Running the step

Goal¶

Run norm_diff in the same Hatch environment used by the practice notebook. The notebook is stored at practice-labs/1-Application_Steps/normalized-difference.ipynb.

Requirements¶

Install Python 3.12 or newer, Hatch, and Task. Run the crop lab first to create crop_green.tif and crop_nir.tif. See developer tooling for the available tasks.

Register the notebook kernel¶

From the checkout root, run:

task kernel:install TOOL=norm_diff

Select Bash (norm_diff Hatch) in Jupyter or VS Code. This kernel uses the package's default Hatch environment. An ordinary Bash kernel can also activate that environment using the commands below. Run the workspace setup from inside the checkout so Git can locate its root.

Configure the workspace¶

export WORKSPACE="$(git rev-parse --show-toplevel)"
export RUNTIME=${WORKSPACE}/runs
mkdir -p "${RUNTIME}"
cd "${RUNTIME}"

Outputs are written to runs/ in the current checkout.

Activate the Hatch environment¶

cd "${WORKSPACE}/water-bodies/command-line-tools/norm_diff"
hatch env create default
source "$(hatch env find default)/bin/activate"
cd "${RUNTIME}"

which python
which norm_diff
norm_diff --help

Hatch installs the Python project and its dependencies; a separate pip install cell is unnecessary. Activation keeps the console command available after changing to the output directory.

Run the step¶

norm_diff \
    --rasters crop_green.tif \
    --rasters crop_nir.tif

Supply exactly two rasters with repeated --rasters options. Their dimensions, transforms, and coordinate systems must match.

Expected outcome¶

The step adds these files under runs/:

norm_diff.tif

Earlier steps' outputs remain available.

Finish the session¶

deactivate

Keep the Hatch environment for subsequent runs. The pip-based scripts under scripts/ remain an alternative for manual shell use.