Add get origin func to COG

[sharkAndshark]

It's the 2nd PR of #1814 to fix #1820

A func to get the origin coord from COG is added. It's highly inspired by geotiff.js and the content of B.6 of geotiff spec

[Copilot]

Pull Request Overview

Adds a helper to extract the spatial origin from a COG’s GeoTIFF tags and integrates it into the metadata.

• Introduce origin field in Meta and call a new get_origin function in get_meta
• Implement get_origin to read either the first ModelTiepointTag or the Transformation matrix
• Add corresponding error variant, unit tests, and update dependencies

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
martin/src/cog/source.rs	Added origin field, implemented get_origin, integrated into get_meta, and added tests
martin/src/cog/errors.rs	Introduced GetOriginFailed error variant
martin/Cargo.toml	Added approx dev-dependency and reordered testcontainers-modules

Comments suppressed due to low confidence (2)

martin/src/cog/errors.rs:56

• [nitpick] Consider enriching this error message with context, such as indicating whether both tie points and transformation tags were missing or invalid.

#[error("Get origin failed for {0}")]

martin/src/cog/source.rs:593

• Add a unit test for the failure case (e.g., both tie_points and transformation are None) to cover the error branch in get_origin.

}

[Copilot]

Pull Request Overview

This PR adds a new function to extract the origin coordinate from a Cloud Optimized GeoTIFF (COG) using either tie points or a transformation matrix as defined in the GeoTIFF specification. Key changes include:

• Adding an origin field to the Meta struct in source.rs.
• Implementing and integrating the get_origin function to calculate the origin based on provided tie points or transformation matrix.
• Adding corresponding tests to verify get_origin behavior.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
martin/src/cog/source.rs	Adds the origin field to Meta, implements get_origin, and integrates it within get_meta along with tests.
martin/src/cog/errors.rs	Adds a GetOriginFailed error variant for failure cases in get_origin.
martin/Cargo.toml	Adds approx as a dev-dependency for testing purposes.

Comments suppressed due to low confidence (1)

martin/src/cog/source.rs:576

• [nitpick] The test parameters are named 'matrix' and 'tie_point', but they are passed to get_origin in reversed order relative to the function signature. Consider renaming the test parameters to match the function parameter order for clarity.

fn can_get_origin(

[Copilot]

Pull Request Overview

Adds support for extracting the geographic origin from a Cloud-Optimized GeoTIFF by introducing a new origin field on Meta and a helper to compute it from GeoTIFF tags.

• Extend Meta with a 3-element origin coordinate and populate it in get_meta.
• Implement get_origin to derive the origin from either tie points or a transformation matrix, plus associated error variant and tests.
• Add approx as a dev-dependency for floating-point comparisons in tests.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
martin/src/cog/source.rs	Added origin field, implemented get_origin, and tests
martin/src/cog/errors.rs	Introduced GetOriginFailed error variant
martin/Cargo.toml	Added approx under [dev-dependencies] for test assertions

Comments suppressed due to low confidence (1)

martin/src/cog/source.rs:426

• Add a test case for when both tie_points and transformation are None to exercise the GetOriginFailed error path.

fn get_origin(

[CommanderStorm]

If you add some documentation in the form if doc comments what an origin is, I am fine with this.
I honestly don't have a good understanding what an origin is.

[CommanderStorm]

Could you add doc comments explaining what the origin is?
This would be very handy as origin as 3*f64 is not quite self-explanatory.

[sharkAndshark]

Hmm. I will try. Actually it's the coords: raster_space_to_model_space(0,0,0), I'm not good at this, maybe you have better one?
I add this to:

    // The geo coords of pixel(0, 0, 0) ordering in [x, y, z]
    origin: [f64; 3],