Auvergne Test
In 2004, the French Institut Géographique National (IGN), upon the request of the steering committee of the European Gravity and Geoid Project, prepared a dataset to test geoid computation methods and software. The Auvergne region, located in the centre of France, was selected as the target area. The dataset consists of about 240,000 gravity points, a digital terrestrial model and 75 GPS/levelling points, allowing for the computation and evaluation of a 3°×2° geoid is feasible.
Auvergne Dataset
Author: H. Duquenne, IGN/LAREG
Version: 4
Date: Jan 17, 2008
Levelled GPS points:
- File Name: GPS_LEV.PTS
- Contents: levelled GPS points from the “French Basic Network” and the so called “NIVAG” dataset. Number of points = 75.
- Geographic Limits: 45° ≤ ϕ ≤ 47°, 1.5° ≤ λ ≤ 4.5°
- Format: text ASCII
- Separator: space(s)
| Columns | Type of data | Data | Unit | Reference system |
| 1 - 9 | numeric, integer | identifier | ||
| 12 - 21 | numeric, float | latitude | decimal degree | RGF93/ETRS89 |
| 23 - 33 | numeric, float | longitude | decimal degree | RGF93/ETRS89 |
| 35 - 44 | numeric, float | normal height | metre | NGF-IGN69 |
| 46 - 54 | numeric, float | ellipsoidal height | metre | RGF93/ETRS89 |
- File Download: click here [4.1 KB]
Gravity points:
- File Name: GRAVI_V3.PTS
- Contents: gravity points from BGI database, with an evaluated accuracy of 0.25~0.75 mGal. Number of points = 244,009.
- Geographic Limits: 43° ≤ ϕ ≤ 49°, −1° ≤ λ ≤ 7°
- Format: text ASCII
- Separator: space(s)
| Columns | Type of data | Data | Unit | Reference system |
| 1 - 8 | numeric, integer | identifier | ||
| 10 - 20 | numeric, float | latitude | decimal degree | RGF93/ETRS89 |
| 22 - 32 | numeric, float | longitude | decimal degree | RGF93/ETRS89 |
| 34 - 41 | numeric, float | normal height | metre | NGF-IGN69 (Potsdam + 1930) |
| 43 - 50 | numeric, float | orthometric height | metre | NGF-IGN69 (IGSN71) |
| 52 - 59 | numeric, float | ellipsoidal height | metre | RGF93/ETRS89 |
| 61 - 70 | numeric, float | gravity | m/s**2 | IGSN71 |
| 72 - 79 | numeric, float | free-air gravity anomaly | mGal | IGSN71, GRS80, NGF-IGN69 |
- File Download: click here [18.8 MB]
Digital terrain model:
- File Name: H_MSL_CGIAR_V3.DTM
- Contents: digital terrain model (height above EGM96 geoid model) from SRTM USGS/NASA data.
- Geographic Limits: 42° ≤ ϕ ≤ 50°, − 2° ≤ λ ≤ 8°
- Format: text ASCII
- Separator: space(s)
- Header: 3 rows, 2 data per row
| Row 1: | min_latitude | max_latitude | (unit: decimal degree) |
| Row 2: | min_longitude | max_longitude | (unit: decimal degree) |
| Row 3: | latitude_spacing | longitude_spacing | (unit: decimal degree) |
- Body: heights, from North to South and, for each latitude, from West to East (longitude varies more quickly)
- Unit: metre
- Logical format: 9601 rows, 12001 columns
- Physical format: 9601 blocks of (1200 rows of 10 values + 1 row of 1 value + 1 empty row) values are numeric integer, coded with 5 digits separated by 1 space
- File Download: click here [144.0 MB]
- Declaration: The DTM "H_msl_cgiar_v3.dtm" has been built from SRTM USGS/NASA data processed by CIAT, version 3. Users are prohibited from any commercial, non-free resale, or redistribution without explicit written permission from CIAT. Users should acknowledge CIAT as the source used in the creation of any reports, publications, new data sets, derived products, or services resulting from the use of this data set. CIAT also request reprints of any publications and notification of any redistributing efforts. Users are kindly asked to cite this data in any published material produced using this data, and if possible link web pages to the CIAT SRTM website (http://srtm.csi.cgiar.org).
- Citation: A. Jarvis, H.I. Reuter, A. Nelson, E. Guevara (2006). Hole-filled seamless SRTM data V3. International Centre for Tropical Agriculture (CIAT), available from http://srtm.csi.cgiar.org.
Auvergne solutions
| Year | Name | Authors |
Institutions | Computation method | Status |
DOI |
| 2006 | QGAuvergne | H. Duquenne | IGN (France) |
Spherical FFT (GRAVSOFT) | PUBLIC | |
| 2017 | AuvGeoid2017-UNB | Janák et al. | STU-UNB (Slovakia-Canada) |
Standard UNB Stokes-Helmert's approach | PUBLIC | |
| 2019 | AuvGeoid2019-UNB-LS | Foroughi et al. | UNB-SUT-NTIS (Canada-Iran-Czech Republic) |
UNB Stokes-Helmert's approach | PUBLIC | |
| 2019 | AuvGeoid2019-OneStep | Goli et al. | SUT-UNB-NTIS (Iran-Canada-Czech Republic) |
One-step integration method | PUBLIC | |
| 2021 | Auvergne-ITUGRG2021 | Sakil et al. | ITU-GRG (Turkey) |
Least Squares Modification of Hotine's Integral with Additive Corrections | PUBLIC |
References
H. Duquenne (2006). A data set to test geoid computation methods. Proceedings of the 1st International Symposium of the International Gravity Field Service, Istanbul, Turkey, Harita Dergisi, pp. 61-65.
Bouron, P. (2004). Entretien du NGF avec assistance GPS (NIVAG) – Spécifications de produit. Technical report nr. IT 244, Service de Géodésie et Nivellement, Institut Géographique National (in French).
SGN (1996). Spécifications du Réseau de Base Français. Version 2.2. Technical report nr. IT 152, Service de Géodésie et Nivellement, Institut Géographique National (in French).
D. Toustou (1991). Chaîne de validation interactive de données gravimétriques: DIVA. Note technique n° 10, Bureau Gravimétrique International (in French).