1.2.1 Software Tools ASAR products are delivered in the
standard ENVISAT data format. Having received the
data, the following categories of software tools can
be used to explore ASAR products (see index)
188.8.131.52 General Software Tools Users may wish to directly decode
data in the ENVISAT format themselves, to allow
subsequent visualisation and further processing
in languages such as C, or in commonly
available software packages such as IDL, ENVI
and Erdas Imagine.
The EnviView tool,
which is discussed in detail in the ENVISAT
Handbook, can also be used to convert
ENVISAT data into hdf files. As briefly
discussed in the next section, "EnviView," 184.108.40.206. this
ENVISAT tool is not intended for the
detailed analysis, visualisation, and
processing of ENVISAT data. Other commercial
and proprietary tools provide these
facilities in great detail and with many
specialised options. The difference between
such tools and EnviView is that they are
usually aimed at certain classes of
data, such as images or atmospheric data, or
even data for a particular instrument.
EnviView, however, is a single solution
for all ENVISAT products. EnviView is
intended as a stepping stone between these
tools and the proprietary data format used
for ENVISAT data. The data can then be
automatically read by any software
supporting this format.
Some other tools that may be used for more
detailed analysis are provided below. Some
are not ASAR specific.
- IDL (Interactive Data Language)
http://www.rsinc.com a general purpose
graphical and scientific computing system
- CAESAR image processing (speckle
reduction) from NAS Software at http://www.nasoftware.co.uk
- DORIS Insar software (open-source) at http://www.geo.tudelft.nl/fmr/research/insar/sw/doris/index.html.cgi
- Earthview InSAR from PGI Geomatics at http://www.pcigeomatics.com
- ENVI from Research Systems at
http://www.rsinc.com based on the IDL product
- ERS SAR toolbox described at
and available at http://earth.esa.int/STBX/
- GAMMA http://www.gamma-rs.ch sells
modular SAR processor software, and
interferometric SAR and differential SAR processors
- GEOimage http://www.geoimage.fr software
for processing Earth-observation imagery
- Geomatica (remote-sensing image
processing, cartography, photogrammetry) http://www.pcigeomatics.com
- IMAGINE Professional (remote sensing
scene analysis, radar analysis, mapping) http://www.erdas.com
- Matlab http://www.mathworks.com includes
a number of optional toolboxes including
Signal Processing, System
Identification, Fuzzy Logic, Image
Processing, Mapping, Neural Networks.
- Mathematica http://www.wolfram.com/
- Noesys (data exploration and
visualisation) from Research Systems http://www.rsinc.com
- PulSAR from Phoenix Systems, http://www.phoenixsystems.co.uk
- PV-WAVE http://www.vni.com data
manipulation, visualisation, statistics.
Image Processing and Signal Processing
- SARscape http://www.sarmap.ch
220.127.116.11 EnviView The EnviView tool, developed by
ESA, is described in detail in the ENVISAT
Handbook. In general, however, EnviView is a
tool capable of opening and decoding data in
a format exclusive to the ENVISAT Ground
Segment, known as Payload Data Segment (PDS)
format. It then displays the data as simple
text in HTML format, as graphs, or as images
when these are appropriate.
As with the
data from all of the ENVISAT instruments,
the EnviView is a simple tool to provide a
first look at ASAR data files in the PDS
format. It uses a graphical user interface
for data exploration and visualisations and
is intended for the following purposes:
- To be able to open any Level 0, 1b,
Level 2 or auxiliary PDS data file.
- To determine and display the contents of
a file and the value of any given fields
in any data set, except raw source
packets (level 0 data).
- To provide basic visualisation of data
through simple 2D graphs and images.
- To visualise certain high level
data sets in a meaningful manner where a
2D graph conveys little information,especially:
- ASAR image data sets
- ASAR Wave spectra.
- To provide a representation of the
geographic coverage on a rectangular map projection.
- To export selected data to HDF, ASCII or
binary data files, for analysis in COTS
tools such as Mathematica, IDL, Excel,
and so on..
