Machine Learning for Geospatial Data

Guide to ML and deep learning applications for remote sensing and spatial analysis.

Traditional Machine Learning

Random Forest for Land Cover

from sklearn.ensemble import RandomForestClassifier
from sklearn.model_selection import train_test_split
from sklearn.metrics import classification_report, confusion_matrix

from rasterio.features import rasterize

def train_random_forest_classifier(raster_path, training_gdf):
    """Train Random Forest for image classification."""

    # Load imagery
    with rasterio.open(raster_path) as src:
        image = src.read()
        profile = src.profile
        transform = src.transform

    # Extract training data
    X, y = [], []

    for _, row in training_gdf.iterrows():
        mask = rasterize(
            [(row.geometry, 1)],
            out_shape=(profile['height'], profile['width']),
            transform=transform,
            fill=0,
            dtype=np.uint8
        )
        pixels = image[:, mask > 0].T
        X.extend(pixels)
        y.extend([row['class_id']] * len(pixels))

    X = np.array(X)
    y = np.array(y)

    # Split data
    X_train, X_val, y_train, y_val = train_test_split(
        X, y, test_size=0.2, random_state=42, stratify=y
    )

    # Train model
    rf = RandomForestClassifier(
        n_estimators=100,
        max_depth=20,
        min_samples_split=10,
        min_samples_leaf=4,
        class_weight='balanced',
        n_jobs=-1,
        random_state=42
    )
    rf.fit(X_train, y_train)

    # Validate
    y_pred = rf.predict(X_val)
    print("Classification Report:")
    print(classification_report(y_val, y_pred))

    # Feature importance
    feature_names = [f'Band_{i}' for i in range(X.shape[1])]
    importances = pd.DataFrame({
        'feature': feature_names,
        'importance': rf.feature_importances_
    }).sort_values('importance', ascending=False)

    print("\
Feature Importance:")
    print(importances)

    return rf

# Classify full image
def classify_image(model, image_path, output_path):
    with rasterio.open(image_path) as src:
        image = src.read()
        profile = src.profile

    image_reshaped = image.reshape(image.shape[0], -1).T
    prediction = model.predict(image_reshaped)
    prediction = prediction.reshape(image.shape[1], image.shape[2])

    profile.update(dtype=rasterio.uint8, count=1)
    with rasterio.open(output_path, 'w', **profile) as dst:
        dst.write(prediction.astype(rasterio.uint8), 1)

Support Vector Machine

from sklearn.svm import SVC
from sklearn.preprocessing import StandardScaler

def svm_classifier(X_train, y_train):
    """SVM classifier for remote sensing."""

    # Scale features
    scaler = StandardScaler()
    X_train_scaled = scaler.fit_transform(X_train)

    # Train SVM
    svm = SVC(
        kernel='rbf',
        C=100,
        gamma='scale',
        class_weight='balanced',
        probability=True
    )
    svm.fit(X_train_scaled, y_train)

    return svm, scaler

# Multi-class classification
def multiclass_svm(X_train, y_train):
    from sklearn.multiclass import OneVsRestClassifier

    scaler = StandardScaler()
    X_train_scaled = scaler.fit_transform(X_train)

    svm_ovr = OneVsRestClassifier(
        SVC(kernel='rbf', C=10, probability=True),
        n_jobs=-1
    )
    svm_ovr.fit(X_train_scaled, y_train)

    return svm_ovr, scaler

Deep Learning

CNN with TorchGeo

from torch.utils.data import DataLoader

# Define CNN
class LandCoverCNN(nn.Module):
    def __init__(self, in_channels=12, num_classes=10):
        super().__init__()
        self.encoder = nn.Sequential(
            nn.Conv2d(in_channels, 64, 3, padding=1),
            nn.BatchNorm2d(64),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(64, 128, 3, padding=1),
            nn.BatchNorm2d(128),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(128, 256, 3, padding=1),
            nn.BatchNorm2d(256),
            nn.ReLU(),
            nn.MaxPool2d(2),
        )

        self.decoder = nn.Sequential(
            nn.ConvTranspose2d(256, 128, 2, stride=2),
            nn.BatchNorm2d(128),
            nn.ReLU(),

            nn.ConvTranspose2d(128, 64, 2, stride=2),
            nn.BatchNorm2d(64),
            nn.ReLU(),

            nn.ConvTranspose2d(64, num_classes, 2, stride=2),
        )

    def forward(self, x):
        x = self.encoder(x)
        x = self.decoder(x)
        return x

