Checkpoints are a powerful GPSLog Labsfeature for analysing your activity, they can:

• Split activity into segments for comparison, without affecting the other statistics such as overall mileage and duration.
  This would not be the case if additional places were created as extra activity records would be created.
• Compare your performance on a segment (such as a hill climb) for different routes.
• Checkpoints are assigned on a route by route basis so they only cut the activity of interest.

The easiest way to explain how checkpoints work is to run though a few examples: Once you've uploaded some activity to GPSLog Labs, you next need to assign a route to the activity. Once that's done, you can go to the Splits tab of the route detail page and click the Add Checkpoint link.

Then, create a new checkpoint by clicking on a point on the map or a stop on the log file.

Checkpoints work just like places. The activity inside the circle will be ignored, and the circle has to be big enough for all the logs to pass through it, otherwise they won't be recognised.

After saving checkpoints at the beginning and end of the climbs, the route map now looks like this:

On the route detail Splits tab, a summary of the splits is displayed.

You may need to click the "Regenerate Splits" button, which will reprocess all the activity with the new checkpoints. This may take some time, so there's an equivalent button on the activity detail page's Splits tab that will reprocess only a single activity.

Clicking on the From or To checkpoint will bring up the split detail page. This page combines activity in both directions along the segment and lets you see maps, altitude profiles, trend graphs and other stats.

Checkpoints can be used to analyse short segments too, such as laps around an oval, or runs up and down a mountain (skiing or mountain biking, for example.)

Another use is chopping off the ragged ends of a run, like in the following example where, when entering the city, the GPS signal becomes unreliable. By adding a checkpoint at the end of the path I can avoid the messy log file and also the disruption to my times caused by traffic lights and pedestrians.

This is a tricky area of the site to describe, but it's really useful, so have a play with it and if you have any questions, please let me know.

A few little changes to note while I'm busy working on something big and pretty cool:

• The minimum split time between checkpoints on a route has been changed from 5 minutes to 1 minute, so you can now record splits as short as laps around an oval, assuming you're not too fast that is.
• Distances and times are now displayed with full precision in the splits detail table.
• The mobile page now has a "Recent Uploads" list, so you can check them quickly when uploading from a phone.
• Route "average" distances are now only shown if the logs are similar in length, otherwise the range of distances is displayed.
• I've added columns showing the last logged date and scheduled count for routes when selecting them for goal tasks.
• The next scheduled task for a goal is displayed in the goals table and on the summary page for quick reference.
• The goal tasks graph now has a link to zoom it in to a view of this week.

I've just added a really useful feature to GPSLog Labs: The "Comparisons" tab for an activity page now actually shows some useful comparisons in a "dashboard" format.

For each of the "standard split" distances (5 km, 5 miles, 10 km, etc.) the speed/pace and time for this log are displayed and compared to that for the other activity on the same route and/or sharing the same tags using a box plot.

The above screenshot shows the speeds for that particular run using solid dots on the box plot, and indicates it was the fastest for that route when stops are removed, but that there was a long stop somewhere between the 8 and 10 km splits that made it the slowest over those distances (the smallest value is on the left of the graphs, so rightmost is best for speed and leftmost is best for pace.)

Comparing it to all the activity tagged with Run, not just along that particular route shows it was in the top 25% (after taking out the stop):

The route comparison shows two extra splits that are not available when comparing to the tag, the total distance (10.6 km in this case) and the half-way point (5.3 km). These assume that all activity on the route is about the same length, so aren't meaningful for a tag and may also not be very useful if you have a route which varies a lot in length.

Some other recent updates to the site:

• Pages with many tabs will have some of the tabs hidden to save space. Click the "more >>" button to show the rest.
  
  
• The unknown routes page now lets you filter by tag.
• When setting up a task for a goal, you can now filter the possible routes by place. This means that you can quickly find a route of the desired distance to complete the task and aren't overwhelmed by routes from places you don't need.
• There are a couple of QR Codes on the site now to help get the urls into your mobile device. Scan the following QR code to go to the mobile version of GPSLog Labs, for example.
  
  There is also a QR code for the unique upload email address for your device on it's detail page.
• When adding tasks from a training program to a goal, or creating a new goal from a training program, you can now see a preview graph of the tasks involved:
  
• The tag detail page has a new Splits Graph tab that shows a graph of all the activity speeds/times at standard split distances, together with lines indicating the distribution (10th, 50th, 90th percentiles).
  
• The standard split distances now extend from 50km to 300km (50mi to 200mi) to make them more useful to cyclists and longer distance activities.

As always, please send feedback and suggestions to feedback forum.

• Activity maps now have milestone markers:
  

  These are displayed every 1 km or 1 mile depending on your units setting and will automatically be hidden as you zoom out.

  Note that the milestone markers are displayed by default on shared maps you have embedded into your own site, if you don't want them displayed regenerate the embed code or edit the <iframe> src attribute and add &show_milestones=false to the end of the URL.

• Split times are computed for the first 5km, 10km, etc. of your activity so you can compare performances regardless of the tags, routes or final distance. These are displayed on the activity "comparisons" tab and on the new splits tab for tags. This will let you find for example, the log with the fastest 10km time you have run by going to the Run tag, and sorting the splits by 10km.

  These distances are probably only useful for runners, if you have any suggestions on how this should behave for other sports please let me know.

• Activity split tables now show the cumulative distance/elapsed time:
  
• Graphs throughout the site now have a filter that lets you display only one year at a time once you have been logging your activity for more than a year:
  
• I've also done a general tidy up of forms on the site, giving them a layout and improving the way they display for smaller browser windows.

I've added a new tab to the route detail page in GPSLog Labs that compares the distance splits for all logs in the route.

This allows you to see the speeds over each section of the route for each log. Each column is coloured to indicated min/avg/max in white/green/yellow respectively. This allows logs that are faster or slower than normal to be easily identified.

For routes that display pace instead of speed, the pace over 1km (or mile) is displayed, i.e. for longer splits, it is not the time to cover the whole split distance.