KHMD: Fixed 1-km Grid Quarterly Panels of Apartment Sales and Rentals in South Korea, 2011–2025

KHMD provides quarterly observation counts and reported price and rental distributions for apartment sales and leases in South Korea from 2011 to 2025, aggregated to a fixed 1-km grid. The selected input comprises 480 CSV files containing 20,916,100 observation occurrences. Of these, 20,403,079 were assigned to grid cells and 513,021 remained unassigned. The count panel contains 571,310 observed grid–quarter–transaction-family combinations. Quality summaries retain the input, assigned, and unassigned denominators. Repeated occurrences are preserved, and absent combinations are not filled with zeros. The project-defined grid, KHMD_UTMK_1KM_V1, uses EPSG:5179 with a 1,000-m spacing. Spatial assignments are referenced to 2026 cadastral data. Price summaries describe nominal reported values using exact type-7 quartiles, with cancellation-marked sale observations retained under the documented inclusion policy. The deposit provides grid–quarter aggregates, quality summaries, and provenance metadata, supported by the khmd R package for access and verification. Assignment rates describe the proportion of selected input observations assigned to grid cells. The accompanying documentation specifies the distributed files, the temporal scope of the cadastral reference, and the limits of spatial-linkage and source-coverage validation.