July19th 2016 Improving Performance

December 1st 2015 Qt 5,5,1 is out | | July 21st 2016 Time-Stamp Registration

After a whole lot of testing, debugging and bug fixing during the last half of the year, I eventually regard the core transmission service as stable so that we can now return to some real coding:

To improve the performance of retrieving transmissions from the database we introduce a proxy object, which just has geo-referencing information but not the whole data available from the entire transmission object. It has a reference to the real data, so that upon request the data can be retrieved from the database. Using that proxy element as return type for geo-spatial database searches, we can delay the retrieval of the transmission data until the data is actually needed.

The most common use case of such a proxy object is a photo gallery, which stores the entries by reference, but extracts the image data, only if an image comes into view. With this approach a huge amount of images can be swiftly loaded into the gallery while at the same time memory consumption and response time is being kept low.

So the next step of development is actually adding a gallery view to the app, which shows all the activities recorded and images captured by the app in the chronological order in which they were logged. For that reason we will call it the “log view”.

But before we do that we need to register images, which do not have a gps tag, to a geo-spatial location based on their time stamp. With the time-stamp of the image we perform a lookup in the recorded geo-tracks and if we end up with a hit that is close enough, we identify the respective geotrack location as the location of the image. Also see next blog entry.

December 1st 2015 Qt 5,5,1 is out | | July 21st 2016 Time-Stamp Registration