gdar-sar 1.2.0.post3

GDAR-SAR -- Synthetic aperture radar geometry and functionality for GDAR

gdar-sar

Synthetic aperture radar geometry and functionality for the GDAR processing framework. Part of the OpenGDAR family of packages. Requires gdar-base and gdar-orbit.

Type registration

gdar.sar.meta and gdar.sar.refsys define subtypes of gdar.base.Meta and gdar.base.Meta_refsys that must be registered before they can be instantiated. Registration happens automatically when you import gdar.sar, so make sure this import occurs in your Python context before creating any SAR Meta or Meta_refsys objects. When reading files with read_gdr(), the reader handles this for you.

Modules

gdar.sar.meta -- SAR metadata

SAR-specific metadata extending the base Meta class:

• Meta_sar -- metadata container for SAR rasters (Doppler centroid, pulse repetition frequency, chirp parameters, etc.).
• create_doppler_grid() -- generate a grid of Doppler centroid values across the raster.

gdar.sar.refsys -- Reference systems

SAR coordinate reference system definitions used by DataRaster geometry methods:

• Meta_refsys_mssar_zd_sr -- monostatic SAR, zero-Doppler, slant-range reference system.
• Meta_refsys_mssar_zd_gr -- monostatic SAR, zero-Doppler, ground-range reference system.
• Meta_refsys_bssar_bmcd_sr -- bistatic SAR, beam-centre Doppler, slant-range reference system.

gdar.sar.bistatic_geometry -- Bistatic SAR geometry

Geometry routines for bistatic (e.g. TanDEM-X) configurations:

• BistaticGeometry -- class encapsulating transmitter/receiver orbits and the bistatic range equation.
• bistatic_from_meta() -- construct a BistaticGeometry from raster metadata.
• bistatic_geod_from_coord() -- convert SAR coordinates to geodetic.
• bistatic_xyz2sar() -- convert Cartesian XYZ to SAR coordinates.
• brange_from_azel() -- compute bistatic range from azimuth and elevation.

gdar.sar.rastertools -- Raster processing utilities

Higher-level functions operating on SAR DataRaster objects:

• back_geocode_dem() / back_geocode_raster() -- back-geocode a DEM or raster using SAR geometry.
• grd_merger() -- merge multiple GRD products into one raster.
• band_split_pixels() / band_split_parameters() -- spectral band splitting for split-spectrum InSAR.
• azimuth_splitter() / range_splitter() -- split an SLC in azimuth or range.
• slc_processing_meta() -- build metadata for SLC processing steps.
• update_trajectory() -- replace a raster's trajectory with a precision orbit.
• is_descending() -- check whether the orbit pass is descending.

gdar.sar.metatools -- Metadata helpers

• update_bmeta_with_brefsys() -- update bistatic metadata with a beam-centre reference system.

Installation

Install from PyPI:

pip install gdar-sar

or with uv:

uv pip install gdar-sar

Dependencies (including gdar-base and gdar-orbit) are installed automatically.

Optional extras:

• crs — map projections and geocoding (requires GDAL; see the gdar-base README for GDAL installation instructions)
• plotting — matplotlib
• interactive — IPython

pip install "gdar-sar[crs,plotting]"

Testing

pytest tests/

Development

Installing from the NORCE GitLab registry

Internal users and contributors can install pre-release versions from the NORCE GitLab package registry. Authenticate with either a deploy token or a personal access token:

• Deploy token: From the earth-observation/opengdar group page in GitLab, go to Settings → Repository → Deploy Tokens and create a token with the read_package_registry scope. The username is the auto-assigned name shown when the token is created (e.g. gitlab+deploy-token-42).
• Personal access token: Create a new access token in GitLab with the read_api scope. The username for personal tokens is __token__.

Set the following environment variables:

# bash / zsh
export UV_INDEX_OPENGDAR_USERNAME=<username>
export UV_INDEX_OPENGDAR_PASSWORD=<token>

Then build the environment:

uv venv --python 3.12
uv sync

If you need GDAL/CRS support, install the GDAL build prerequisites first (see the gdar-base README), then:

uv pip install numpy setuptools
uv pip install --no-build-isolation "gdal==$(gdal-config --version)"
uv sync --extra crs

Internal links

• GDAR wiki — central documentation hub
• OpenGDAR API Reference — auto-generated from docstrings
• Release schedule

License

This project is licensed under the Apache License, Version 2.0. You may obtain a copy of the license at https://www.apache.org/licenses/LICENSE-2.0 or in the LICENSE file distributed with this source.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.