Level 1 Advanced Land Observing Satellite (ALOS) Phased Array type-L band Synthetic Aperture Radar (PALSAR) data were acquired from ESA by the Landmap project and processed to produce greyscale 8 and 32-bit geotiff imagery for the UK and Republic of Ireland from 2007-2009. The UK data are projected onto the British National Grid whereas the Republic of Ireland data are projected onto the Irish National Grid.

PALSAR is an active microwave sensor using L-band (2GHz) frequency and produces various products of different resolutions and performance. PALSAR data can be acquired during day or night, increasing the temporal coverage of data for a particular spatial extent. PALSAR is also unaffected by cloud cover allowing a better coverage of satellite data. PALSAR collects data in 4 different modes, with the following 3 available:

• Fine Beam Single (FBS) Mode: High resolution fine beam data that only acquires one polarisation product (horizontal transmit, horizontal receive (HH))
• Fine Beam Dual (FBD) Mode: High resolution fine beam data that acquires two types of polarisation products (horizontal transmit, horizontal receive (HH) and horizontal transmit, vertical receive (HV); or vertical transmit, vertical receive (VV) and vertical transmit, horizontal receive (VH))
• Polarimetric: Polarimetric data acquires all polarisation products (HH, HV, VH, and VV), however it does have a lower resolution than the fine beam modes.

The Joint Information Systems Committee (JISC) funded Landmap service which ran from 2001 to July 2014 collected and hosted a large amount of earth observation data for the majority of the UK. After removal of JISC funding in 2013, the Landmap service is no longer operational, with the data now held at the NEODC.

The PALSAR data are available to UK academics and students. To apply for access, please

1. Register as a NEODC user. If you already are a NEODC registered user, skip this step. If you have forgotten your NEODC user ID and/or password, please contact the NEODC helpdesk at neodc@rl.ac.uk.
2. Apply for access to the Landmap data. Application involves the agreement with the Landmap terms of use.

The data are available in geotiff format which can be opened in many earth observation image processing software including open/free software such as Erdas ER viewer and the freely available Basic ERS & Envisat (A)ATSR and Meris Toolbox (BEAM) or NEST (Next ESA SAR Toolbox). Geotiff files are TIFF files which have geographic metadata embedded as tags within the TIFF file. The geographic metadata can then be used to position the image in the correct location and geometry on the screen of a geographic information display. The data are split into the three modes acquired by Landmap (Fine Beam Single (FBS), Fine Beam Dual (FBD) and Polarimetric). The various polarisations can be determined from the filename:

• HH - Horizontal polarisation transmitted, horizontal received.
• VV - Vertical transmitted, vertical received
• HV - Horizontal transmitted, vertical received
• VH - Vertical transmitted, horizontal received

Software

Erdas ER viewer, available free of charge, can be used to open raster image formats such as TIFF, GeoTiff, IMG, ECW, ERS, ALG, DAT and many more, and is capable of handling large file sizes.

Basic ERS & Envisat (A) ATSR and Meris Toolbox (BEAM): BEAM is an open-source toolbox and development platform for viewing, analysing and processing of remote sensing raster data. Originally developed to facilitate the utilisation of image data from Envisat's optical instruments, BEAM now supports a growing number of other raster data formats such as GeoTIFF and NetCDF as well as data formats of other Earth Observation (EO) sensors such as Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer (AVHRR), AVNIR, Polarised Radiation Imaging and Spectroscopy Mission (PRISM) and Compact High Resolution Imaging Spectrometer (CHRIS). Various data and algorithms are supported by dedicated extension plug-ins.

NEST (Next ESA SAR Toolbox) is an ESA open source toolbox under the GNU GPL license for reading, processing, analysing and visualising ESA (ERS-1/2, ENVISAT, SENTINEL-1) and other spaceborne SAR data (TerraSAR-X, RADARSAT 1-2, COSMO-SkyMed, JERS-1, ALOS PALSAR) processed to Level-1 or higher.

Links to further information

• The Landmap project PALSAR website, this site may be offline soon after 1st August 2014 due to removal of JISC (Joint Information Systems Committee) funding, see below for an archived version of ths site
• An archived version of the site, hosted by the Internet Archive project
• The ESA PALSAR website
• Japan Aerospace Exploration Agency (JAXA) website on ALOS PALSAR
• Information on ALOS PALSAR products