without anyone noticing?

Chapter 5: Spatial Data

• In raw latitude/longitude, the poles stretch into lines and Greenland and Antarctica look huge. Switching the map to Robinson fixes most of that.
• For the US I used Albers Equal Area Conic, the standard projection for USGS and Census maps, because it keeps areas accurate.
• Local maps use State Plane. Adding the Municipalities layer switched the whole map to PA South, and the lat/long Tracts layer was projected on the fly.
• Turned a table of NYC library X/Y coordinates into points. My first two tries came out empty because no coordinate system was set. Setting State Plane NY Long Island (3104) fixed it.

Question: If layers get projected on the fly anyway, when does it actually matter which coordinate system the data is stored in?

Chapter 6: Geoprocessing

• Pairwise Dissolve merged Manhattan block groups into neighborhoods by name and removed the inner boundaries.
• For the Upper West Side, I exported the neighborhood, used Select By Location on the streets, then clipped them so they stop exactly at the boundary.
• Merge combined five separate borough water layers into one NYC water layer.
  

Question: Clip, Intersect, and Tabulate Intersection all overlay two layers. How do you decide which one fits a question?

Chapter 2 labeling and feature layers were eaier to locate and apply.

 

Chapter one was fun but all the different  panes and options were hard to find without the search tool.

 

Chapter 7

In this chapter, I learned all about the different methods of digitizing. I first was introduced to the process of moving, rotating, splitting, and adding more vertices to polygons on a map. Although this process was simple, I appreciated that it led to a cleaner look and allowed the polygons to stand as a more accurate representation of the locations on the map. The next tutorial focused on adding and deleting a polygon feature class. Although I did not have any problems with the guided tutorial, I struggled with the “your turn” section. After a while of retracing my steps, I eventually figured out that I forgot to change the feature class I was adding to point instead of polygon. This meant that I wasn’t allowed to use the correct symbology or data format. Sometimes I wish in situations like these the chapter would give us links for previous instructions or reminders if we forgot how to do a process. I then learned about the steps of how to smooth polygons. This process further contributed to a more professional looking map. The last tutorial taught me how to use the georeference and transformation tool on polygons. I found this section to be the hardest in this chapter because there were many steps that had to be performed correctly in order for the function to work. For example, I had trouble with the transform polygon feature. When setting the output coordinate system for one of the feature classes, I accidentally changed the wrong one. This meant that I could not link the layers to each other because they did not have corresponding coordinate systems. This mistake emphasized the importance of making sure to follow and pay attention to the little things when working with GIS.

Chapter 8

Chapter 8 focused on the definition and the process of geocoding. Geocoding takes data in the form of text, such as street addresses or zip codes, and plots them as geographic coordinates on a map. Although there are components that are applied in order to make this process as accurate as possible, there are still some problems that come with geocoding. One issue is that there are often misspellings, abbreviations, or omissions of names causing confusion when matching the sources to reference data. GIS combats this by calculating a percent accuracy of each source through the subtraction of points for each problem that occurred. Although there is no way to truly judge if matches are correct, this process is able to review some of the nonmatched sources and incorrect matches to improve the reliability of geocoding for the many organizations that rely on it today. 

The first tutorial introduced me to how to geocode data using zip codes. This included the process of building a zip code locator, establishing geocode addresses, and rematching data. This type of mapping would be extremely useful in seeing where the majority of an organization or event population resides. The second tutorial walked me through a similar process, but this time I geocoded data for street addresses. For me, this chapter was probably the simplest and quickest one so far. Although there were not that many tutorials to work on, the chapter introduced a large amount of necessary background information about geocoding.

Key Concepts/Definitions

Geocoding: GIS process that matches location fields in tabular data to corresponding fields in existing feature classes to map the tabular data.

Chapter 9

This chapter marked the beginning of the last section of the book: applying advanced GIS technologies. It focused on the idea that even when you have the right dataset for a subject, sometimes visualization of spatial data is needed to answer questions and solve problems. The chapter covered four different spatial analysis methods that included buffers, service areas, facility location models, and clustering. Buffers are generally used to find what’s near a feature or to see how many people are located within a specified distance of a feature. The buffer map was my favorite way to visualize data from this chapter. To me, this method provided the most accurate visual representation of the differing spatial data. Service areas are like buffers but instead of distance from a feature, it is based on travel over a network. The facility location model uses Network Analyst to find the best locations for new features such as facilities. This map was interesting to look at because the representation of the data was presented in a way I have not seen before. Lastly, the clustering method focuses on the ability to identify clusters of data points that are closer to each other but distant from other clusters. Although I was able to complete this section, my results were not exactly lining up with the tutorials. I was getting all of the same numbers for frequency and mean, but my cluster ids did not match. As a result, my symbology for the groups also did not match. I do not know if this is a problem that happened on my end or if it was just the fact that ArcGIS Pro is now on a slightly different version than the book I currently use.

