Track snapshots and multistep undo

...so, let us start with the changes introduced with yesterday upgrade. The first I want to highlight is the "Undo" link when you are editing the track:

From now on, every change you make on a track is stored in a temporary memory with "snapshots" of the track. Snapshots are stored for 10-15 minutes from the moment you made the edit. When you are not happy with the changes you made -- you can reset the track to any of the snapshots (or, of course, reset it to original any time).

Faster Trackprofiler

After 4 weeks in beta testing the new version of Trackprofiler is deployed on the main site. This version brings many new features. I'll mention only one here (and leave the rest for another blogpost)...

In the last 3 months the entire code for GPX/track manipulation is rewritten from Python to Go(lang). The result is that all the track operations, graph and thumbnail reloading and map refresh time is now much faster than before.

More about this update soon...

Private tags and edit quicklinks

A new version is just deployed with a bunch of new features. 

First, you can now browse your own tracks by tags. When you visit your profile page you'll see your own tag cloud in the right column:

By clicking on any tag from the cloud, only your tracks tagged with that tag will be filtered. If you are careful to choose the right tags when uploading the track -- this is a good way to intuitively organize and quickly find tracks.

Next feature is track edit quick links. On any page where a list of tracks is shown, on your tracks you'll see edit icons/links:

  

The title and description can be changed without moving from the page. The icons below the map thumbnail are quick links to the most used edit options.

And the last option... Premium users can now decide for uploaded tracks to be private by default. Just select the checkbox in your profile edit page.

Moving to Leaflet and Openstreetmap

Until a few weeks ago, all embedded maps on Trackprofiler were based on Google maps, but I've made a switch to Leaflet powered maps with MapBox powered layers based on Openstreetmap data and Bing maps layer for aerial imagery. The functionality is more-or-less the same as before.

Why the switch? Google maps is still a great solution which thought me a lot about mapping and online geographical programming, but there are some important reasons why I decided to rewrite a big part of Trackprofiler:

• I believe that Openstreetmap is the future of mapping. It is a great community doing great efforts to create the best map data ever,
• Leaflet.js is a great mapping Javascript library, it is fast and easy to work with,
• Too restrictive terms of service,
• This allowed me to rewrite legacy parts of the application and this, in turn, will help to implement even more new features...

More open source projects

Regular readers of this blog already know, Trackprofiler is not only built on open source components but is actively releasing new open source projects.

Continuing with this trend, here are two new projects for all users of the Leaflet.js mapping framework:

• Leaflet editable polyline: point-by-point editor for (very) big polylines
• Leaflet clicks: a small plugin for custom events where you need to differentiate between single and double clicks. 

Simplify GPS tracks

If you happen to record a GPS track driving on the North Dakota State Highway 46, which...

...is a 123 mile (198 km) road in eastern North Dakota, crossing the Red River Valley between Streeter and Oxbow. It parallels and runs about twenty miles (32 km) south of Interstate 94, and is the longest stretch of straight road in North America. (Wikipedia)

...your track may have tens of thousands of points. Of course, since all of them present a straight line -- only two are important: The starting point and the ending point.

In that case you may use the new feature that is just deployed on Trackprofiler today. The "Simplify track" option will remove points where the track resembles a straight line. You can still decide how many points to choose (by selecting "More points" or "Less points" on the page).

Note that by removing intermediate points you remove the metadata, too. Most importantly the time (needed to compute the speed) and elevation.  But, sometimes those are not that important and you need your tracks to contain only the shape of the path taken. If that's the case -- enjoy simplifying your tracks!

Happy new 2014

Happy new 2014 year!

