I am teaching a course where I am using ArcGIS Online and Community Analyst Online to introduce students to GIS applications across a range of disciplines. I have an assignment I am trying to trouble-shoot that is based on this great article on Esri Insider: What Do Americans Do on the Fourth of July Weekend?
In the article, Praveen Srivastava uses Community Analyst to find high prevalence counties for three groups: Outdoorsy People, Power Grillers and Shopaholics. I led my class through the exercise of mirroring the article and finding similar groups of counties using the Smart Map Search tool. No problem. We all then shared our three groups of counties to our ArcGIS Online accounts in order to make a map containing all three groups. Once again, no problem. In order to create the map with all three layers we had to open each of the maps shared from Community Analyst and save the data layers, the create a new map and add the three layers. No problem.
Now for the problem. And if you're interested in playing along, here's a link to the ArcGIS Online map that I am using: 4th of July. The map and all of the data layers included in it have been shared to "Everyone".
The next step was to use Derive New Locations to create a new layer that would only include counties that met the original Smart Map Search criteria for all three layers (Each layer has a field named "matchField" that contains the data value "match" when a county meets the respective criteria). As I was creating the assignment, I ran Derive New Locations and created a layer that has 99 records (counties), which sounds and looks reasonable. That layer is named "Shopaholics, Power Grillers and Outdoorsy People". I believe the Dereive New Locations query I ran is as follows (you can see a screenshot of most of the query in the attached pdf file):
- Shopaholics completely within Power Grillers, and
- Shopaholics completely within Outdoorsy People, and
- Shopaholics where matchField is "match", and
- Power Grillers where matchField is "match", and
- Outdoorsy People where matchField is "match".
When the class and I worked through these steps during class it did not turn out as I had intended. The layers that result from the query have thousands of records, rather than the 99 or so that I expected. There are what look like duplicates of many of the records (lots of them). I don't know whether I recorded the query wrong or the query is (for some unknown reason) now not working properly. And if I did record it wrong, what was the query that created the layer with 99 records - which is exactly what I wanted?
If you check out the map and the assignment you will see that I then intend for the students to append Tapestry data to the selected counties, create a Tabbed Map Series web app from their map and then include text that describes the layers/tabs. (There are also some reflection questions listed on our LMI, to round out the assignment).
I could really use some help with this.
Thanks in advance,
Department of Liberal Studies
Cal State University San Marcos