search

saintbyte / openbmap

Automatically exported from code.google.com/p/openbmap
Other
1 stars 1 forks source link

Increase overlay refresh rate in map view #5

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1. Start logging.
2. Go to Map view.
3. Drive around and wait for blue dots to appear as you spot new WiFis.

What is the expected output? What do you see instead?
Expected: a trace of blue dots behind me as I move through an inner-city street.
Instead: no dots in the last few meters behind me; as I move on, they suddenly 
pop up. If moving very quickly, the area does not get refreshed before it 
scrolls off-screen.

What version of the product are you using? On what operating system?
Rev c4f48ccb716e built from source, on Cyanogenmod 10.1.2

Please provide any additional information below.

In the source code I see that apparently the WiFi overlay gets refreshed every 
100 meters. However, this may result in noticeable delays:

Car on motorway: 2-3 seconds
Car in built-up area: 6 seconds
Bicycle: 10–30 seconds
On foot: 1 minute

This may confuse users: at first glance, it looks as if no WiFis were tracked.

I would suggest triggering updates based on time rather than distance. A 
refresh rate between 2 and 5 seconds seems suitable to me. From a user 
experience point of view I would tend more towards 2 seconds (more responsive) 
and increase as needed if resource usage is too high. Optionally, we can still 
introduce a distance threshold of some 10–20 meters (typical error in GPS 
position) and refresh only if it is exceeded.

Btw, what is a typical event delivery rate for WiFi scans? If it is not too 
high (i.e. not more than once in 2–5 seconds), we could just refresh on every 
WiFi update. (Implementing the combined time/distance threshold would then be 
very easy: just lower the distance threshold to 10–20m.)

Original issue reported on code.google.com by mich...@vonglasow.com on 26 Aug 2013 at 2:16

GoogleCodeExporter commented 9 years ago

Original comment by wish7code on 28 Aug 2013 at 9:26

GoogleCodeExporter commented 9 years ago 
Followed a simple approach: refresh overlay every 2 seconds, gpx position every 
second.

If anybody complains about ressource problems on older devices, we could also 
go for a more sophisticated approach..

Original comment by wish7code on 29 Aug 2013 at 8:11