AR1/docs/import/raster.md

Raster Data Import

Import raster data from files, URLs, or cloud storage.

Overview

Raster data import supports multiple formats and import methods for grid-based spatial data.

Supported Formats

GeoTIFF

• Extension: .tif, .tiff, .gtif
• Description: Georeferenced TIFF format
• Features: Full support for multi-band rasters, overviews, compression

Cloud Optimized GeoTIFF (COG)

• Extension: .tif, .tiff
• Description: Cloud-optimized GeoTIFF format
• Features: Optimized for cloud storage and streaming
• Benefits: Efficient access to large rasters

Other Formats

• JPEG2000: .jp2, .j2k
• PNG: .png (with world file)
• NetCDF: .nc, .nc4
• HDF: .hdf, .h5

Import Methods

File Upload

Upload raster files directly:

1. Navigate to raster upload page
2. Select file or drag and drop
3. Add optional description
4. Configure import options
5. Click "Upload"

File Size Limit: Configurable (default: 100MB+)

URL Import

Import from web-accessible URLs:

1. Navigate to URL import page
2. Enter raster URL
3. Configure import options
4. Optionally schedule import
5. Click "Import"

S3 Bucket Import

Import from AWS S3 buckets:

1. Navigate to S3 import page
2. Configure AWS credentials
3. Select bucket and file
4. Configure import mode
5. Click "Import"

Import Modes:

• Serve COG: Register as remote COG (no download)
• Download PostGIS: Download and import to PostGIS

GeoServer Import

Import from GeoServer WCS:

1. Navigate to GeoServer import page
2. Select workspace and layer
3. Configure import options
4. Click "Import"

Import Process

Step 1: File Validation

Raster file is validated:

• Format detection
• GDAL availability check
• File integrity verification
• Metadata extraction

Step 2: Metadata Extraction

Metadata extracted using GDAL:

• Spatial reference system (SRID)
• Bounding box
• Pixel size
• Band count
• Data type
• NoData values

Step 3: PostGIS Import

Raster imported into PostGIS using raster2pgsql:

raster2pgsql -s {srid} -t {tile_size} {file} {schema}.{table} | psql

Options:

• Tile Size: Default 256x256 pixels
• Schema: Default 'public'
• Table Name: Auto-generated or specified
• SRID: Detected from file or specified

Step 4: Registration

Raster registered in system:

• Metadata stored in aurora_raster_layers table
• Layer name assigned
• Access permissions set
• Preview generation

Configuration Options

Tile Size

Configure raster tiling:

• 256x256: Default, good for most cases
• 512x512: Larger tiles, fewer database rows
• 128x128: Smaller tiles, more database rows

Import Mode

For S3/URL imports:

• Serve COG: Register remote COG, no local storage
• Download PostGIS: Download and import to PostGIS

Compression

Configure raster compression:

• None: No compression
• JPEG: Lossy compression
• LZW: Lossless compression
• Deflate: Lossless compression

Example: GeoTIFF Upload

# Via API
curl -X POST "https://example.com/raster_upload.php" \
  -F "raster_file=@elevation.tif" \
  -F "description=Digital elevation model" \
  -F "tile_size=256x256"

Example: S3 Import

# Via API
curl -X POST "https://example.com/raster_bucket_import_api.php" \
  -d "url=s3://bucket/path/to/raster.tif" \
  -d "mode=download_postgis" \
  -d "aws_access_key_id=..." \
  -d "aws_secret_access_key=..."

Cloud Optimized GeoTIFF (COG)

COG format provides:

• Efficient Streaming: Access specific regions without full download
• Cloud Storage: Optimized for S3, Azure, GCS
• Performance: Fast access to large rasters
• Cost Effective: Reduced bandwidth usage

Creating COGs

Use GDAL to create COG:

gdal_translate input.tif output.tif \
  -of COG \
  -co COMPRESS=LZW \
  -co TILED=YES

Troubleshooting

Common Issues

GDAL not available

• Install GDAL: apt-get install gdal-bin (Ubuntu)
• Verify: gdalinfo --version
• Check PATH configuration

Large file timeout

• Increase PHP execution time
• Use background import
• Consider chunked upload

SRID not detected

• Check raster metadata
• Specify SRID manually
• Verify projection information

Memory issues

• Increase PHP memory limit
• Use tile-based processing
• Consider resampling large rasters

Related Documentation

• Vector Import
• PostGIS Import
• ESRI Import
• Raster Analysis Tools