Official Implementation of "GAIR: Location-Aware Self-Supervised Contrastive Pre-Training with Geo-Aligned Implicit Representations"

GAIR is a location-aware self-supervised pre-training framework for learning geo-aligned representations from remote sensing imagery, street-view imagery, and geographic coordinates.

This repository currently releases the inference code for GAIR. This repo includes

• loading the pretrained GAIR checkpoint
• extracting remote sensing (RS) embeddings
• extracting street-view (SV) embeddings
• extracting location embeddings
• querying localized RS embeddings with the NILI module

The pretraining dataset and pretraining code are still being organized and will be released later.

Installation

conda create -n gair python=3.10 -y
conda activate gair
python -m pip install --upgrade pip
pip install torch==2.3.0 torchvision==0.18.0 torchaudio==2.3.0 \
  --index-url https://download.pytorch.org/whl/cu118
pip install -r requirements.txt
python -c "import torch; print(torch.__version__); print(torch.version.cuda); print(torch.cuda.is_available())"

torch.cuda.is_available() should print True.

If you need a different CUDA wheel, replace only the PyTorch install command above and keep the remaining steps unchanged.

Quick Start

Python API

import torch

from huggingface_hub import hf_hub_download
from gair import GAIRModel, load_rs_image, load_sv_image, preprocess_rs_array, preprocess_sv_array

checkpoint = hf_hub_download(repo_id="PingL/GAIR", filename="checkpoint.pth")
device = "cuda:0" if torch.cuda.is_available() else "cpu"

model = GAIRModel.from_checkpoint(checkpoint, device=device, query_mode="nili")

rs = preprocess_rs_array(load_rs_image("path/to/rs_crop.tif")).to(device)
sv = preprocess_sv_array(load_sv_image("path/to/street_view.jpg")).to(device)
coords = torch.tensor([[116.397, 39.908]], device=device)  # [lon, lat]
bbox = torch.tensor([[116.387, 39.918, 116.407, 39.898]], device=device)  # bbox of the rs image, [lon_min, lat_max, lon_max, lat_min]

with torch.inference_mode():
    rs_embedding = model.encode_rs(rs, normalize=True)
    sv_embedding = model.encode_sv(sv, normalize=True)
    loc_embedding = model.encode_location(coords, normalize=True)
    _, localized_rs_embedding = model.query_localized_rs(
        rs,
        coords,
        bbox,
        mode="nili",
        normalize=True,
    )

Command Line Inference

CHECKPOINT=$(hf download PingL/GAIR checkpoint.pth)

python scripts/extract_embeddings.py \
  --checkpoint "$CHECKPOINT" \
  --rs-image path/to/rs_crop.tif \
  --sv-image path/to/street_view.jpg \
  --lon 116.397 \
  --lat 39.908 \
  --rs-bbox 116.387 39.918 116.407 39.898 \
  --query-mode nili \
  --normalize \
  --output-dir outputs/demo

The script exports:

• rs_embedding.npy
• sv_embedding.npy
• loc_embedding.npy
• localized_rs_embedding.npy

Embedding Examples

Bundled satellite, street-view, and geolocation examples are provided in examples/extract_embeddings.

Run:

CHECKPOINT=$(hf download PingL/GAIR checkpoint.pth)

python scripts/demo_extract_example_embeddings.py \
  --checkpoint "$CHECKPOINT"

This saves RS, SV, location, and localized RS embeddings for each bundled example under outputs/example_embeddings/.

Retrieval Demo

A tiny localized RS-to-street-view retrieval demo is included in examples/rs_to_sv_retrieval/README.md.

Run:

CHECKPOINT=$(hf download PingL/GAIR checkpoint.pth)

python scripts/demo_localized_rs_to_sv_retrieval.py \
  --checkpoint "$CHECKPOINT"

This demo uses 3 remote sensing queries and 3 street-view gallery images bundled in the repository, and saves one preview image per query under outputs/rs_to_sv_retrieval_demo/.

Input Conventions

• RS crop bbox order: [lon_min, lat_max, lon_max, lat_min]
• Coordinate order: [lon, lat]
• --rs-image should already be the RS crop corresponding to --rs-bbox
• RS inputs should be 10-band Sentinel-2 image (B2, B3, B4, B5, B6, B7, B8, B8A, B11, B12).

Query Modes

• nili: learned NILI query used by GAIR
• bilinear: deterministic interpolation baseline
• bicubic: deterministic interpolation baseline

Citation

If you find this repository useful for your research, please consider citing our paper:

@article{liu2026gair,
  title   = {GAIR: Location-aware Self-supervised Contrastive Pre-training with Geo-aligned Implicit Representations},
  author  = {Liu, Zeping and Lao, Ni and Wang, Zhangyu and Jiao, Junfeng and Mai, Gengchen},
  journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
  volume  = {237},
  pages   = {166--182},
  year    = {2026},
  publisher = {Elsevier}
}