Skip to main content

Finalizing Thoughts on the Elevation API Datasette Enrichment for Ham Radio QSO Paths

 I've outlined the work on the ham radio QSO Google Maps Elevation API Datasette Enrichment  (try saying that 3 times fast) over the last several days.  What I haven't talked about much, but thought about pretty often is what the released elevation enrichment should do. Here goes.

The Datasette enrichment will store the JSON data returned from the Elevation format in a database column named 'elevation'. Remember, the enrichment is taking two coordinate pairs that form a QSO like the brown line shown between Villa Nueva, NM and Idaho (KJ7DT's QTH).


It then determines the endpoint of a line that only covers the first 200 meters of that path, shown as the blue line below:


(Yes, 8 year-old Tawnse and I were sitting on the side of the 'cliff' on the other side of the Pecos River from the campground during that QSO. Yes, Tawnse does have a lower center of gravity than I do and led me up that path. Yes, I did have a heck of a time getting back down once I turned around and saw where I was. Please reference Tigger. Up the Tree. With Roo. for a literary example.)


Using that shorter path segment, the enrichment calls the Google Maps Elevation API for a 'path', asking for 200 samples to be returned, and winds up with JSON data formatted as shown.

{
   "results" : 
   [
      {
         "elevation" : 123.6165237426758,
         "location" : 
         {
            "lat" : 37.72489522009444,
            "lng" : -122.4229361744053
         },
         "resolution" : 9.543951988220215
      },
      {
         "elevation" : 123.4337463378906,
         "location" : 
         {
            "lat" : 37.72489438728456,
            "lng" : -122.4229250613661
         },
         "resolution" : 9.543951988220215
      },...

From there, I've written at length over the last few days about how to make an elevation chart like the one shown below. 






Only the data labeled as "elevation" is used in the chart even though there's more information to be had in the JSON response. At the moment, that data is simply being discarded. Other users of the enrichment might have a need for it. Other users might also have different uses for the data altogether than an elevation chart in base64 text encoded png format, (the sole output of the enrichment at this time.) 

So! The enrichment will be modified to simply store the JSON data. I'll make a second enrichment that will create the charts I require. The inputs to datasette-enrichments-gmap-elevation will be:

latitude1,longitude1,latitude2,longitude2,optional_sub_path_length_default_200_m

Where the first four arguments are the start and end coordinates of the entire path, and final, optional argument specifies how many meters long the path segment should be and defaults to 200 m.

The output will simply be the returned JSON data stored in a column titled 'elevation'.

I'll create a second enrichment datasette-enrichments-elevation-chart that consumes JSON elevation data and produces text encoded png charts.


Fun References:

KML/KMZ revelation inspired by the POTA from the above map.

UAP siting on the same trip




Labels:

Comments

Post a Comment

Please leave your comments on this topic:

Popular posts from this blog

The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1.  While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero.  This is typically explained in the following way.  While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare.  That doesn't stop us from looking for them though! Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2].  Cabrera was utilizing a loop type of magnetic monopole detector.  Its operation is in...
1 comment
Read more

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems , there seem to be fewer explanations of the procedure for deriving the conversion, so here goes! What do we actually want? To convert the Cartesian nabla to the nabla for another coordinate system, say… cylindrical coordinates. What we’ll need: 1. The Cartesian Nabla: 2. A set of equations relating the Cartesian coordinates to cylindrical coordinates: 3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system: How to do it: Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables. The chain ...
11 comments
Read more

More Cowbell! Record Production using Google Forms and Charts

First, the what : This article shows how to embed a new Google Form into any web page. To demonstrate ths, a chart and form that allow blog readers to control the recording levels of each instrument in Blue Oyster Cult's "(Don't Fear) The Reaper" is used. HTML code from the Google version of the form included on this page is shown and the parts that need to be modified are highlighted. Next, the why : Google recently released an e-mail form feature that allows users of Google Documents to create an e-mail a form that automatically places each user's input into an associated spreadsheet. As it turns out, with a little bit of work, the forms that are created by Google Docs can be embedded into any web page. Now, The Goods: Click on the instrument you want turned up, click the submit button and then refresh the page. Through the magic of Google Forms as soon as you click on submit and refresh this web page, the data chart will update immediately. Turn up the:...
Post a Comment
Read more