Getting acquainted with QGIS

The mapping quest: 

What to map: I’m interested in the population density of school-aged children compared to per-household property tax contribution (let’s use Brooklyn, NYC). The reason it’s on my mind: a recent conversation I had with a friend who remarked that his school taxes were high (he felt) compared to the number of students in (his) area, and (he suggested) mismanagement and/or misappropriation of funds.  Who knows, on all counts.  Certainly, not I.  I am curious. 

How to map: Sticking with the basics for now, I only aspire to plot some data onto a static graphical streetmap. A good way to show this information might be to illustrate school-aged density on a map (with color saturation), then overlay an average $ amount of property tax assessments in the same location(s).  This does suggest the map would need to be interactive, but I plan to start with a static map due to my complete lack of experience with mapping.

Finding the data: I thought this information – child numbers and property tax figures – must surely be available in some form from NYC’s open data sets, so I set that aside for a moment and concentrated on the tools to eventually wield and display this data.  But to be on the safe side, I quickly peak in NYC OpenData. Ugh, this is going to be tougher than it looks. Tax with location information easier than child numbers. And child number with location data? ???

Acquiring the tools: Based on the summary of information in the “Finding the Right Tools for Mapping” article, I decided to try the QGIS application.  I believe in free, and I also have a Mac.  Having an older Mac, I found that I had to first download Python to use the version of QGIS available to me.  So I endeavored to install that. I had to choose an old Python too. Python told me me cheerily that its installation was successful, and I took it at its word.  I moved on to QGIS.  Because my OS is so old, I had to look for “previously released” installers, which I searched for by date, using a date in about the same timeframe as the Python version I just installed.  I settled on the “official” installer vs the “kyngchaos” installer, not knowing the difference.  And ‘kyng chaos’ is not a computer-install friendly name, in my opinion. 

Well, having downloaded an ancient (2018) version from the QGIS archive, I looked in the directory and opened the “read me” file, as I was bade. Besides a bunch of notes for people who know a lot more than me, of note is that the text was signed “William Kyngesburye”, so that’s kyngchaos and I don’t know, maybe he’s OK. I clicked over to his website (it’s not a virus) and he’s quoted Tarzan and brandishes a yin and yang symbol.  Admonishments duly noted, I proceeded to install.  After some typical “you’re not allowed unless you really want to” hijinx from my anxious computer settings, I proceeded to install buckets of software packages from kyngchaos. Once that was done, and becoming a bit nervous from ignoring several “Very Important” messages in large red text, I attempted to open the newly installed QGIS application. Well, it opened!  Amazed.

Learning QGIS: After I opened QGIS, of course I realized I had know idea how to use it.  I went off to find the training guide at the QGIS website.  … Some time later, I had a lovely export of a png map of the first training software exercise, using the provided test data (that I had to download separately – because old computer). The training set uses data about lakes on a map of Alaska. Of course I checked with the oracle, Google Maps, to confirm that these are actual lakes on an actual map of Alaska. 

Because my version of QGIS is necessarily older than the current one, using the training guide presents challenge, as I’m teaching myself to use an unfamiliar system with unfamiliar terms on a platform with not insignificant differences from the manual.  For example, project files are now saved in a zipped format, but in my version they are saved out uncompressed.  No big deal, but the file name they mention is different and for several minutes I searched and searched for something… that wasn’t there and wasn’t going to be.  Another example: the Navigation tool bar and Menu have been updated (in the manual and current version).  Disorienting, but OK. Another: the Layer properties inside some data types (notably the vector layer which used a .gml file) are different.  Well, I can pretty much guess… but you get the idea.  Builds character.

I decided I need to learn more about QGIS to do anything with it from any available open data source.  But do I appreciate more what people do when they start from zero and build a map? I do!

… Then I thought about commercial more WYSIWYG solutions… I watched the Tableau software ‘sizzle reel’/”see it in action” video.  Wow technology!