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Class-Specific Resources

Structuring Data for ArcGIS Online

In this tutorial we’ll explore another way of working with data in ArcGIS Online that will involve both importing data and creating data right in the web interface. For this exercise we will use data from page 251 of Tatiana Seijas's study on enslaved Asians in colonial Mexico. We will use a spreadsheet based on Seijas’s work to create a new point data layer and then import that spreadsheet and join it to the points layer. This will allow us to visualize the volume of slaves from the different origin locations that Seijas identifies.

Contents

STEP 1: Creating New Data with ArcGIS Online Map Notes

To begin, navigate to https://www.arcgis.com/ and login to your UCSC-affiliated account. Again, if you have trouble setting up this account or logining in, get in touch with your instructor or the DSC for help.

  1. Once you’ve logged in, create a new map by clicking Map in the main menu at the top of the home screen. When the map opens, save it with the title “Enslaved Asians in Mexico (Origins)” and the tag “history.” After you’ve saved the map, in the left menu area select Content to see the layers of your map—there should only be one so far (the basemap).
  2. Now we’ll create a new layer for adding our point. The way to do this in ArcGIS Online is to use the Map Notes feature. To create this new layer, go to Add > Add Map Notes. Give the layer the name “Chino Slaves Origins” and click Create.
  3. Now you’re ready to add points. Here you’ll want to reference Seijas-p251.csv and move down the rows, adding a new point for each. If you'd like, you can also download a PDF of the page from Seijas that this data comes from. Once you’ve determined where you want to place the new point, use the search box in the top right to move to that location. (Consult the Location Notes column in the spreadsheet for guidance on where points should go. Remember that these are approximate, rather than precise, locations.)
  4. After you’ve searched, the map should move to the location and a search results box should appear. Close that popup and select the Stickpin tool from the left hand menu. Now click in the area of the map you want to place the point and copy the data from the Origin column in the Seijas spreadsheet into the Title field. Click OK.

Point window

  1. Proceed through the rest of the rows in the spreadsheet through this same process: search for the location, close the search results popup, select the Stickpin tool in the left hand menu, click where the pin should go on the map, and enter/copy the data from the Origin column in the spreadsheet into the Title field.
  2. When you’re done, click the small left arrow in the top right of the left hand menu to go back to the list of layers, and click on the Content tab if it is not already selected. You should now see your Chino Slaves Orgins layer in the list.

Map with pins placed

  1. Save your map. Remember, ArcGIS Online does NOT autosave.

When you’ve finished going through the whole Seijas spreadsheet, you should have a map with several pin icons placed around Asia. Now it’s time to import the spreadsheet and join it to our points layer. This will create a new layer that has data attached to points, which we can then visualize in more compelling ways.

STEP 2: Adding the Seijas Spreadsheet and Joining It to Your New Layer

  1. We can add Seijas-p251.csv by selecting Add > Add Layer from File. Select file, then Click Import. Select “None, add as table.” Click Add Layer.

Add CSV layer options

  1. Now, for the Chino Slaves Origins layer, select the Perform Analysis option (it's the button that looks like a map with points on it). Then select Summarize Data > Join Features.
  2. For “Choose target layer” select the Chino Slaves Origins layer. This is the layer that you are attaching data to.
  3. For “Choose layer to join to target layer” select Seijas-p251. This is the data we’re joining to Chino Slaves Origins.
  4. For “Select the type(s) of join” select “Choose the fields to match.” For Target field select “Title.” For Join field select “Origin.”
  5. For “Result layer name” input the name “Chino Slaves Origins Data ([Your Last Name]).”

Perform Analysis window

  1. Click Run Analysis. It may take a moment or two to complete.

You should have a new data layer in your map named “Chino Slaves Origins Data ([Your Last Name]).” You can uncheck the original “Chino Slaves Origins” layer so that you can focus on the new layer. Now let’s style that layer to reflect the data we have.

  1. For the Origins (Data) layer, click Change Style (it’s the button with an overlapping triangle, square, and circle).
  2. For “Choose an attribute to show” select “Slaves.”
  3. Choose the Counts and Amounts (Size) option. It may be selected automatically. (Note: This is the same as the Graduate Symbols style option in QGIS.) There are a number of settings you can adjust. For now, we’ll leave them all at their defaults.
  4. Optional: If you'd like to turn on labels for these points, click on the more icon (...) for the Chino Slaves Origins Data ([Your Last Name]) layer and then Create Labels. You'll have the ability to customize label size and placement. When you're done click OK.
  5. Click Done and then save your map.

You should see your points displayed by size according to the number contained in the Slaves column.

Remember, you can always select a different basemap if you think another option would make your data more legible. Here I’ve selected Light Gray Canvas.

Points on map reflect data

  1. Now that you've plotted the approximate origins of each of these captives, draw their trajectories. Each line should go first to Manila (in the Philippines). Then there should be a single line that goes from Manila to Acapulco, Mexico, in order to represent the route of the Spanish galleons upon which the captives traveled. You can then weight the lines based upon the data in Seijas-p251_lines.csv. Hint: This process is exactly the same as creating the points and then joining them to the spreadsheet for the data to weight them. Simply create a new Map Notes layer, draw lines (instead of dropping points) based on the information in the lines spreadsheet, name the lines, then join the lines spreadsheet to the new Map Notes layer. The result should look something like this.

Route displayed on map

STEP 3: Sharing Your Map

When you've finished your map, you can share it in a couple different ways.

  1. In the top menu, select Share (it's just to the right of Save).
  2. To share the map via a URL, simply copy the URL displayed under "Link to this map." Note that checking "Share current map extent" means that anyone who navigates to that link will see the map at the zoom level and focus you currently have set. You can go back to your map and adjust the zoom and focus to change this. As always, be sure to save your map!
  3. To share by embedding your map on another website, you will first need to check "Everyone (public)" under "Choose who can view this map." Then near the bottom, click Embed in Website. There you'll see a number of settings which you can leave alone or adjust as you desire. When you have everything set, click Copy by the code field under "Copy and paste HTML to embed in website." Then paste that code into the website where you want to embed the map.

You may also notice the option to Create a Web App from your map. We won't be discussing that option here, but the next tutorial will deal with one of those apps—StoryMaps.