Explore Posterous

New GPS Track Filters

GPSLog Labs now has a powerful and customizable filtering feature to clean up errors in your logs caused by bad GPS signals.

There is a new menu option on the log detail page that will let you edit the filters applied to that log:

The following graph comes from a log recorded while running and shows the kind of noisy data that is often present.  The incorrect speeds mess up the maximum speed, average speed and distance stats and often correspond to a bad trace on the map too.

Discard filters

The first filters you can choose from will discard invalid points from your log and then interpolate the speed and course between the remaining points.

After applying those filters, the speed vs time graph looks a lot better (discarded points are colour-coded to match up with the chosen filters):

Post filters

The second filtering stage applies an average function to the newly cleaned up data.  Smoothing the speed graph will give you a more reliable average and maximum speed statistic and also improve the distance and time split data, but won't clean up the trace on the map or affect the total distance.

The original speeds are shown on the graph below as a light blue line, and after applying a median filter, the thick blue line has been smoothed (no discard filters were applied for this graph). 

This graph shows the final results when both discard and post filters are applied:

Existing logs

The new filters will only take affect for new uploads, existing logs will retain the data from the old filter that GPSLog Labs used to apply until they are reprocessed.

Also, the discarded points from the old filter will no longer be shown on the Speed vs Time graph on the log detail other graphs tab.  This information is only available now for logs using the new filter system from the Filters menu item.

Try it out

I suggest using a simple Speed Median filter initially, as that will clean out a lot of noise, setting the window time parameter to a larger value will smooth the speed more.  I'll be describing the other filters in future posts.

As always, let me know if you have any difficulties or suggestions, and I hope this new feature helps you get more out of the site and your GPS logger!

-- Tom

Fancy route selection dialog

I've just updated the select route dialog when editing the processed activity for an uploaded log to make it nice and graphical, instead of an unclear dropdown list:

This will show the thumbnails for each route to help identify them, and also highlight in green the routes that are closest in length to the logged activity.

If you've assigned tags to the activity, the possible routes will be filtered.  You can click the Show all routes link if you need to see other routes.

-- Tom

Tag and route inference

GPSLog Labs has always made some basic attempts to automatically assign a route for a log segment if it can:

• If there is a single route between the start and end places of the log it will be assigned automatically.
• If there are no routes between the start and end places, one will be automatically created and assigned.

And now I've just added an experimental feature that will try to guess the route after you assign a tag.  This is useful in those cases where you have 2 (or more) routes between places, say one by car and one by bike.  The above automatic assignment won't work in these cases, but if you tell it whether it was by bike or car by tagging the route, it will look again for routes using only the assigned tags.

This works in reverse too, if you assign a route that always has a particular tag associated with it, then the tag will be automatically filled in too.

So, it'll vary depending on your setup, but you should be able to select the route in many cases and have the tags automatically assigned and select the tag in other cases to have the route automatically assigned.

Let me know if you come across any issues with this change, and hopefully it makes things a little easier.

-- Tom

Upload processing redesign

Well, the inbox redesign mentioned a few weeks back turned out to take longer than planned, but the end result is a huge improvement in the way you manage your log files with GPSLog Labs and the "inbox" doesn't really exist anymore.

I'll post a quick tutorial soon to show the basic steps involved in uploading a log and processing it, but for now, a summary of some of the major changes are as follows:

• Activity is automatically extracted from uploaded log files and no longer needs to be "confirmed" before it shows up in the rest of the site.
• You get much more direct control over the editing of the extracted activity.
• Places will automatically be created based on your uploaded logs.

This last one is a biggy and results in a big change to the way you use GPSLog Labs.  GPSLog Labs now "asks for forgiveness, not permission" and will create a new place whenever a log starts or stops in a location that can't be matched to an existing place.  This means that you can get up and running with the site much more quickly.

When GPSLog Labs creates a place, you can either give it a name and keep it or if you don't want a place at that location, you can swap it for the correct place that should have matched.

Tom

Inbox redesign stage 1

Just a quick note to say that the first phase of the redesign of the GPSLog Labs Inbox is now live.

The tabs have been renamed and some of the less used tabs have been changed to links at the bottom of the main remaining tabs.

