Troubleshooting & FAQ
Troubleshooting and FAQ
Explain missing resources, nullable geometry, code joins and browser cleanup.
Interpret missing results
| Result | Meaning and next step |
|---|---|
loadCountry / loadDivisions → null | No built-in resource for that code; check the corresponding code list. |
loadFeatures → null | No built-in layer for this map id. Keep the base map. |
countryByCode → undefined | The names table has no such code. |
focusRegionFit / regionCentre → null | The code is null or absent from this map. |
insetFor → null | The region has no inset; it is normally drawn in place. |
wrapIntoBox → null | This window shows no horizontally wrapped copy of the point. |
landAnchor / mainlandBounds → null | No outline ring exists to choose or frame. |
findQuestion → null | The target is unknown or explicitly unnamed. |
projectPoint / unprojectPoint → null | The projection cannot be reversed by these helpers. |
readMapData / readMapColors → null | Attribute input is absent or invalid according to its parser. |
A code or feature does not show
Check which canvas the code belongs to. JP selects Japan on the world; 13 selects Tokyo on Japan’s prefecture map. A feature layer must name the same map id. An unmatched layer is not reprojected onto another map. Map labels use available upstream names; an omitted Japanese reading is not a broken load.
Browser setup and cleanup
Create elements only in a browser, and wait for asynchronous data before reading loaded results. Handle native load/error events. Module mounts need a real HTMLElement and destroy() when removed. A resource import failure is an exception even though an unsupported code returns null. For images, include the style or supply the documented external style.