# Training
def train_model(train_loader, val_loader, num_epochs=50):
    device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
    model = LandCoverCNN().to(device)

    criterion = nn.CrossEntropyLoss()
    optimizer = torch.optim.Adam(model.parameters(), lr=0.001)

    for epoch in range(num_epochs):
        model.train()
        train_loss = 0

        for images, labels in train_loader:
            images, labels = images.to(device), labels.to(device)

            optimizer.zero_grad()
            outputs = model(images)
            loss = criterion(outputs, labels)
            loss.backward()
            optimizer.step()

            train_loss += loss.item()

        # Validation
        model.eval()
        val_loss = 0
        with torch.no_grad():
            for images, labels in val_loader:
                images, labels = images.to(device), labels.to(device)
                outputs = model(images)
                loss = criterion(outputs, labels)
                val_loss += loss.item()

        print(f'Epoch {epoch+1}/{num_epochs}, Train Loss: {train_loss:.4f}, Val Loss: {val_loss:.4f}')

    return model

U-Net for Semantic Segmentation

class UNet(nn.Module):
    def __init__(self, in_channels=4, num_classes=5):
        super().__init__()

        # Encoder
        self.enc1 = self.conv_block(in_channels, 64)
        self.enc2 = self.conv_block(64, 128)
        self.enc3 = self.conv_block(128, 256)
        self.enc4 = self.conv_block(256, 512)

        # Bottleneck
        self.bottleneck = self.conv_block(512, 1024)

        # Decoder
        self.up1 = nn.ConvTranspose2d(1024, 512, 2, stride=2)
        self.dec1 = self.conv_block(1024, 512)

        self.up2 = nn.ConvTranspose2d(512, 256, 2, stride=2)
        self.dec2 = self.conv_block(512, 256)

        self.up3 = nn.ConvTranspose2d(256, 128, 2, stride=2)
        self.dec3 = self.conv_block(256, 128)

        self.up4 = nn.ConvTranspose2d(128, 64, 2, stride=2)
        self.dec4 = self.conv_block(128, 64)

        # Final layer
        self.final = nn.Conv2d(64, num_classes, 1)

    def conv_block(self, in_ch, out_ch):
        return nn.Sequential(
            nn.Conv2d(in_ch, out_ch, 3, padding=1),
            nn.BatchNorm2d(out_ch),
            nn.ReLU(inplace=True),
            nn.Conv2d(out_ch, out_ch, 3, padding=1),
            nn.BatchNorm2d(out_ch),
            nn.ReLU(inplace=True)
        )

    def forward(self, x):
        # Encoder
        e1 = self.enc1(x)
        e2 = self.enc2(F.max_pool2d(e1, 2))
        e3 = self.enc3(F.max_pool2d(e2, 2))
        e4 = self.enc4(F.max_pool2d(e3, 2))

        # Bottleneck
        b = self.bottleneck(F.max_pool2d(e4, 2))

        # Decoder with skip connections
        d1 = self.dec1(torch.cat([self.up1(b), e4], dim=1))
        d2 = self.dec2(torch.cat([self.up2(d1), e3], dim=1))
        d3 = self.dec3(torch.cat([self.up3(d2), e2], dim=1))
        d4 = self.dec4(torch.cat([self.up4(d3), e1], dim=1))

        return self.final(d4)

Change Detection with Siamese Network

class SiameseNetwork(nn.Module):
    """Siamese network for change detection."""

    def __init__(self):
        super().__init__()
        self.feature_extractor = nn.Sequential(
            nn.Conv2d(3, 32, 3, padding=1),
            nn.BatchNorm2d(32),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(32, 64, 3, padding=1),
            nn.BatchNorm2d(64),
            nn.ReLU(),
            nn.MaxPool2d(2),

            nn.Conv2d(64, 128, 3, padding=1),
            nn.BatchNorm2d(128),
            nn.ReLU(),
        )

        self.classifier = nn.Sequential(
            nn.Conv2d(256, 128, 3, padding=1),
            nn.ReLU(),
            nn.Conv2d(128, 64, 3, padding=1),
            nn.ReLU(),
            nn.Conv2d(64, 2, 1),  # Binary: change / no change
        )

    def forward(self, x1, x2):
        f1 = self.feature_extractor(x1)
        f2 = self.feature_extractor(x2)

