Kev's Development Toolbox

October 8, 2019October 8, 2019

Revisiting my spotviz.info webapp: visualizing WSJT-X FT8 spots over time – part 5: MongoDB Aggregate Queries

Now I have my http://www.spotviz.info app up and running with some collected spot data for testing, one of the first things I want to enhance is the date range selection for visualization, and specifically, adding more data to the heatmap to help you pick a good date range with available data.

The heatmap display I originally added gives you a visual representation of which days have data to view, but it doesn’t help you pick a time range within that day where there’s data. Here’s what the heatmap looks like right now:

The darker the color the more data there is for that day. The problem as it is right now though is that say for one day you ran WSJT-X for 1 hour between 1pm and 2pm and received spots from 2000 stations. Without knowing that there’s only data between 1pm and 2pm, you could select a range of 9am to 6pm for playback, and you’d get nothing displayed on the map until it animated through the 1pm to 2pm block and then a gap of nothing again.

My first enhancement here is to show the earliest and latest signal received times for a given day, to help you pick a good range.

The original MongoDB query (which I discussed here) retrieves a count of spots per hour for a given day:

db.Spot.aggregate( [   
   {$match: {spotter: "kk6dct"}},
   {"$group": {
     "_id": {
       "$subtract": [
         { "$subtract": [ "$spotReceivedTimestamp", new Date("1970-01-01") ] },
         { "$mod": [ { "$subtract": [ "$spotReceivedTimestamp", new Date("1970-01-01") ] }, 1000 * 60 * 60 * 24 ] }
       ]
     },
     count:{$sum: 1 }
   }
 }
])

There’s only one calculated value returned in the results in this query, count, but in order get the earliest and latest spots per day, this is a simple as adding two more calculated values following the return of

count : { $sum : 1 }

so the last part of the query is now:

    count : { $sum : 1 },
    "firstSpot" : { "$min" : "$spotReceivedTimestamp" },
    "lastSpot" : { "$max" : "$spotReceivedTimestamp" },

Done!

October 3, 2019October 3, 2019

Moving GoDaddy DNS to AWS Route 53

Before changing the DNS settings on GoDaddy, set up Route 53 to manage DNS for your domain first, because you’ll need the AWS DNS server names when updating the GoDaddy DNS config.

In the AWS Console, go to Route 53, then Hosted Zones, and press the ‘Created Hosted Zone’ button:

Enter your domain name, select ‘Public Hosted Zone’ and press ‘Create’:

At this point Route 53 will have assigned a list of DNS nameservers for your domain – remember this list for when you update the GoDaddy config

Next, press ‘Create Record Set’, select Type A record and enter the name of your subdomain, e.g. www, and enter the IP address of your server that this name should resolve to:

Now let’s update the GoDaddy config. By default, here’s the DNS entries managed by GoDaddy when you register a domain with them:

First step, cancel the GoDaddy nameservers. Do this from the ‘Change’ button:

Change the type to Custom:

Then enter the dns server names from Route 53 and press ‘Save’. You should now be done. Assuming the setup on Route 53 has propagated, hit your domain name in a browser and hopefully you’re up and running.