Re: And radar from the first mission when it was a major hurricane
Posted by Chris in Tampa on 8/23/2015, 8:22 pm
ArcGIS has a cache delay:

"There is a 30-minute cache delay on displaying updates to your KML layer."

From: https://doc.arcgis.com/en/arcgis-online/reference/kml.htm

So while the file that is being retrieved is probably up to date with radar imagery about 10 minutes after the scan takes place, and always contains the latest image, you don't see that in ArcGIS until up to 30 minutes later. I should say "up to" that kind of delay. So ArcGIS will miss showing some radar scans as they seem to come in every 5 minutes while the NOAA P-3 plane is out there.

I have set your version of the radar product to currently remove a radar scan after 1 hour. So in the file retrieved in Google Earth and ArcGIS, the radar scan will be removed after that time. However, because of the ArcGIS cache delay it might take an extra hour to be removed. So data could be up to about 1 hour and 40 minutes old. (About 10 minutes after the radar scan was actually taken it appears on your site, then stays in the file for an hour, then displays in ArcGIS for up to an extra half hour) The Google Earth and ArcGIS file will simply contain no content after that. (A blank placemark which shows nothing on the map.)

Eventually I'll probably also do this in Google Maps. Eventually, all recon data in Google Maps, and there will be no delay then in the maps created and managed by the recon system itself. But I couldn't yet figure out how to do the Google Earth KML or KMZ (KMZ is just a zipped KML file, where you can include other things like images) file for Google Maps. I may have to end up taking apart NOAA's KMZ file and saving the images along with the coordinates of the overlay. Then in Google Maps I would have the information to use JavaScript to position the actual PNG radar image so that I could dynamically create a display as simple as having a checkbox or radio buttons to select the scan you want in the side display in Google Maps and it instantly appears on your screen, making it very easy to navigate the data.

I am working full time on bringing the recon display in Google Earth to Google Maps, and it is going well, but there is so much work to do still. It will likely be early next year. I'm already several years behind on it.

I'll probably working on breaking apart the Google Earth files I get from NOAA. The NOAA radar system on their end is automated now so I can start to build the scripts to get very specific on how I manage the data. I'll probably store the files that come into the main part of the recon system differently, along with how they are presented in the archive. I'll break apart the KMZ into an actual image with saved coordinates in order to position the overlay. You will then be able to, in Google Earth, select the radar scan you want with a radio button or checkbox for example and load the image directly from the left side as well without clicking a popup. In fact I might go do that soon. I like the idea of how that would be presented. But there is a lot to change. I would probably have the path, with icons like I have now, but then also have a separate part to load the file like I do now probably. I'll have to think about it.

The problem is the NOAA radar feature was new and at the time I started working on this a year ago, I had no idea how things were going to come across. At first they literally took a picture, with a camera, of their computer display on the plane and sent that out. Then it was an actual screenshot. Now all automated. It's come a long way.

There's 2,000 lines of code, just for the part of the radar system itself that gets the imagery. (The recon system may have tens of thousands) There are around 75 scripts and 1.96 MB of code at the moment for the entire system. But now that I see how data will likely come across from now on, I can get rid of some code and finalize other parts and features.

If anyone has suggestions, let me know.

Things on my list already for ArcGIS display map page:
http://hurricanecity.com/recon/live_radar/arcgis_map/

- Have date of radar.
- Auto zoom in close to the radar image if one plane. If two, average coordinates of two and show wide view that may contain both planes.

And maybe even I'll build a display for the radar display for Google Maps sooner rather that later, we'll see. I might wait until I do it with the whole recon system.
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Radar data from the NOAA hurricane hunters' P-3 aircraft in Google Earth - Chris in Tampa, 8/23/2015, 8:58 am
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