Deep guide to EPS: PDF's predecessor from Adobe, versions 1.2-3.0 since 1987, how to make an EPS map from OpenStreetMap for legacy print shops.
Excel XLSX (Office Open XML ISO 29500): POI tables with lat/lon, attribute exchange, OSM data export for non-GIS analysts.
Deep guide to DWG: Autodesk's binary AutoCAD format, 18 incompatible versions, ODA File Converter, honest OSM export workflow with DXF fallback.
DGN from Bentley MicroStation 1984: V7 vs V8 spec, ODA Teigha, AEC infrastructure pipeline, OSM object export to DGN.
COPC = LAZ 1.4 plus a built-in octree spatial index for streaming over HTTP. USGS 3DEP, AHN, forestry — the modern cloud standard for LiDAR.
CSV (RFC 4180) is the simplest tabular text format: lat/lon columns or WKT geometry, readable in Excel/pandas/R/QGIS; the open-data standard for POIs and addresses.
COG — the cloud-native GeoTIFF evolution: 512px internal tiles, overview pyramids, HTTP range requests, OGC standard since July 2023, OSM export via gdal_translate -of COG.
COLLADA is a Khronos XML format for 3D scene exchange: ISO/PAS 17506:2012, supports meshes/animation/physics, used by Google Earth, now being replaced by glTF.
CityJSON is a TU Delft JSON encoding of CityGML: 6-10× smaller than XML, v2.0 OGC Community Standard 2024, used by Dutch 3DBAG, Helsinki, Vienna.
CityGML is an OGC standard based on GML 3.2.1 for 3D city models: 5 detail levels (LOD0-LOD4), ADE extensions; used by Berlin, Helsinki, Munich, NYC.
Deep guide to CDR: CorelDRAW's proprietary format since 1989, RIFF and ZIP structures, and how OSM2CDR delivers a ready .cdr that opens with a double click.
Alembic from Lucasfilm and Sony 2010 (ASWF): Ogawa backend, baked-mesh cache for Maya/Houdini/RenderMan, OSM city export.