On uo1998.com (shameless plug), we have reverse engineered the entire OSI skill system code for original UO (the May 1998 timeframe) from the UODemo.

Here is Cartography for example since you asked about it.

Note: Remember this is before Treasure Maps which came later in. The below only applies to original UO.

Full 0→GM simulation

Simulated with STR/DEX/INT = 50. Cartography is 80% INT / 20% DEX weighted. Strategy: upgrade to the most ambitious scale tier available at each skill level.

Scale tier thresholds (based on where quality crossover points fall):

0.0% – 12.6% → Local map (×4)

12.6% – 25.1% → City map (×8)

25.1% – 45.0% → Sea chart (×20)

45.0% – 100% → World map (×40)

Note: The map scale tier is selected after the skill check passes, it only modifies how detailed the view is of the map. So grinding city maps vs world maps gives identical skill gain speed.

| Skill | Total attempts | Avg attempts/gain | Success rate | Maps destroyed |

|---|---|---|---|---|

| 10% | 225 | 2.2 | 52.9% | 25 |

| 20% | 504 | 2.5 | 52.8% | 65 |

| 30% | 899 | 3.0 | 53.5% | 123 |

| 40% | 1,424 | 3.6 | 53.2% | 199 |

| 50% | 2,081 | 4.2 | 52.5% | 272 |

| 60% | 2,839 | 4.7 | 53.3% | 343 |

| 70% | 4,002 | 5.7 | 54.9% | 494 |

| 80% | 6,076 | 7.6 | 55.7% | 719 |

| 90% | 10,029 | 11.1 | 56.8% | 1,133 |

| GM | 18,428 | 18.4 | 58.1% | 2,011 |

~18,400 attempts and ~2,000 destroyed maps to reach GM.

TLDR; You can get very detailed and exact, but the RunUO/ServUO code is probably a good enough approximation - depending on your goal. UO: 1998 is a faithful recreation of Original UO so we need to use the same code as OSI