Geoid versus quasigeoid: a case of physics versus geometry
Bibliographic record
Abstract
For decades now the geodetic community has been split down the middle overthe question as to whether geoid or quasigeoid should be used as a reference surface forheights. The choice of the geoid implies that orthometric heights must be considered, thechoice of the quasigeoid implies the use of the so-called normal heights. The problem withthe geoid, a physically meaningful surface, is that it is sensitive to the density variationswithin the Earth. The problem with the quasigeoid, which is not a physically meaningfulsurface, is that it requires integration over the Earth’s surface.Density variations that must be known for the geoid computation are those withintopography and these are becoming known with an increasing accuracy. On the otherhand, the surface of the Earth is not a surface over which we can integrate. Artificial“remedies” to this fatal problem exist but the effect of these remedies on the accuracy ofquasigeoid are not known. We argue that using a specific technique, known as Stokes-Helmert’s and using the increased knowledge of topographical density, the accuracy ofthe geoid can now be considered to be at least as good as the accuracy of the quasigeoid.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.028 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.004 | 0.040 |
| Scholarly communication | 0.007 | 0.023 |
| Open science | 0.002 | 0.006 |
| Research integrity | 0.006 | 0.009 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".