        # Concatenate features
        diff = torch.abs(f1 - f2)
        combined = torch.cat([f1, f2, diff], dim=1)

        return self.classifier(combined)

Graph Neural Networks

PyTorch Geometric for Spatial Data

from torch_geometric.data import Data
from torch_geometric.nn import GCNConv

# Create spatial graph
def create_spatial_graph(points_gdf, k_neighbors=5):
    """Create graph from point data using k-NN."""

    from sklearn.neighbors import NearestNeighbors

    coords = np.array([[p.x, p.y] for p in points_gdf.geometry])

    # Find k-nearest neighbors
    nbrs = NearestNeighbors(n_neighbors=k_neighbors).fit(coords)
    distances, indices = nbrs.kneighbors(coords)

    # Create edge index
    edge_index = []
    for i, neighbors in enumerate(indices):
        for j in neighbors:
            edge_index.append([i, j])

    edge_index = torch.tensor(edge_index, dtype=torch.long).t().contiguous()

    # Node features
    features = points_gdf.drop('geometry', axis=1).values
    x = torch.tensor(features, dtype=torch.float)

    return Data(x=x, edge_index=edge_index)

# GCN for spatial prediction
class SpatialGCN(torch.nn.Module):
    def __init__(self, num_features, hidden_channels=64):
        super().__init__()
        self.conv1 = GCNConv(num_features, hidden_channels)
        self.conv2 = GCNConv(hidden_channels, hidden_channels)
        self.conv3 = GCNConv(hidden_channels, 1)

    def forward(self, data):
        x, edge_index = data.x, data.edge_index
        x = self.conv1(x, edge_index).relu()
        x = F.dropout(x, p=0.5, training=self.training)
        x = self.conv2(x, edge_index).relu()
        x = self.conv3(x, edge_index)
        return x

Explainable AI (XAI) for Geospatial

SHAP for Model Interpretation

def explain_model(model, X, feature_names):
    """Explain model predictions using SHAP."""

    # Create explainer
    explainer = shap.Explainer(model, X)

    # Calculate SHAP values
    shap_values = explainer(X)

    # Summary plot
    shap.summary_plot(shap_values, X, feature_names=feature_names)

    # Dependence plot for important features
    for i in range(X.shape[1]):
        shap.dependence_plot(i, shap_values, X, feature_names=feature_names)

    return shap_values

# Spatial SHAP (accounting for spatial autocorrelation)
def spatial_shap(model, X, coordinates):
    """Spatial explanation considering neighborhood effects."""

    # Compute SHAP values
    explainer = shap.Explainer(model, X)
    shap_values = explainer(X)

    # Spatial aggregation
    shap_spatial = {}
    for i, coord in enumerate(coordinates):
        # Find neighbors
        neighbors = find_neighbors(coord, coordinates, radius=1000)

        # Aggregate SHAP values for neighborhood
        neighbor_shap = shap_values.values[neighbors]
        shap_spatial[i] = np.mean(neighbor_shap, axis=0)

    return shap_spatial

Attention Maps for CNNs

def generate_attention_map(model, image_tensor, target_layer):
    """Generate attention map using Grad-CAM."""

    # Forward pass
    model.eval()
    output = model(image_tensor)

    # Backward pass
    model.zero_grad()
    output[0, torch.argmax(output)].backward()

    # Get gradients
    gradients = model.get_gradient(target_layer)

    # Global average pooling
    weights = torch.mean(gradients, axis=(2, 3), keepdim=True)

    # Weighted combination of activation maps
    activations = model.get_activation(target_layer)
    attention = torch.sum(weights * activations, axis=1, keepdim=True)

    # ReLU and normalize
    attention = F.relu(attention)
    attention = F.interpolate(attention, size=image_tensor.shape[2:],
                              mode='bilinear', align_corners=False)
    attention = (attention - attention.min()) / (attention.max() - attention.min())

    return attention.squeeze().cpu().numpy()

For more ML examples, see code-examples.md.