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Benchmark Hunting in France

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Hello,

My name is Gerard (aka gperlier) and I'm French.

I'm really interesting in Benchmark Hunting unfortunately only available in US.

In France there is a database comparable to the NGS one, called IGN (Institut Geographique National) with a web site http://geodesie.ign.fr/

Do you think possible to extend the geocaching database with manual inputs?

In example:

- Details for Benchmark: BMF0000001

- N 49° 38.116 E 005° 38.850 (RGF93)

- Designation: ETAIN II BORNE GRANIT

- Original datasheet: http://geodesie.ign.fr/fiche_geodesie.asp?...0&Y=2474100

Thanks for your answers.

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Hi Gerard -

 

The benchmark hunting database that Groundspeak obtained from the U.S. government is not expandable - it is a static database.

 

However Groundspeak also made the Waymarking site and there is a section of it for benchmarks. They also made Waymarking to have a feature where members could make new categories in a process themselves. There are already benchmark categories for UK&Ireland, Canada, U.S., Spain, Australia, and Portugal. Although there is one for Europe in general, I encourage you to make one for France. :D If you need any assitance with making a waymark category for benchmarks in France, send me a message.

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I could be a third body to help get the category up and running.

 

I will officer up for you as well.

 

I have several other countries I am involved with their benchmarks and survey stones at Waymarking.

Another would not hurt.

 

Maybe you could be a part of the GEOCAC benchmark for France.

I have heard that there may be a way for us to get it done.

E-mail me if you are interested in trying.

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If you need someone who speaks reasonable French, let me know.

-Paul

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If you need someone who speaks reasonable French, let me know.

-Paul

 

If the OP creates a category for French benchmarks you would be a great addition to his category.

 

I don't even speak unreasonable French so my offer of a warm body is all that I can offer. :)

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Many thanks for your answers!!!

Our intend, Karolos and I, was to propose Mark.gif to the French Geocaching.com community, as I did with Earth.gif, Event.gif, Letter.gif, Wherigo.gif !!!

You said this not possible due to the NGS static database so I’ll initiate a new Waymark category called “French Benchmarks”.

I sent you all an invitation to join the “French Waymarkers” group to benefit of your experience…

Gerard

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- Details for Benchmark: BMF0000001

- N 49° 38.116 E 005° 38.850 (RGF93)

- Designation: ETAIN II BORNE GRANIT

- Original datasheet: http://geodesie.ign.fr/fiche_geodesie.asp?...0&Y=2474100

This appears to be an intersection station. I appreciate the excellent diagrams and other picture-is-worth-1,000-words finding aids. Thanks for showing us this.

 

-ArtMan-

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Hello,

I just sent the new category "French Benchmarks" to French Officers approval (Sorry but it's in French)!!!

 

"Description:

La Géodésie est la science de la forme et de la dimension de la Terre. Le Système Géodésique Français

 

Expanded Description:

Afin de localiser un objet sur la Terre il faut définir un Système Géodésique.

En France, il a donc été créé un Réseau Géodésique physiquement lié à la croute terrestre (borne, pilier, plaque, repère, etc…) dont les coordonnées et/ou l’altitude sont connues avec précision.

 

La Nouvelle Triangulation Française (NTF) est matérialisée sur le terrain par:

- 800 points de 1er Ordre espacés d’environ 30km,

- 5 000 points de 2eme Ordre espacés d’environ 10km,

- 60 000 points de 3eme et 4eme Ordre espacés d’environ 3km,

- 20 000 points complémentaires de 5eme et 6eme Ordre (moins précis)

 

Le Réseau Géodésique Français (RGF) est le successeur de la Nouvelle Triangulation de la France (NTF).

C'est la réalisation nationale d'un système de référence tridimensionnel mondial, de précision centimétrique, adapté aux technologies modernes de positionnement.

Il est composé de:

- 23 points du Réseau de Référence Français (RRF déterminés par Géodésie)

- 1 009 sites du Réseau de Base de la France (RBF déterminé par GPS))

 

Le réseau de Nivellement Général de la France (NGF):

Il a nécessité l'observation et le calcul de plus de 450 000 repères, généralement placés sur des ’’points durs’’ tels que ponts, soubassements de bâtiments, à environ un mètre du sol.

Tous ont (ou ont eu) une plaque indiquant l'altitude du lieu. Leur forme permet de s'en servir comme appui pour y poser une mire de Géomètre.

 

Tout ces points sont référencés par l’Institut Géographique National (IGN) et font tous l’objet d’une fiche individuelle les décrivant.