As you can see from posts on this blog -- 2013 was a busy year for Trackprofiler. This year will probably see some more features. In the last few weeks I was compiling a list of features from users, and here it is. This is what you can expect this year:

• Simplify tracks by removing too many points.
• OpenStreetMap and Leaflet integration instead of Google Maps.
• Easier handling of multiple tracks (bulk rename, change tags, delete, ...).
• Support for the newer GPX version of: GPX 1.1 (and possibly more track formats, as well).
• Show multiple tracks on one page. 
• Multistep undo. At the moment the only way to revert an edit is to use "Revert to original track". With multistep undo You'll be able to undo only single edits.
• Login with Mozilla persona.
• Better editing tools for tags, automatic detection of tags.
• Share waypoints between multiple tracks.
• Public Trackprofiler API.
• Bulk download of tracks on Dropbox.
• User-defined colors for track segments.
• Microsites (more on this later...).

In italic are the features planned for the first 3-4 months of this year.

This is not a definitive list, maybe some new and important features will be added, but I hope that at least two-thirds of this list will be ready this year.

Split and move GPS track segments

Some GPS devices record tracks with random errors like this:

I followed a smooth path here, the actual GPS track looks pretty irregular. To fix it you need to move every point, or just use a real GPS (instead of a smartphone "GPS" :-).

Other times your track may look something like this:

Note that the first part of the track follows the road but then it "decides" to leave the road (in reality, I never went off-road there) and then, later, it returns back on the road. To fix a problem like this one until now you had to use the "Edit points" option and move points one by one.

This is a problem people from CadenceVR had. For their product (a virtual reality cycling/training application), they need to have reliable tracks files. But when the GPS make an error like the above -- they need to fix many (thousands!) points by moving them one by one, and every move by the same few meters in the same direction.

After a few days of emailing back and forth with ideas on how to fix problems like this one, a new feature of Trackprofiler is born. You can now use the Segment editor to split segments and move them around:



How to do it...

• Click on the track to split the segment into two new (you can merge them back later)
• Drag the marker with the number at the start of the segment. The entire segment will move accordingly. 
• When the segment is moved where it should have been you can merge the segments again.

Track segment editor

Let's suppose you recorded a track like this:



Note that the path is "broken" in 4 smaller parts. Those parts are called track segments. Every track can have multiple track segments and GPS devices will usually create a new segment every time it lost GPS satellite visibility (for example if you entered in a tunnel or  a deep canyon) or you temporarily switched it off.

But we have another problem here. When we reached the peak the batteries of our GPS discharged and that's why we don't have the return of our trip recorded. BTW, the return was the same path.

This is a typical scenario where you would use the new "Track segment editor" on Trackprofiler. When you click on the "segment editor" tab you will see the map with numbered segments and on the right the list with all possible operations on single segments:

By selecting the drop-down with the number you can change the segment order in your GPS file. Use  to reverse the order of points inside that segment. With  you can duplicate the segment or delete it with .

Use  to join two segments.

Now back to our problematic track. We need to:

• Join all our segments using ,
• copy the resulting segment with ,
• reverse the points on the second segment (the returning path) with ,
• join them together with .

...and the result will be the complete path without "holes":

The Track segment editor is online now. 

Feedback is welcome!

Geoelevations for Ruby

WGS84 Undulations map of the Earth

Just released another open source project related to Trackprofiler. Geoelevations.rb is a SRTM and EGM2008 undulations parser library for Ruby:

Geoelevations.rb is a SRTM and EGM2008 undulations parser library for ruby. Geoelevation.rb allows you to retrieve the elevation for any point in Earth (if present in the SRTM dataset) and the Geoid undulation (the difference between the WGS84 ellipsoid and the actual Earth size). 

SRTM: "The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth." 

EGM2008: "The official Earth Gravitational Model EGM2008". Part of this dataset is a "geoid undulation values with respect to WGS 84".

Basically it is simillar to the existing Python SRTM library (used in Trackprofiler to add elevations to GPS tracks) with two differences:

• It is written in Ruby,
• It contains also a EGM2008 undulations data (remember the difference between smartphone elevation and the actual elevation? That's the reason).

Geoelevations.rb is hosted here: github.com/tkrajina/geoelevations