Data analysis

• Levelling data
• GPS coordinates
• GPS / levelling height anomalies
• Statistics of the geoid comparisions

Levelling data

The submitted levelling data (geopotential differences or normal / orthometric heights) are checked and evaluated at the EUVN / UELN Data Centre in Leipzig Germany. The EUVN-DA markers, connected to a UELN benchmark are considered as part of UELN and they are involved in the subsequent UELN adjustments. Some countries provided only heights in their national height system, without direct UELN connections.Those submmissions were transformed into EVRF2007 using pre-defined transformation parameter sets.

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GPS coordinates

The quality of the ellipsoidal coordinates is under the responsibilty of the data providers. Within the project no dedicated GPS processing facility could be established. A rough quality assessment could be extracted from the campaign and processing details provided by the NMAs.

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GPS / levelling height anomalies

Beyond the internal data consistency check the most useful way is the comparison of the EUVN-DA height anomalies with the different European and local quasigeoid solutions. Using the ellipsoidal and levelled heights height anomalies are derived and compared against different gravimetric quasigeoid solutions and geopotential models. The European Gravity and Geoid Project (EGGP) has provided a series of continental quasigeoid solutions (EGG97, EGG03, EGG06, EGG07 and EGG08).

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Statistics of the geoid comparisions

The table shows the difference of the height anomalies derived from EUVN-DA solution and several European quasigeoid solutions in numerical form.

EUVN-DA - EGG97 comparison (click to enlarge)

EUVN-DA - EGG08 comparison (click to enlarge)

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