Key Concepts/Definitions

Buffer: A polygon surrounding map features of a feature class.

GIS Tutorial Chapter 7:

Chapter 7 of the GIS tutorials was about digitizing. The first tutorial involved editing features to move a building’s polygon. This is done by using the move tool and clicking the select button, then clicking on the building bookmark that they provided. Following this, you rotate the features next as well as add more vertex points and split features. This tutorial was exceptionally challenging while dealing with the polygon editing because of how stubborn the tool could be when trying to adjust the shape. Tutorial 2 was similar but involved creating a polygon feature class and fields using the Create Feature Class tool and applying the given settings. Following this, you utilize the trace tool to outline an entire area rather than a particular building. Tutorial 3 was the easiest of this chapter because all you had to do for this tutorial was use the smooth polygon tool and apply the settings that they provided and click run. The final tutorial, tutorial 4, uses the coreference tool to adjust the CAD drawing and then export the file. The georeference tool allows you to adjust the group and add control points. These control points give the ability for the CAD drawing to be highlighted and form a rough shape of the designated building. You finish this tutorial by exporting the file and then classifying the layers, which display the spaces of each room more accurately. To finish this tutorial and this chapter, you simply click the transform button found within the modified features pane to move the drawing to its precise location.

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GIS Tutorial Chapter 8:

Chapter 7 is about geocoding and only has 2 tutorials; however, it is still complicated and was one of the more challenging chapters so far. The first tutorial was about geocoding using zip codes. This tutorial began by using the create locator tool and inputting the settings that the textbook provides. You can then view this locator after clicking run within the locator tab. In order to actually geocode the data by zip codes, you must next click the geocode addresses tool and once again apply the various settings. After changing the symbology for the new layer, you can view the individual mark for each zip code centroid. You must then rematch attendee data by zip code by right-clicking attendees, data, and rematch addresses. You then input the number 15213 and click the match button. To finish this tutorial, you open the collect events tool, apply the given settings, and click apply to count the zip codes and apply graduated symbols for the given marks. The next tutorial, tutorial 2, is similar to the previous tutorial however, this tutorial is about geocoding with street addresses rather than zip codes. Once again, you first open the collect events tool and apply the necessary settings, and run the tool. You then open the geocode addresses tool, apply the settings, and click run. For this one tutorial, you must select the minimum candidate and matching scores and finally produce the final results and view the map.

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GIS Tutorial Chapter 9:

This is the final required chapter for this course’s discussions and was surprisingly easy compared to previous chapters. The first tutorial used the pair-wise buffer tool and inputted the given settings to estimate individuals who live in close proximity to the nearest pool. You then click select by location and apply the settings and click summarize to finish the first tutorial. The next tutorial is very simple and involves adding a buffer ring around the same map points as the previous tutorial. You can simply search for the multiple ring buffer tool, apply the settings, and then use the spatial join tool to join attributes and summarise data inside the ring. The next tutorial was the most challenging of this chapter for me, but was still straightforward. The first step of this tutorial was to create multiple-ring service-area polygons. The select by attributes tool does this: applying the settings, clicking the service area layer, clicking input data, clicking import facilities, and applying all the settings. The next step is to join service areas and pool tags by spatially using the spatial join tools and selecting pooltags. After this step you must calculate pool use for statistical areas within the attributes table, then make a scatterplot in the features layers data tab in the visualize group, and finally fitting a curve to the data points by opening the chapter 9 data and inputting data for Beta. The next tutorial is using Network Analyst to locate facilities. You must go into the input data group, click import facilities, and apply the settings, then import demand points and apply the settings, then adjust the types and run the mode. You must then analyze the optimal solution for this by opening the various attribute tables and using the summarize tool. The final tutorial is forming data cluster analysis which is done by using the Multivariate Clustering tool, applying the settings, and interpreting the clusters by adjusting the clusters in the label column. 

