The bordermarkers of the Pyrenees : gps and cartography

I'm using a gps-device since 2006 to measure bordermarker-coordinates and to record tracks.  Online mapping-services like Google Earth and Geoportail are increasingly accurate and useful.

It's my intent to provide tracks, waypoints and ultimately the GRPdesBF-trail appearing as exact as possible within Google Earth.  So the main medium will be the .kml-format. But there will be conversions in the more universal .gpx-format which can be imported on gps-devices and map-sites.

Print your own maps
It's easy to print your own - custom made - maps with the GRPdesBF-route and the bordermarkers on them.
See: this page

All bordermarker-coordinates in 1 gps-file
Two flavours:
- Google Earth-kml: esfr-bordermarkers-all-waypoints.kml
- Gpx-file: esfr-bordermarkers-all-waypoints.gpx
(with altitudes added from the NASA SRTM3 database)

The coordinates in this file can differ from the coordinates in the individual daytrip-tracks. In those cases, this is the authoritative list, showing the locations as exact as I can get them. Most of them are based on my own gps-readings and are corrected to show as exact as possible within Google Earth. A minority is derived from the French IGN-maps or from other sources.

Tracks of the trips
The kml-tracks of the daytrips and ultimately the GRPdesBF are drawn on Google Earths-maps. If gps-tracks (recorded while walking) were available, they were usually corrected to 'fit' as exact as possible on the roads and trails visible in GE.

Measuring the altitudes of waypoints and tracks
Altitudes recorded by gps-devices are not quite reliable or consistent. I've chosen to  use existant altitude databases and the most precise and free data - for Europe - was until september 2014 the NASA SRTM3 database. More information on SRTM on this page.
So: the .kml-files (containing no elevation data) are converted into .gpx-files with the elevation data from the SRTM-database added. That should produce more consistent altitudes of waypoints and tracks then by own gps-recording. However: the NASA SRTM3 data have a resolution of ± 90x90m (outside the USA) which implicates an inaccuracy when producing an elevation profile of a track.
The gpsvisualizer-site provides an option to add altitudes from the SRTM3-database to an existing gps-track. But that doesn't work flawlessly: in some cases gaps of zero altitudes appear in the track or the cumulative elevations are unexplainably high.

So I shifted in august 2014 to the GPS-Track-Analyse.NET-program. This - german-language - software does the job more reliable using downloaded elevation data. So you can use your own choice of DEM-databases. For example the corrected NASA-databases on Digital Elevation Data. GPS-Track-Analyse has a direct export link to the Basecamp-program to do the final measuring of distances and elevations.
Addition may 2015: the NASA has now released SRTM1-data (resolution 30x30m) for the rest of the world. See this webpage. How to download them? See this page. But then you end up with files in either the Geotiff, Dted or Bil-format. But the above mentioned program GPS-Track-Analyse.Net can only read the .hgt-format. But there's a solution: the androïd app DEM1 is able to download SRTM1-data in hgt-format. I did that for the Pyrenees and from may 2015 I will use these precise altitude data for new measurements.

How exact is Google Earth calibrated?
Well, I'm not an expert on gps, GE or mapping but we can all see that the images on Google Earth can be astonishing detailed. Often we can distinguish the bordermarkers themselves.  But how exact is the alignment of the images with the real coordinates of cartographic objects? Well pretty exact in my experience if the terrrain is flat. However, in the mountains with steep slopes and narrow ridges the difference can be noticeable.
For example: the historical modus of GE - showing earlier satellite-pictures - gives sometimes a slight change of the bm-location over the years. One would assume that the most recent satellite-maps are the best calibrated ones. But that is not always the case. However, remember that - when projected on a 25k topographical map - these differences are usually irrelevant.

How exact is your gps-device?
Recorded waypoints and tracks can be amazingly exact within GE.  But remember that a gps-reading in the best circumstances still can differ up to 5 meters from the actual coordinates.  In dense forests the difference can be much more, even moren on wooded slopes. Professional land surveyors have gps-devices which can use additional information from broadcast stations producing exact coordinates.

Cartographic Sites/Software
Allmost all maps and tracks on this site are made or derived with/from online services.

Google Earth:
Amazingly detailed satellite maps, including a 3D modus.  Making tracks and waypoints is easy in the .kml-format. Note: if you want to import .gpx-files, GE removes details of the track. It's better to load the .gpx first in Garmin's Mapsource or Campbase and from there show it in GE.
Although the maps are very detailed, the satellite maps of Windows Live Maps (Bing maps nowadays) can be even more sharp or reveal details which are in shadow on GE.
Within GE you can easily switch between both with:

Map overlays for Google Earth
This  site gives the opportunity to project in Google Earth other map-images from Google, Yahoo, Windows Live and Open Street maps.  Besides the very detailed Windows Live satellite maps, I especially like the terrain-view of Google Maps which shows the elevation lines.
There are more overlay-combinations like this one, e.g.
I selected the most useful for our purposes in Eefs Overlays

Great site to convert gps-files and to draw maps on many maps. Has the ability of adding elevation-data to your gps-files.

Google Maps:
Provides street maps, terrain-maps and recently incorporated Google Earth in its map-choices.  You can paste internet-links to .gpx and .kml-files in the search-frame but not load them from your pc.

