FREQUENTLY ASKED QUESTIONS

How 3D informations are obtained ?

All paths geometries are “draped” on a Digital Elevation Model, when created or updated.

All linear objects that defined using topologies (treks, …) take their 3D informations from their related paths, instead of reading the DEM.

How the ascent is computed on treks ?

We compute the cumulative elevation gain.

We sample the DEM every 25m by defaut (see ALTIMETRIC_PROFILE_PRECISION setting), and we add some smoothing to avoid noise.

For more details :

• The smoothing explanation

• The piece of code to compute positive and negative accumulations

• Draping lines with PostGIS (or french version)

How POIs are related to treks ?

POIs are considered as an editorial information, and are created carefully along treks.

When a POI is created, it is attached to the closest path.

A trek is defined by a serie of paths, and some POIs are associated to them.

Note

There is currently no way to manually control the association between treks and POIs.

This was discussed among the first Geotrek users, come and argue on the mailing list !

If TREKKING_TOPOLOGY_ENABLED is set to False, there are no paths involved. POIs are thus related to treks using a basic spatial intersection, with a distance set in setting TREK_POI_INTERSECTION_MARGIN (default to 500 meters).

Can I have overlapping districts ?

Districts are a generic notion to qualify your territory. They can be valleys, mounts, …

You can imagine using the districts table for all those different notions, resulting in overlapping geometries. Geotrek-admin will associate them all to your objects.

Why Makina Corpus sells Geotrek, released under an Open-Source license ?

In the early years of the Free Software movement, it was quite common to pay in order to receive a physical copy (on floppy disks) of some GNU programs and source code.

In the late nineties, the IT industry was not confortable with the confusion introduced by the word Free in English (“free” as freedom, or “free” as costless), and therefore started to spread the word Open Source instead.

Today, those copies of Open Source software can be obtained on the Internet for free of course. But yet, the GNU Software Fundation still recommends to claim a financial contribution when distributing them, in order to support the development and maintenance. And note that nowadays, many of the most important Open Source applications have their own fundation, focused on collecting funds for development and maintenance.

The Geotrek fundation does not exist yet, but the community is growing. Makina Corpus is currently maintaining this Open Source application, which implies the following responsabilities :

• Maintain a public website, with a fully working demo ;

• Write documentation ;

• Provide community support on the mailing-list ;

• Promote the application at conferences, social networks and communities ;

• Triage and investigate issues tickets on Github ;

• Fix bugs and regressions if any ;

• Contribute, propose and argue code merge on external libraries ;

• Keep software dependencies up-to-date, without regressions ;

• Make sure the application remains easy to install on latest Linux distributions ;

• Add some engineering to allow customization and pluggability when new specific features are planned ;

Each of these tasks are often considered implicit, but they consume energy and time, which represents a substantial cost for a company like ours.

To conclude, we don’t really sell Geotrek, since you can get it on Github and install it easily, but we ask for a financial contribution regarding the above responsabilities. It is not only legal, but also recommended by the funders of the Free and Open Source Software movement.

How can I help and contribute ?

There are many ways to contribute to a Free Software. And modifying the source code is probably the least common action. For example :

• Help the users and answers questions on the mailing-list ;

• Download it, try it ;

• Open a ticket when you encounter a bug ;

• Open a ticket when you have a suggestion or feature idea ;

• Share your feedback, spread the word inside your organization ;

• Write and talk about Geotrek, at conferences, workgroups, forums ;

• Translate the documentation ;

• Translate the menus, buttons and labels (we use Weblate) ;

• Maintain the installation script for different Linux distributions (requires some basic Linux skills) ;

• Fix bugs or improve layout and apparence (requires Webmaster skills) ;

• Fix bugs or improve core modules (requires python/Django skills).

Join us on the mailing-list! Send an email to geotrek-fr+subscribe@googlegroups.com and you will receive an invitation automatically :)