The
bordermarkers of the
Pyrenees : gps and
cartography
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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. 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)
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 other sources.
Tracks of the
trips
The
kml-tracks of the daytrips and ultimately the GRPdesBF are usually 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 (unless otherwise stated).
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 SRTM-data. More information on SRTM on this page.
So: the .kml-files
(containing no elevation data) are converted into .gpx-files with the
elevation data.
The gpsvisualizer-site
provides an option to add altitudes from the most precise SRTM-databases to an
existing gps-track. That should produce more
consistent altitudes
of waypoints and tracks then by own gps-recording.
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. http://ge-map-overlays.appspot.com/ I selected the most useful for our purposes in Eefs Overlays
Gpsvisualizer:
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.
Topopirineos
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.
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 present physical paths, they can be merely routes without a physical path or waymarks.
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 SRTM DEM's.
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, it's the one I use.
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
Geoportail
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.
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
Sitna
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.
Sitar
The service of Aragon.
ICC
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:
http://www.cartografia.ad/mapa-muntanyes-d-andorra: fourteen 10k-maps with walking trails indicated http://www.cartografia.ad/mapa-topografic-1-50-000: a 50k overview-map of Andorra
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