From this site, you can download an extensive and free hikingmap of the Pyrenees. It can only be used in Garmin-software (Mapsource / Basecamp) and on Garmin-gps-devices.
(Installing this map-software wasn’t that straightforward (at my computer): in the download-process the two files were renamed and that prevented a proper ‘unzipping’. So: when you have downloaded both files, check of they have the following names: ‘TOPO PIRINEOS 6.1.part1.rar’ and ‘TOPO PIRINEOS 6.1.part2.rar’ (of course without the ‘). If not, rename them. Finally you can ‘unzip’ them with software like Winrar of 7-zip. The unzipping gives a giant .exe-file which does the final installment. In Mapsource or Basecamp you can choose this map as map-layer.)
And what does this map offer? Well, every bordermarker is indicated (pillar or cross), the coordinates being provided by Charles Darrieu and Paco Nudels but most of all we see many, many trails which we don’t see on the official maps. You can distinguish between official waymarked trails (and see their names) and other trails. It’s a treasury! But remember: not all trails seem established trails, a few look like personal trials.

This - german-language - software can add altitudes to gps-tracks using downloaded elevation data (DEM).  It has a direct export link to the Garmin Basecamp-program to do the final measuring of distances and elevations in that program.

Digital Elevation Data
Great site about 'DEM'-s = Digital Elevation Models. These are databases of the altitudes on a map. This website offers corrected versions of - among others - the official NASA SRTM3 DEM's. These can be used in for example the above mentioned program GPS-Track-Analyse.NET. But SRTM3-data are not very precise (90x90m).

An Androïd app which does one job: downloading SRTM1-data which have become available for Europe since the end of 2014. These SRTM1-data are in the .hgt-format and that's the only DEM-format which the above mentioned program GPS-Track-Analyse.NET can use.

Using smartphones and tablets
Smartphones and tablets with their in-built gps-receivers can be very useful for our purpose: wayfinding and locating bordermarkers. But you will need appropiate software-applications ('apps').  And remember: their battery capacity is usually limited and might be insufficient to cover a whole day of walking. My requirements for the software (apps):

- offering (or being able to handle) off-line maps on a topographic scale
- being able to store these maps on the external sd-card (they can be very large)
- capable of loading gps-tracks and waypoint-files (for example my gpx-file with all bordermarker-waypoints of the Pyrenees)
- being able to make your own waypoints
- being able to record your tracks

I tried several apps on my (Android) smartphone and tablet. These ones fit the above requirements:

Osmand: amazing app which uses OSM-maps. Open Source Maps is a volunteers-project like Wikipedia and the maps can be very detailed depending on how active the volunteers are in the region in question. There's the (paid) option to add elevation-lines. Highly recommendable

Oruxmaps: a similar app being able to use OSM-maps but also other formats like the Oziexplorer ozf2-format and Garmin vectorial maps like Topopirineos. This is potentially the most powerful app but is also more complicated to use.

French online cartographic services

Conseil national de l'information géographique
This page on the border of France with Spain shows several links:
- to an online map which shows the official borderline including existing differences of opinion on the exact borderline
- two very interesting documents with the proceedings and annexes of the 40ème Réunion de la commission internationale des Pyrénées - Paris, 03 décembre 2014
- a link (I'm proud) to my website

A elaborate French mapping site, a sort of mix of Google Maps and Google Earth but focused on France. Since 2010 you can import .gpx-files and .kml-files. Geoportail has in its principal viewer a wealth of information divided in layers, uses other satellite maps and provides among others cadastral maps.

Visugpx draws maps of .gpx-files in two formats: one is in a Googlemaps-frame (which can be done by many more sites) and the other one is on the French IGN-topographical maps which is more unique and very useful. You can enlarge the viewframe ("Afficher en grande taille") and details are given about lenght, elevation profile and so on. If Visugpx doesn't perform properly, you might try another internet-browser like Firefox or Chrome.

Spanish online cartographic services

Nationwide there are two possibilities:
1. The Iberpix-viewer of the IGN: you can zoom-in to 25k-level, showing a remarkable relief-shading on the maps, showing overlap with France and even bordermarkers. The satellite images are very detailed and you can import .gpx-files.
2. The Sigpac-viewer which uses the same maps as Iberpix at 25k-level but you can't load gps-files

Each Spanish province has in addition its own service, each one different. They have one disadvantage in common (except Sitna): they don't show the bordermarkers. But they can be useful to check the borderline in some special cases.  If they don't perform well in your browser, try another one, e.g. Opera.

GeoEuskadi viewer
Covers the small Baskian portion of the esfr-border

The 'Geoportal' of Navarra offers this viewer which allows to zoom-in very deep. In the 'topographic cartograpy'-mode you'll see the bordermarkers indicated ("muga") if you zoom-in enough.

The service of Aragon.

Catalonia has the largest stretch of the esfr-border. Its Cartographic Institute provides a nice viewer of its topographic maps. It has a large zoom-in capability - with very detailed elevation lines - and offers satellite pictures as well. You can import .kml and .gpx-files. An unique and very useful feature: an overlay-function within Google Earth: see this page and choose Google Earth -> Automatic (tile)

Andorran online cartographic services
The Andorran government offers various maps for download on this page. For our purpose (a trail through Andorra from Port de Rat to the Portella Blanca), three series are relevant: fourteen 10k-maps with walking trails indicated a 50k overview-map of Andorra 5k maps, unfortunately not covering all Andorra