There'll be some more big changes soon, until then, the documentation is going to be a little out of date.  Please contact me if you get stuck anywhere and need some assistance before then.

-- Tom

Log Timezone Changes

I've just changed the way that GPSLog Labs detects the local timezone for a log to make it more reliable.

Each place now has a timezone field and this is used to set the default timezone for any logs to or from that place (kind of obvious really...)

When you're adding a new place, you can choose the timezone or just click the "Auto-detect" button which will use the geonames.org web-service to determine the timezone.

I have been able to fill in most timezones for places that have been created to date.  Have a look at the Places configuration page though as you may have one or two that you'll need to set yourself.

If a log doesn't match any places it will default to the timezone you've set in your Profile page, and the timezone for a log can always be edited if you want it to be something different.

-- Tom

Updates for September 10th

This post outlines a few of the recent updates to GPSLog Labs:

• I've added a new menu to the uploaded log files in the Inbox confirmation stage.  This allows you to quickly perform tasks on the uploaded log file should you need to by simply moving the mouse over the log file heading:
  
  

• Graphs now shade the middle two quartiles of the data, instead of showing +/- one standard deviation, where the distribution is not Gaussian. i.e. everywhere except distances along a single route. Blame Nassim Nicholas Taleb.

• There's a Battery Cycle Duration vs Date graph on the device's Battery Life Graph tab as I was curious to see if my batteries might be deteriorating with age (they're not yet.)

• There's a new Total Stop Time vs Date graph on the route detail Stops tab.  This can show you if your amount of stopped or resting time is changing over time.

• Goal graphs now have a dot showing the required amount to meet your target in the remaining time. The lines show the overall average so far (blue) and the average target required (orange), the dots reflect what you need to do per week/month to meet the target based on what you've done so far and how much time you have remaining:
  
  

• Goals are now shown on the week's activity "dashboard" on home page.  This lets you see at a glance how you're tracking against the goals and plan what to do next:
  
  
  This shows: the goal title, the difference between your actual activity and the goal target to date, the total activity counting towards the goal this week, a percentage comparison to the weekly target.
  Under the total goal activity for the week are coloured indicators to show what day the activity occurred on. The most recent day is on the right in green, the oldest in orange on the left.

-- Tom

IPhone interface

GPSLog Labs works quite well on the iPhone, but it's not a truly useful mobile experience:

So, I've added a mobile version of the site:

It will take advantage of the GPS in the phone (if available) to show you information in GPSLog Labs that's relevant to your current location (if it can recognise it) and you can also add new places into GPSLog Labs directly from the phone while you're at the place.  Meaning logs you upload later will be automatically chopped without you having to edit them.

You can quickly browse through the logs you've uploaded, view their stats, maps and graphs:

This is just the beginning, expect a lot more useful features soon (and let me know if you've got any ideas too!)

Tom

 

New simplified tab layout

I've reorganised and simplified the tabs on GPSLog Labs, they'd been multiplying and needed to be rationalized.  In case you can't find something, the following is a summary of what changed:

• The Stats tab has been combined into the Reports tab, the old Reports showing up under the Custom Reports subsection.
• Your Devices are now shown at the bottom of the home page, rather than on their own tab.
• There's an Upload button on the home page now, and no longer and Upload tab.

The home page has had a bit of a shake up too, moving the Inbox summary to the right hand panel.

Tom

Route wind effect prediction

There's a new Wind Effect graph on the GPSLog Labs route details Other Graphs tab.

This graph attempts to quantify the effects of wind from different directions on logs along a route. It is intended to assist you to choose a route when bike riding (either to minimise the effect of the wind or to maximise it if you're keen!)

There are 4 lines plotting the relative effect on the overall average speed for the route for different wind strengths. The units are relative and indicative only.

For example, for a log such as the following (predominantly traveling in an east-west and west-east direction):

The computed Wind Effect indicates that the greatest effect will be when the the wind is from the east or west, and the minimum when the wind is from the north or south:

For a route which has a less symmetrical profile, with long sections traveling east and south:

The computed wind effect is more even, but there is a definite advantage when the wind is coming from the west:

The wind model used is pretty primitive and assumes that a headwind has the same effect on your speed as a tailwind, but it's better than nothing.  If anyone knows of any more sophisticated models that could be used, I'd be happy to look into it.

-- Tom