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Point Cloud Extension Specification
- Title: Point Cloud
- Identifier: https://stac-extensions.github.io/pointcloud/v2.0.0/schema.json
- Field Name Prefix: pc
- Scope: Item, Collection
- Extension Maturity Classification: Pilot
- Owner: @matthewhanson
- History: Prior to March 2, 2021
This document explains the Point Cloud Extension to the SpatioTemporal Asset Catalog (STAC) specification. It adds fields to a STAC Item, to enable STAC to more fully describe point cloud datasets. The point clouds can come from either active or passive sensors, and data is frequently acquired using tools such as LiDAR or coincidence-matched imagery.
Item Properties
| Field Name | Type | Description |
|---|---|---|
| pc:count | integer | REQUIRED. The number of points in the Item. |
| pc:type | string | REQUIRED. Phenomenology type for the point cloud. Possible valid values might include lidar, eopc, radar, sonar, or other |
| pc:schemas | [Schema Object] | A sequential array of Items that define the dimensions and their types. |
| pc:density | number | Number of points per square unit area. |
| pc:statistics | [Stats Object] | A sequential array of Items mapping to pc:schemas defines per-channel statistics. |
Schema Object
A sequential array of Items that define the dimensions or channels of the point cloud, their types, and their sizes (in full bytes).
| Field Name | Type | Description |
|---|---|---|
| name | string | REQUIRED. The name of the dimension. |
| size | integer | REQUIRED. The size of the dimension in bytes. Whole bytes only are supported. |
| type | string | REQUIRED. Dimension type. Valid values are floating, unsigned, and signed |
Stats Object
A sequential array of Items mapping to pc:schemas defines per-channel statistics. The channel name is required and at least one statistic.
| Field Name | Type | Description |
|---|---|---|
| name | string | REQUIRED. The name of the channel. |
| position | integer | Position of the channel in the schema. |
| average | number | The average of the channel. |
| count | integer | The number of elements in the channel. |
| maximum | number | The maximum value of the channel. |
| minimum | number | The minimum value of the channel. |
| stddev | number | The standard deviation of the channel. |
| variance | number | The variance of the channel. |
Contributing
All contributions are subject to the STAC Specification Code of Conduct. For contributions, please follow the STAC specification contributing guide Instructions for running tests are copied here for convenience.
Running tests
The same checks that run as checks on PR's are part of the repository and can be run locally to verify that changes are valid.
To run tests locally, you'll need npm, which is a standard part of any node.js installation.
First you'll need to install everything with npm once. Just navigate to the root of this repository and on your command line run:
npm install
Then to check markdown formatting and test the examples against the JSON schema, you can run:
npm test
This will spit out the same texts that you see online, and you can then go and fix your markdown or examples.
If the tests reveal formatting problems with the examples, you can fix them with:
npm run format-examples