Update resources.md

docs/resources.md

@@ -101,6 +101,9 @@ Object Resource = {
 }
 ```
 
+Some resource generators do not support tiling (like `geodata-vector`). In that case tile and lod ranges
+can be omitted and `referenceFrames` becomes an array of reference frame IDs.
+
 ## URL templates
 
 This is documented elsewhere but as a convenience we provide URL template expansion documentation here.
@@ -287,6 +290,17 @@ part is used. This DEM can be accompanied with its geoid grid in the same way as
 By default all layers from the source dataset are served. Optionally, layer subset can be configured by providing list
 of layer names.
 
+Since there are not tiles generated by this generator the tile and lod ranges are ignored. To make resource
+configuration more readable we can omit them completely and use array of reference frame IDs for `referenceFrame`.
+For example:
+```javascript
+{
+    ...
+    referenceFrame = [ "melown2015", "earth-qsc" ],
+    ...
+```
+
+
 The Z-coordinate of all points from the original dataset undergoes heightcoding operation.
 
 ```javascript
@@ -365,6 +379,7 @@ Generates tiled geodata (`geodata-tiles` type) from pre-tiled data like MVT web
 Configuration is the same as for `geodata-vector` driver but input interpretation is different: option `definition.dataset` is:
  * for web services: a URL template that is expanded (see above) for each requested tile before opening and processing.
  * for MBTiles: a path to `.mbtiles` archive with appended template for tiles: `path/to/myvectors.mbtiles/{loclod}-{locx}-{locy}`
+Also, per-reference-frame tiling information is mandatory.
 
 Geodata's metatiles are generated purely from heightcoding GDAL dataset.