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Polar projection MERIS in the LearnEO! tutorial
Bilko 3.4 software
Bilko was first developed for UNESCO in 1987 to provide free image processing capability for education use. The software has since been updated regularly, to keep pace with developments in remote sensing technology. This included updates to support Envisat N1 data from AATSR, ASAR, MERIS and RA-2 soon after launch of the satellite.
LearnEO! has extended Bilko's capabilities to include support for data from ESA satellites such as ERS, SMOS and CryoSat, as well as along-track altimeter data from Envisat and Jason-2. The new version, for use with LearnEO! lessons, is now available to download.

Screenshot from the Amazon lesson using SMOS data

Principal Component Analysis in a Bilko mini-lesson

Screenshot from the El Niñno lesson

Screenshot from the lesson on Forest monitoring

Screenshot from a lesson on subpixel cloud.
Downloading and using Bilko
Software description
Platform and operating system
Bilko v.3.4 is designed to run on PCs running Windows 7 - 10, Windows Vista, and Windows XP. If you need a version that runs on an earlier operating system, please get in touch.
Bilko also runs on Intel Macs with
WINE (free),
Parallels or
VMware Fusion.
Quick guide to installing WINE and Bilko on a Mac (PDF).
Bilko should run in a similar way on Linux with WINE.
Software features
The Bilko tutorial covers most of the software features. Additional lessons for more recent features are available from the links below.
- Interactive and batch mode processing of up to 4096 images
- Extraction of time series data from specified locations
- Production of climatologies and anomaly data
- Supporting lesson: Extracting site specific SST time series data
- Supervised and unsupervised classification
- Parallelepiped, Centroid and Maximum likelihood
- Support for accuracy assessment, dendrograms and legends
- Supporting lesson: Supervised and unsupervised classification
- Principal Component Analysis
- Supporting lesson: Bilko mini-lesson no. 2
- Context sensitive help program
- Support for common image formats used in remote sensing
- Support for reading compressed image formats
- bzip2, gzip and zip
- currently limited to compressed NetCDF, ESA N1 and Sentinel-2 L1C data
- Handling of 3D and multiband data for up to 512 bands/images
- Actual capacity depends on image size and computer memory
- Support for 8-bit, 16-bit, 32-bit and floating point data
- Support for NaNs and customer defined Null values
- Image manipulation and display tools:
- Contrast stretching
- Application and design of colour palettes
- Display and creation of colour composites
- Zoom, Mirror, Flip and 180° rotation
- Colour bar, scroll-bars and status-bar displaying pixel information
- Full-Screen mode
- Customised display of 16-bit, 32-bit and floating-point data
- Extract tool for sub-sampling in the X, Y and Z dimensions
- Image editing and analysis tools:
- Animations
- Easy selection of specified points, lines and sub-areas
- Data-coring (spectral or time series)
- Transects, histograms, scatter-plots, Hovmöller diagrams
- Data processing tools:
- Predefined and custom designed filters
- Application of flags, masks, and coastlines
- Image calculations using formulae with sets of images
- Image rectification, resampling, and co-registration
- Geocorrection using Ground Control Points or tie-point tables
- Automatic geocorrection of Envisat and Earth Explorer data
- MERIS, ASAR, AATSR, ERS and RA-2
- SMOS and CryoSat
- Processing using 'drag and drop' or via the clipboard
- Export to ASCII (text/spreadsheets) via the Windows clipboard
Batch processing of image data
The latest version of Bilko also offers limited support for batch-processing of image data from the Windows Command line. This is based on Bilko sets (lists of files and parameters to be extracted from these) and formula documents (mini-programs) containing processing instructions. The batch processing capability is currently being tested by selected Bilko users.
Other free software
There are a number of free software packages available to process and manipulate data from ESA and other satellites. Some are more specialist than Bilko and suitable, for example, for more advanced processing of specific data types. Below we will add brief descriptions of these, with links to web sites where you can find the software and and user support for these packages.