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Chapter 4

This chapter focused on creating ArcGIS projects from scratch, whereas in previous chapters, we just worked with maps through premade maps and files in the tutorial folders. This chapter also taught me how to modify the attribute tables using the data that we imported for analysis from Maricopa County, Arizona.  This also included learning how to join tables from a data table to a feature class table.

Chapter 5

This chapter got gradually more difficult as I completed it. It focuses on the different geographic coordinate systems and world maps you can use in ArcGIS. We were introduced to the Hammer-Aitoff map as well as the Robinson world projection and U.S. map. When working with U.S. Census data for Hennepin County, Minnesota, and fixing up the data using Excel, this is where I found the part of the chapter difficult due to forgetting to rename two columns or something else, which led to issues with creating the choropleth for Male and Female Bicyclists.

Chapter 6

Chapter six was easier and more of a breeze than the previous chapter. It focused on creating study area block groups which I found helpful. Parts of neighborhoods that were both outside of the outlines of Upper West Side were able to be included inside the study area using the Select by Location tool.

Week 5

Chapter 4

Chapter 4 helped me understand how much of GIS work happens through the data behind the map, not just the map itself. I worked more with attribute tables, fields, and joining data from different tables. I also learned how to calculate new fields and use the data to display specific information on the map. At first, keeping track of the different tables and fields was a little confusing, but once I could see the changes reflected on the map it made a lot more sense. I think working with attribute data like this will be useful because it lets you take a large dataset and actually pull useful information out of it.

Chapter 5

Chapter 5 focused more on spatial data and the different ways geographic information can be stored and brought into ArcGIS Pro. I worked with coordinate systems, projections, shapefiles, XY coordinates, and other data sources. One thing I noticed in this chapter was that there are a lot of small steps involved in getting outside data into the right format before you can actually use it. The Census data section especially showed how data from another source can be joined with geographic features and then represented visually on a map. Some of the steps were harder to follow because the book does not always match the current version of ArcGIS Pro exactly, but figuring out where the tools had moved also made me more comfortable navigating the software.

Chapter 6

Chapter 6 felt more focused on actually analyzing and combining the data that was prepared in the earlier chapters. I used more geoprocessing tools, including tools for selecting, merging, clipping, and intersecting features. I thought this chapter made the purpose of some of the previous work clearer because instead of just adding information to a map, I was using different layers together to answer more specific questions. The tabulate intersection work was also interesting because it showed how GIS can calculate information based on where different geographic areas overlap. There are still a lot of tools and options that I would probably need instructions to remember right now, but I am starting to understand what the different tools are actually doing instead of just following the steps.

Week 4

Chapter 1

Chapter 1 was mostly about getting familiar with ArcGIS Pro and learning how to navigate the different parts of the software. We worked with layers, attribute data, symbols, labels, and both 2D and 3D maps. The health care clinic example was interesting because we could look at the locations of clinics along with other information about the area instead of just seeing points on a map. I also liked the 3D population density map because the differences were easier to visually notice when they were represented by height. I did have some trouble finding certain tools because there are a lot of different tabs and options in ArcGIS Pro, but going through the tutorial helped me get more comfortable navigating it.

Question: When is a 3D map more useful than showing the same information on a regular 2D map?

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Chapter 2

Chapter 2 focused more on how the information on a map is actually displayed. We worked with symbology, labels, choropleth maps, dot density, and visibility ranges. One thing I found interesting was how differently the same type of data can look depending on how it is symbolized or categorized. For the New York City land use map, the different colors made it easier to distinguish between types of land use such as commercial, manufacturing, parks, and residential areas. Having the borough and neighborhood boundaries along with the land use data also helped give the map more context. This chapter was a little more difficult for me because some of the options in ArcGIS were not always where I expected them to be, but I got more familiar with working with layers and their properties.

Question: How do you decide which type of symbology is best for a dataset without making the map too complicated?

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Chapter 3: Maps for End Users

Chapter 3 was different from the first two because it focused more on how GIS information can be shared and presented to other people. We worked with layouts and also used ArcGIS Online tools such as StoryMaps and Dashboards. I liked seeing how the work done in ArcGIS Pro could be used in an online format instead of only staying inside the desktop application. The Ground Crew Dashboard was probably the most interesting part for me because it put several ways of looking at the data in one place. The dashboard included the locations of service requests on a map, information about individual requests in a table, and a chart showing the age of the requests. Seeing these together helped me understand how a dashboard can make geographic data easier to look at and understand without needing to work directly in ArcGIS Pro.

Question: When would a Dashboard be more useful than just sharing a regular map?