a project for archiving and managing physical geodesy data in antarctica capra a. and gandolfi s....

A Project for archiving and managing A Project for archiving and managing physical geodesy data in Antarcticaphysical geodesy data in Antarctica

Capra A. and Gandolfi S.

DISTART - University of Bologna

Viale Risorgimento n°2 - 40136 - Bologna

Alessandro.Capra@mail.ing.unibo.it

Stefano.Gandolfi@mail.ing.unibo.it

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Study of collecting and managing Physical Geodesy Data for the computation of Local and Regional Geoid in Antarctica.

It will be obtained starting from a global model of geoid and corrected by the use of geodetic, gravimetric measurements and density model.

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FirstFirst StepStep

Archiving data from different researchers and countries, obtained with different methodologies. Data could be provided in different reference frames.

The collection should be transformed in the same DATUM in order to perform an homogeneous datasheet

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Essential data input for geoid computation in Antarctica:

•Geodesy (Classical, SAR, Sat. Altimetry, GPS, Tide Gauge)

•Bathymetry

•Gravimetry

•Radar Echo Sounding (RES)

•Global geoid model (EGM ??, OSU ??)Note: Till today the only available Geoid Map of Antarctica was made by AUSLIG in 1990, based on Geopotential Coefficient set OSU89A

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In Antarctica the ice-thickness is changing relatively quickly for many reason (ice movement and ice melting principally), so the ice topography should be computed periodically. Regarding this point a closed data exchange should be made with BEDMAP (Bedrock Map Antarctica Project) and RAMP (Radarsat Mapping Working Group).

It is necessary to study a Data Base Management System for geodetic and gravimetric measurements. This DBMS could allow an easier archiving of so different data in term of acquisition and precision. Moreover could allow a correct data analysis to establish the level of desired accuracy.

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DBMS for geodetic Measurements in Antarctica requires for some particularity with respect to other kind of DBMS for Geodesy.

1) The atmospheric, climatic and morphologic condition don’t permit the easier development of classical measurements, especially in the inner part of Antarctica Continent.

2) Space geodesy will constitute the greater part of DBMS

3) Despite of the above consideration, some classical observation will be considered in particular in region close to tide gauges.

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DBMS - For Geodetic Measurements in Antarctica

Typology of data considered:

a) GPS data (Static - DGPS - Kinematic)b) DORISc) SARd) Satellite Altimetryd) Tide Gaugee) Some Classical Survey

Typology of data generally not available:

a) Spirit Levellingb) SLRc) VLBI

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DBMS - For Geodetic Measurements in Antarctica

Each datasheet must be coupled with a Form (Main Form + Sub Form) as Identity Card of the Survey.

In the Main Form will be appear some information on Company, Year, Reference, Name of Survey, Location or Region and for each kind of survey a particular “Sub Form” permit to better understand modality, instrumentation, software, reference frame and every kind of information relative to the datasheet.

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F o rm 1

In p u t 1

S u b F orm

D a ta sh eet 1

F o rm n

In p u t n

S u b F orm

D a ta sh eet n

Tra n sfo rm a tio n P a ra m etersD a tu m

E llip so id.................

Tra n sfo rm a tio n o rC o m p u ta tion

R eg u la r G ridC o n to u r

M a p

D ataA n a ly sis

...............

DBMS - For Geodetic Measurements in Antarctica

M o d ified fo rm sW ith e lem en ts o f th e n ew tra n sform atio na n d e lem en ts o f th efir st fo rm . It w ill b e p o ssib le to h a v e a IDto search on th e m ainD a ta se t.

H om o g en eou sd a ta set w ith ID o f th e re la tiv e m od ifiedfo rm

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DBMS - For Geodetic Measurements in Antarctica

Example of a Main Form

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DBMS - For Geodetic Measurements in Antarctica

Example of a Main Form: Location of the SurveyThe possibility to classify each survey with a associated label of the region where the survey has been performed, allows a faster selection for local data integration and processing.

A criteria should be, for coastal region, the use of INDEX map of the 24 planned 1:1.000.000 scale coastal change and glaciological USGS Antarctica Maps, while for the inner part should be used the limits in longitude of each map tracked to the geographic pole. Another criteria should be obtained furnishing the quadrant and the sector. The sector is delimited in Longitude (10 degrees of amplitude) and in three strips: 60° - 70°, 70° - 80°, 80° - 90° of Latitude South.

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DBMS - For Geodetic Measurements in Antarctica

Example of a Main Form: Location of the Survey:

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DBMS - For Geodetic Measurements in Antarctica

Example of a Sub Form for GPS Data

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DBMS - For Geodetic Measurements in Antarctica

Example of a Form for GPS Data input

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What’s DBMS for Gravimetry ?

Some consideration and property of DBMS for Geodesy were applied also for DBMS for Gravimetry.

The structure is still in progress but something is already prepared.

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F o rm n

In p u t n

D ata sh eet n

F o rm 1

In p u t 1

D ata sh eet 1

Tra n sfo rm atio n P a ra m etersD atu m

.................

Tra n sfo rm atio n o rR ed u ction

M o d ified fo rm sW ith e lem en ts o f th e n ew tra n sform a tiona n d e lem en ts o f th efir st fo rm . W ill b e p o ssib le to h a v e a IDto search o n th e m ainD ata se t.

H om o g en eou sd a ta set w ith ID of th e re la tiv e m o d ifiedfo rm

R eg u lar G ridC on to u r

M a p

D ataA n a ly sis

...............

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Example of The Main FormIUGG / IAG - July 1999IUGG / IAG - July 1999

Example of Data input by User

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Conclusion:

•In Antarctica the ice-thickness is changing relatively quickly for many reason so the ice topography should be computed periodically.

•It is necessary to study a Data Base Management System for geodetic and gravimetric measurements.

•Two DBMS (for Geodesy and for Gravimetry) could allow an easier archiving of so different data in term of acquisition and precision.

• The main structure of DBMS (especially for Geodesy) was performed.

•Now the DBMS for Geodesy and for Gravimetry are in progress.

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Next Steps:

The completion of the DBMS and the introduction of Physical Geodesy data for all the Researcher who want to collaborate.

It will be fundamental the data exchange with programs like BEDMAP, ADGRAV, RAMP etc..

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Bibliography

Knudsen T., Olesen A.O - A GIS based strategy for quality control of gravimetry IGS Bullettin N°8 Dec 1998, 85-92

Baiocchi V., Crespi M., Riguzzi F. - Mean density map for the Italian region by GIS tecnique. IGS Bullettin N°8 Dec 1998, 93-104

Pagiatakis S.D., Armenakis C. - Gravimetric geoind modelling with GIS. IGS Bullettin N°8 Dec 1998, 105-112

Biagi L., Brovelli M.A., Salemi G. - Geodetic data management with GIS and DBMS techniques. IGS Bullettin N°8 Dec 1998, 103-126.

Fotopoulos G., Kotsakis C., Sideris M. G. - Developments and evaluation of an New Canadian Geoid Model, Second joint Meeting of the Int. Gravity Commission and Int. Geoid Commission, Trieste, Sept. 7-12, 1998

Bell R. E., Small C., The development of a New Generation Gravity Map of Antarctica. Submitted to the Office of Polar Programs National Science Fundation.

And: http://www.nerc-bas.ac.uk/public/aedc/bedmap/ BEDMAP programhttp://polestar.mps.ohio-state.edu/amm_web/begin.htm Bird Polar researchhttp://ipmtf14.topo.polimi.it/~iges/ IGeShttp://www.scar-ggi.org.au/ SCAR