 

Vous trouverez facilement ces fiches sur geodesie.ign.fr ou sur geoportail.fr

 

Infos issues de © IGN.fr"

 

Regards,

Gérard

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I have several other countries I am involved with their benchmarks and survey stones at Waymarking.

I have heard that there may be a way for us to get it done.

Hello Charles,

All IGN sheets are available trough 2 FTP databases:

- Geodetic

- Cadastral

Do you think possible to have these more than 536.800 sheets included into the "NGS" Geocaching database, in order to offer Benchmark caches Mark.gif in France???

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gperlier -

 

The French benchmark category description is excellent !

(I had help from http://babelfish.yahoo.com/ ;) )

 

I have only 2 comments:

 

1. There might be some benchmarks that are not included in ces fiches sur geodesie.ign.fr ou sur geoportail.fr. Could they be waymarked in this category too, if any are found? Here in the U.S., there are many towns that have their own benchmarks that are often not included in the national database, yet we allow Waymarking them.

 

2. The optional view from a few meters should include the idea that the point should be visibile in the sight.

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It looks to me as if Gerard is asking whether the different sets of French BM descriptions could just be added to the Geocaching.com database, as a sort of a "sidecar".

 

To my amateur eye, the sets of descriptions are quite different (just looking at the cadastral set for France). Someone would have to come up with a database structure for each set of French data, come up with coded input data, load up the actual sheets (which could then be printed out), and then do a "one-time upload" similar to the one I believe was done in 2002 for the Geocaching.com NGS data. Quite an undertaking, assuming that the owners of Geocaching.com were even agreeable to "adding-on" the French data.

 

Judging from the French cadastral dataset, the French marks seem to be quite near major roadways, which are key to their descriptions, reported in Lambert coordinates (which I gather are easily convertible into Lat/Long.

The mapping interfaces available for the US marks would not be available, and the various "tracking" features of the website would not work straightforwardly for the French marks. But it would be a neat (if gigantic) project.

 

I volunteer for an all-expense paid trip to France to reconnoiter a sample of French marks in great detail as necessary. A time-frame around the French wine harvest (Sept-Oct) would seem a good bet.

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Do you think possible to have these more than 536.800 sheets included into the "NGS" Geocaching database, in order to offer Benchmark caches Mark.gif in France???

I don't think that Groundspeak will be including the 536,000 datasheets in to the "NGS" Geocaching database. We know about several U.S. datasheet sites (listed in Zhanna's site) that have benchmarks that are not in the NGS database and the Canada Benchmarks waymark site references some large Canadian benchmark databases and Groundspeak has not imported those either.

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Just back from a couple of weeks in France filled with visiting some folks, playing tourist, and maybe a bit of eating and drinking, as well. Also, I slipped in a little casual benchmarking.

 

The French equivalent of NGS, known as IGN, publishes benchmark datasheets online. The site is in French only. Google Chrome does an adequate job of translation, though if you know a bit of French, it obviously helps.

 

Starting on the Benchmark page, click on the map on the right side of the page. It works pretty much like other GIS applications you've probably used. Zoom in on the area of interest, (use the "+" control), then select the point of interest (the "I" control, as in upper case eye, for information). Download the PDF.

 

The datasheet has a map and photo, but otherwise has much less description than is typical of NGS datasheets.

 

One mark I recovered was in Cancale, a town on the north coast of Brittany famed for its oysters. Justly famed, I can attest. Mmmm. But this mark was a mile or so from the port, where freshly-harvested oysters are on offer. It — the benchmark, not the oyster sellers — looks like this.

 

2012-09-23_2992_benchmark900px.jpg?t=1348868941

 

The elevation is stamped on the mark plus/minus one meter, but the datasheet gives it as "52,583 m;" note the continental practice of using a comma where we use a dot.

 

Anyway, here's the area photo, showing the benchmark at about knee-high on the cemetery wall. I believe the datue point leveled to is the top of the red frame.

 

2012-09-23_2994_benchmark900px.jpg?t=1348868941

 

The line near the top of the datasheet, "Repère vu en place en 2012," indicates it was last seen in place this year. But otherwise the datasheet does not include the kind of recovery reports that many of us contribute to the NGS.

 

à votre service,

ArtMan

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ArtMan,

 

Thanks for your story and pictures about French benchmarks! It is fascinating to see benchmarks from other nations and to see where they are set. Now we are more prepared for the next time we visit France...

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