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Glossary

Definitions of terms used throughout this guide and in the builder UI.

APEx Geospatial Explorer

The end-user web map application that consumes the configuration produced by this builder. Often shortened to explorer or GE.

BIP / BSQ

Two pixel interleave layouts for multi-band raster files. BIP (Band Interleaved by Pixel) stores all bands for one pixel together — fast for spectral lookups at a point. BSQ (Band Sequential) stores one full band, then the next — fast for whole-band operations. The builder auto-detects the layout from a COG's IFDs and adjusts pixel-value extraction accordingly.

COG

Cloud Optimized GeoTIFF. A GeoTIFF organised into internal tiles and overviews so HTTP range requests can fetch the bytes needed for a given viewport without downloading the whole file. The preferred raster format for APEx layers.

Configuration / config

The JSON document this builder produces. Drives the explorer's services, layers, interface groups, charts, statistics, constraints, and layout.

CRS

Coordinate Reference System. Identifies how coordinates map to the Earth's surface — for example EPSG:3857 (Web Mercator) or EPSG:4326 (WGS 84 lat/lng). Used throughout the builder; we deliberately avoid the older term projection.

Data source

A reference to where layer data comes from — a COG URL, a WMS layer name, an S3 object, a CSV, etc. Distinct from a service: a service is the endpoint, a data source is one specific dataset on that endpoint.

FGB / FlatGeoBuf

A binary, streamable vector format with built-in spatial indexing. Like GeoJSON but faster and seekable over HTTP range requests.

Interface group

A user-facing grouping of layers in the explorer's sidebar. Configurable on the Layers tab. Activating an interface group toggles every layer it contains.

Sub-interface group

An optional second level of grouping inside an interface group. Used to build a three-level hierarchy in the explorer sidebar — see Sub-interface group hierarchy.

Layer

A renderable map item with a data source, styling, and metadata. Layers sit inside interface groups and are managed on the Layers tab.

Meta

The meta object in the configuration. Holds reusable definitions — projections, colormaps, categories, vector field schemas — that layers reference by name.

Plotly

The charting library that renders Charts in the explorer. Trace and layout settings configured in the Visual editor map directly to Plotly's trace/layout JSON.

Service

A reusable endpoint definition managed on the Services tab. Services play one of two roles today:

  • WMS / WMTS / WFS services are referenced live by layers — the chosen layer from the service is the data source, and editing the service URL re-points every layer that uses it.
  • STAC catalogues and S3 buckets act as discovery aids in the builder UI. The resolved direct URL of each picked asset is what is written into the config; the catalogue/bucket entry can be removed afterwards without breaking the layers built from it.

Support for referencing a STAC collection itself as a live data source (for example, to drive the temporal control with a time series) is planned for a future release.

STAC

SpatioTemporal Asset Catalog. A JSON specification for cataloguing geospatial assets. The builder browses STAC catalogues to find collections and items, then materialises selected assets as data sources.

Sub-interface group

See Interface group.

Viewer bundle

The compiled APEx Geospatial Explorer that the Preview tab embeds in an iframe. Versions are pinned per config so a config built against 3.5.0 keeps rendering against 3.5.0 even after newer bundles ship.

Zod

The runtime schema validation library used by useValidatedConfig and the JSON Config tab. Defines the canonical shape of every config field — see the JSON schema reference.