- To save the contents of a record as HTML
text for inclusion in reports.
- To provide support for printing and
system clipboard (cut/paste)where possible.
- To be highly portable and to reach as
wide an audience as possible.
- To be guaranteed to run on Unix,Windows
and MacOS and potentially other
|Figure 1.101 Example of Level 1B Wave Product Cross Spectra
Figure1.101 is an example of a
level 1b wave product, as seen using the
EnviView ASAR Wave Spectra View window. (See
section entitled Wave Spectra 18.104.22.168. ). A
wave spectrum viewer displays a false colour
polar plot showing level 1B or level 2 ASAR
wave spectra data. Since the data values
are complex, having both real and imaginary
parts, various representations of the
spectra are possible. Data from one record
at a time is displayed with the option
of displaying record data sequentially as a movie.
The ASAR level 1B wave spectrum
data is complex, containing both real and
imaginary parts. EnviView only displays
scalar (1 dimensional) values on the
ASAR wave spectrum viewer, which means that
it can only display either the real parts,
the imaginary parts, or some scalar
combination of the real and imaginary parts.
ASAR Level 2 data is not
complex, hence there is no need to have
selection provided for different display
types when viewing such a data set.
Level 2 data is neither symmetric nor
anti-symmetric, and contains information for
the entire 360 spectrum.
The complete instructions for
the use and application of the EnviView
viewer are provided in the EnviView User
Guide that is included with the viewer
when it is delivered to the customer.
22.214.171.124 ASAR Toolbox
The Basic Envisat SAR Toolbox (BEST) is a
collection of executable
software tools that has been designed to
facilitate the use of ESA SAR data. The
purpose of the Toolbox is not
to duplicate existing commercial packages,
but to complement them with functions
dedicated to the handling of SAR
products obtained from ASAR (Advanced
Synthetic Aperture Radar) and AMI (Active
Microwave Instrument) onboard
Envisat and ERS 1&2 respectively.
The Toolbox operates according to
user-generated parameter files.
The software is designed with an optional
graphical interface that
simplifies specification of the required
processing parameters for each tool and (for
Windows versions only) sets it
running. The interface doesn't
include a display function. However, it includes
a facility to convert images to TIFF or
GeoTIFF format so that they can be read
by many commonly available visualisation
tools. Data may also be exported in the BIL
format for ingestion into other image
processing software, and the tools may
be integrated within (for example) IDL.
tools are designed to achieve
the following functions:
Data Import and Quick
of quick-look and full resolution
internal format files
from a variety of ESA SAR products and
import of TIFF and
GeoTIFF images and generic raster data.
Data Export: output of
data to selected common
formats (TIFF, Geo TIFF and BIL).
different image formats (e.g. power
to amplitude) and
transformation of the data by flipping
or slant range to ground
calculation of global or
local statistical parameters from
real image data and
computation of the principal components
of multiple images.
Resampling: over- and under- sampling
of an image by means of spatial and
Co-registration and Coherence
both real and complex images,
interferometric coherence and
application of automatic geo-correction.
improvement of the radiometric
resolution of a
radiometric correction of
an input image to a variety of
The Toolbox has been designed to handle ESA
data products from both the
Envisat ASAR instrument and the AMIs on
ASAR data acquired in Image Mode, Wide Swath
Mode, Alternating Polarisation
Mode and Global Monitoring Mode,
processed to Level 0 or Level 1b (SLC,
Precision, Medium Resolution
or Ellipsoid Geo-coded), is supported.
Image Data from ERS SAR, processed as RAW,
SLC, SLCI, PRI, GEC or GTC, is
The Toolbox handles the standard Envisat
product file format. For ERS
data, products generated within the ESA
ERS ground segment at D-PAF,
I-PAF, UK-PAF and ESRIN are
supported, plus data from non-ESA PAF
stations, if they are delivered
with ESA CEOS annotations.
More information is available from the
envisat web site at http://envisat.esa.int/best