GeoShapes and the Asset Map

Owned by Andy Tseng
Mar 21, 2024
2 min read

Mediaflux can store specialised geographic metadata (latitude, longitude and elevation) with assets which integrates with the Asset Map tool found on Desktop (Browser, HTTPS Protocol). The geoshape meta-data are stored in the document type geoshape.

Geoshapes can be of various types: point, polyline, rectangle, polygon, compound (combining simple shapes). The system also supports holes inside shapes.

Creating Assets with a GeoShape

You can use Mediaflux Desktop Asset Finder to input the GeoShape information (shape tab in the asset creation GUI) or the service layer API.

Here are some example service commands executed from aterm creating assets with asset.create and using asset.set for pre-existing assets. The choice of coordinate reference frames is : WGS84 (default), NAD27, GRS80

Point

> asset.create :namespace neil :geoshape -datum WGS84 -type point < :point  < :longitude 153.4  :latitude  -37.0 >  >

> asset.set :id 2XXXX506 :geoshape -datum WGS84 -type point < :point  < :longitude 153.4  :latitude  -37.0 >  >

Poly-Line

> asset.create :namespace neil :geoshape -datum WGS84 -type polyline < :point  < :longitude 155.4  :latitude  -38.0 > :point  < :longitude 155.4  :latitude  -39.0 >  :point  < :longitude 155.4  :latitude  -40.0 >  >

> asset.set :id 2XXXX506 :geoshape -datum WGS84 -type polyline < :point  < :longitude 155.4  :latitude  -38.0 > :point  < :longitude 155.4  :latitude  -39.0 >  :point  < :longitude 155.4  :latitude  -40.0 >  >

Rectangle

Only 2 points allowed.

> asset.create :namespace neil :geoshape -datum WGS84 -type rectangle < :point  < :longitude 155.4  :latitude  -38.0 > :point  < :longitude 155.4  :latitude  -39.0 > >

> asset.set :id 2XXXX506 :geoshape -datum WGS84 -type rectangle < :point  < :longitude 155.4  :latitude  -38.0 > :point  < :longitude 155.4  :latitude  -39.0 > >

This screen shot shows these three geoshape types (there are 4 points) overlaid on Google Maps.

Querying for GeoShapes

Find any asset of a particular geoshape type

> asset.query :where geoshape any
> asset.query :where geoshape point
> asset.query :where geoshape rectangle
> asset.query :where geoshape polyline

Find assets with specific geoshape types inside a range

This query finds all point geoshapes inside a rectangle specified as two (lat, long) pairs. The square brackets must be escaped from ATERM.

> asset.query :where geoshape point and geoshape inside rectangle \[(-40.0,150.0), (-30.0,160.0)\]

Additional information

For reference, here is Arcitecta's technical note (PDF).

There is also a video amongst the Mediaflux Desktop - How-to videos (entitled Introduction to Asset Map) with some basic information on how to use the Asset Map tool inside Mediaflux Desktop.