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EurAlpGM2011 220m resolution Gravity Model for the Alps - readme-file V1.0
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Contact: Christian Hirt 
Western Australian Centre for Geodesy
Curtin University Perth
c.hirt(use the at here)curtin.edu.au &
c.hirt(use the at here)tum.de

Last edited 2015-03-26

1. SUMMARY
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EurAlpGM2011 is a high-resolution description of the gravity field over the 
European Alps. It is constructed as composite model using EGM2008 in spectral 
band of spherical harmonic degrees 2 to 2190 and topography-implied gravity 
effects from residual terrain model data beyond harmonic degree 2190. The 
innovation of EurAlpGM2011 lies in the use of a new approach for the evaluation 
of EGM2008 gravity functionals at densely-spaced points at the Earth's 
topography, as represented through the SRTM elevation model. For a detailed 
description see Hirt (2012). EurAlpGM2011 was released in 2012.

EurAlpGM2011 was a case study for the development of the GGMplus
global gravity maps (http://ddfe.curtin.edu.au/models/GGMplus). 

Citation:
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Hirt, C. (2012), Efficient and accurate high-degree spherical harmonic synthesis 
of gravity field functionals at the Earth's surface using the gradient approach. 
Journal of Geodesy, 86(9), 729-744, DOI: 10.1007/s00190-012-0550-y.


Permanent link to the EurAlpGM2011 data sets 
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http://ddfe.curtin.edu.au/models/EurAlpGM2011/            


2. INPUT DATA AND PROCESSING
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is described at geodesy.curtin.edu.au/research/models/EurAlpGM2011/
and at http://ddfe.curtin.edu.au/models/EURALPGM2011/EurAlpGM2011_website.pdf
and at http://ddfe.curtin.edu.au/models/EURALPGM2011/hirt2012_efficientSHS.pdf


3. EURALPGM2011 ARCHIVED PRODUCTS
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are organized in following directories

/data      .. contains 15 220-m resolution grids of EurAlpGM2011 
              functionals and input data sets  
                               
/images    .. contains high-resolution images from the EurAlpGM2011 websites

/software  .. contains a Matlab script to read the EurAlpGM2011 binary grids



4. FORMAT DESCRIPTION
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Each data file contains 2,000 x 6,000 =12,000,000 values. The grid resolution 
is 0.002 degree (7.2 arc seconds) with the grid equally spaced in terms of 
geodetic  (GRS80) latitude and longitude. The area covered is
44.001 to 47.999 degree geodetic latitude,
5.001 to 16.999 degree geodetic longitude.
Records proceed along meridians from South to North and columns proceed from 
West to East. The first record is the South-West corner (44.001 deg latitude, 
5.001 deg longitude), and the last record is the North-East corner (47.999 deg 
latitude, 16.999 deg longitude). Depending on the dynamic range of each file, 
data is stored either in 2-byte integer big-endian format (int16, ieee-be), or 
4-byte big-endian format (int32, ieee-be), whereby the file's storage format 
is included in the assigned filenames. The file sizes are 23.4 MB for int16 
and 46.9 MB for int32 formats.

REFERENCES
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are given in Hirt (2012).

DISCLAIMER
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Neither Curtin University nor any of its staff accept any liability in 
connection with the use of data and models provided here. Neither Curtin 
University nor any of its staff make any warranty of fitness, completeness, 
usefulness and accuracy of the data and models for any intended or unintended 
purpose.