Create a collection

How to create a (very tiny) STAC catalog¶

In this sections we present how to create a very tiny STAC catalog from python with pystac.

Code¶

First, we need to import pystac and datetime modules:

import pystac
from datetime import datetime

We create a pystac.Collection. Note that we provide an undefined extent for now:

col1 = pystac.Collection(
    id="collection-test1",
    extent=pystac.Extent(
        pystac.SpatialExtent(4 * [0]),
        pystac.TemporalExtent(intervals=[[None, None]]),
    ),
    description="Some collection for tests",
    title="Collection test 1",
)

You can take a look at the pystac.Collection class in the API reference here (there is plenty of interesting stuff like license, providers, keywords, etc.).

Then we instantiate a pystac.Item. Members datetime, id, bbox, properties and geometry are required. We set 2 assets using the assets dict. In our example, both assets media_type are set to COG (Cloud Optimized-Geotiff), implying that the two files identified with href must be in COG format.

item1 = pystac.Item(
    id="item_23102024",
    datetime=datetime(year=2024, month=10, day=23),
    bbox=[2.49, 46.59, 3.26, 47.14],
    geometry={
        "type": "Polygon",
        "coordinates": [
            [[2.49, 47.14], [3.26, 47.13], [3.25, 46.59], [2.49, 46.59], [2.49, 47.14]]
        ],
    },
    assets={
        "estim": pystac.Asset(href="/tmp/estim.tif", media_type=pystac.MediaType.COG),
        "conf": pystac.Asset(href="/tmp/conf.tif", media_type=pystac.MediaType.COG),
    },
    properties={},
)

We can then add item1 to the col1 collection:

col1.add_item(item1)

Now we can update very conveniently the collection extents (both temporal and spatial) with the following:;

col1.update_extent_from_items()

We can finally save our collection into a .json file:

col1.normalize_hrefs("/tmp/collection-test1")
col1.save(pystac.CatalogType.ABSOLUTE_PUBLISHED)

And voila !

Result¶

Generated files¶

/tmp/collection-test1/
├── collection.json
└── item_23102024
    └── item_23102024.json

collection.json¶

Code

{
  "type": "Collection",
  "id": "collection-test1",
  "stac_version": "1.1.0",
  "description": "Some collection for tests",
  "links": [
    {
      "rel": "root",
      "href": "/tmp/collection-test1/collection.json",
      "type": "application/json",
      "title": "Collection test 1"
    },
    {
      "rel": "item",
      "href": "/tmp/collection-test1/item_23102024/item_23102024.json",
      "type": "application/geo+json"
    },
    {
      "rel": "self",
      "href": "/tmp/collection-test1/collection.json",
      "type": "application/json"
    }
  ],
  "title": "Collection test 1",
  "extent": {
    "spatial": {
      "bbox": [
        [
          2.49,
          46.59,
          3.26,
          47.14
        ]
      ]
    },
    "temporal": {
      "interval": [
        [
          "2024-10-23T00:00:00Z",
          "2024-10-23T00:00:00Z"
        ]
      ]
    }
  },
  "license": "other"
}

item_23102024.json¶