COVID-19 – geoMusings

Personal Geography

2020-05-062020-05-06 by Bill Dollins

Human geography or anthropogeography is the branch of geography that deals with the study of people and their communities, cultures, economies, and interactions with the environment by studying their relations with and across space and place.
Wikipedia (https://en.wikipedia.org/wiki/Human_geography)

I was catching up with my friend and former boss, Tony Quartararo, a couple of days ago when our discussion got around to behavioral changes we have made in response to the COVID-19 pandemic and subsequent lock-downs and social distancing guidelines. Not surprisingly, given our backgrounds, geography figured in strongly.

The use case we discussed was grocery shopping. Both of us admitted to limiting our choices of venue to those that we knew from memory, so that we could gather groceries and proceed to the exit as expeditiously as possible. This has the effect of geographically constraining our choices to our immediate locality. Even in the case of large chain grocers, the floorplan of each store varies widely.

Attribute Transfer in PostGIS Using Spatial SQL

2020-04-062020-04-06 by Bill Dollins

Data conflation is a meat-and-potatoes task in most GIS workflows. There are numerous reasons one might need to get data from one data set into another. Perhaps you want to attach a new geometry type to existing attributes or a table. Or maybe you need to pull attributes from one or more data sets into a single, “master” version. I have seen this latter use case referred to as “attribute transfer.” In an interactive, desktop setting, this can be tedious, but it’s a task at which spatial SQL excels.

Here is a simple example that uses just one line of spatial SQL (or two lines if you need to add the column) to do the heavy lifting. First, some table setting. This example takes the number of confirmed COVID-19 cases from the Johns Hopkins university county-level data (a point data set) and transfers it to a polygon data set of the US counties. There’s one caveat at the end of this post.

Watching COVID-19 Data for Your County with PostgreSQL and Node

2020-04-022020-03-31 by Bill Dollins

I have addressed the topic of triggered notifications a couple of times on this blog previously. I’ve taken the opportunity to apply the technique to a current use case – the ability to get notifications whenever the confirmed count of COVID-19 cases changes in my county or surrounding ones.

I am basing this workflow on the Johns Hopkins University county-level data available as an ArcGIS feature service here: https://services1.arcgis.com/0MSEUqKaxRlEPj5g/arcgis/rest/services/ncov_cases_US/FeatureServer

Using the “f=geojson” parameter, it is possible to download the data in a format (GeoJSON) that is readily consumable by OGR. As a result, I was able to initiate a core workflow using the following steps.