GeoEmbed

NetCL-based visual feature encoders for aerial and satellite imagery.

What It Can Do

• 256d L2-Normalized Vectors: Encodes aerial and satellite imagery into compact 256-dimensional unit vectors ($|z|_2 = 1.0$).
• Direct Similarity Measurement: Vector dot product directly yields cosine similarity in $[-1.0, 1.0]$:

$$S(z_1, z_2) = z_1 \cdot z_2$$

• Environmental Invariance: Stable across multi-year temporal drift, seasons, foliage changes, sun angles, and illumination conditions.
• Topological & Semantic Structure: Captures road networks, parcel boundaries, forested areas, water bodies, and built-up patterns.
• Unsupervised Clustering: Latent vectors organically group semantic landscape and terrain types without manual labels:

Reference Orthophoto	Continuous Latent Field (PCA)	Low Cluster ($k=2$)

Low Cluster ($k=3$)	Low Cluster ($k=4$)	Cluster Map ($k=6$)

Cluster Map ($k=8$)	Cluster Map ($k=10$)	Cluster Map ($k=20$)

At low cluster counts ($k=2, 3, 4$), the embedding space separates macroscopic terrain classes (dense forest vs. open agricultural land). As $k$ increases ($k=6, 8, 10, 20$), granular sub-structures such as access roads, parcel boundaries, and built forms emerge organically.

Data source of sample orthophotos: © LGL Baden-Württemberg (www.lgl-bw.de), licensed under dl-de/by-2-0. See ATTRIBUTION.md for details.

• Downstream Applications:
  • Unsupervised land-cover segmentation and zone maps
  • Parcel and boundary structure delineation
  • Temporal change detection across multi-year captures
  • Visual localization and map matching against orthophoto databases

What It Expects as Input

• Image Type: Nadir aerial and satellite imagery (orthophotos, top-down perspective).
• Format: File path (str / Path), PIL Image, or NumPy array.
• Color Channels: 3-channel RGB (automatically converted and normalized to $[-1.0, 1.0]$).
• Geometry: Square image tiles.
• Preferred Ground Scale / Zoom Level: z=18 Web-Mercator ($\approx 0.5\text{ m/pixel}$ GSD). The encoders are natively calibrated for $z=18$ aerial tiles. Any single, consistent scale works as long as queries and reference index match, but $z=18$ provides optimal feature separation.

Limitations

• No Scale Invariance: The models deliberately do not enforce cross-scale invariance to preserve fine discriminative details. All tiles in an index and query set must share the same ground scale (preferably $z=18$). Mixing different zoom levels (e.g. $z=16$ and $z=18$) leads to scale aliasing and false matches.
• Nadir Perspective Only: Strictly top-down orthophotos. Oblique aerial imagery, perspective drone shots, or street-level photos are not supported.
• RGB Only: Standard 3-channel RGB. Multispectral, near-infrared (NIR), or synthetic-aperture radar (SAR) imagery are not supported without prior conversion.

Code

from geoembed import Model

# Default model (v3)
model = Model()

# Alternative iterations
model = Model.v11()
model = Model.v12()

# Encode a single image -> (256,) L2-normalized vector
vector = model.encode("tile.png")

# Encode a batch of images -> (N, 256) NumPy array
vectors = model.encode(["tile_a.png", "tile_b.png"])

# Cosine similarity between two images -> float in [-1.0, 1.0]
sim = model.similarity("tile_a.png", "tile_b.png")
print(f"Similarity: {sim:.4f}")