=========================================== 
README  : Malå Geoscience RAMAC™ GPR example data
Author  : John Maurer (john-maurer@users.sourceforge.net)
          ©2005-2006 University of Colorado
Date    : April 5, 2006
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An example Malå Geoscience RAMAC™ (http://ramac.malags.com) ground-penetrating
radar (GPR) data file is provided in this directory to help the user become
familiar with the provided GPR IDL and ENVI software package. Each RAMAC
(http://ramac.malags.com) data file has several associated files with the same
base filename and different filename extensions (i.e. suffixes). In addition,
versions of the file that were processed using our software package in ENVI
are also provided herein. The different example files provided in this
directory are described below.

This example data file was collected in the northeast of the Greenland ice
sheet near the Tunu-N automatic weather station (AWS) (78°01'01" N, 33°58'54"
W; 2113 m a.s.l.) on 31 May 2003. It is about 5 m in depth and 120 m in
distance, including two 10-m transects followed by one 100-m transect (with
narrow, pale grey regions between these transects when the instrument was at
rest). This file was collected with a 1000-MHz antenna (the highest frequency
antenna offered for the RAMAC GPR), housed and pulled in a plastic sled at a
constant walking speed. Sixteen consecutive traces were stacked together
during data acquisition to reduce noise in the horizontal (areal) direction.
The instrument transmitted pulses at a rate of 24081 MHz, collecting 1024
discrete samples per trace over a two-way time window of 42.5 nanoseconds. The
data therefore have high vertical (depth) resolution of ~5 mm, well within the
width of stratigraphic layers. Using an average dry snow density of 0.3
g·cm^-3 measured manually at a nearby snow pit and an empirically derived
relative dielectric permittivity of 1.62 (Mätzler, 1996), maximum penetration
depth of the GPR signal at 1000-MHz over a 42.5 ns two-way time window was
about five meters. Within these five meters, one or two stratigraphic layers
can be visually identified within the data after filtering. For more details
regarding the motivation and results of this study can be found at:

http://cires.colorado.edu/~maurerj/gpr/gpr_cryosphere.html

Here is a listing and description of the files provided in this directory:
 
1. example_data.rd3

Files ending in *.rd3 are the raw RAMAC GPR data. These are 16-bit binary data
files that can be automatically opened and viewed in Malå Geoscience Ground
Vision software (http://www.malags.com/software/#groundvision). They can also
be automatically opened in ENVI software using the "open_ramac_gpr_file.pro"
IDL procedure provided in this software package.

2. example_data.rad

Files ending in *.rad are the RAMAC GPR header files associated with the raw
data. These text files contain important information about the data and are
also necessary in order to view the data in Ground Vision. Each line contains
one "parameter:value" pair. For definitions of the parameters listed in the
*.rad file and their associated units of measurement, refer to the RAMAC
Ground Vision Software Manual (although the documentation in this regard is
not very explicit, unfortunately). If files are to be copied to or from
another computer or disc, it is important that both the data file (*.rd3) and
the header file (*.rad) are copied.

3. example_data.cor

Files ending in *.cor are the RAMAC geographic coordinates associated with
each trace (i.e. horizontal-/x- dimension) of the RAMAC GPR data file,
collected via GPS during data collection. The seven (7) comma-delimited
columns within the *.cor file are:

a. trace # (pixel number in the horizontal-/x- dimension, starting with 1)
b. date (yyyy-m-d) (ex. 2003-5-31)
c. time (UTC)(h:m:s) (ex. 17:47:13)
d. latitude (ex. 78:01:00.42 NN)
e. longitude (ex. 33:58:50.96 WW)
f. height above mean-sea-level (m) (ex. 2120.000977M)
g. lat/long accuracy (m) (ex. 1.580057)

This file may or may not have been collected with a RAMAC GPR survey depending
on whether a GPS unit was used to acquire geographic coordinates during data
collection or not.

4. example_data.fil

Saved filter parameters in Ground Vision. When viewing the data in Ground
Vision, you can select to "Load list" from the filter menu and select the
*.fil file of choice. When viewing data in Ground Vision, you can also select
to "Save list" when you have properly filtered the data for viewing.

5. example_data.bin

The original "example_data.rd3" RAMAC GPR data file rotated 90 degrees so that
it is properly oriented when viewing in ENVI; this has been automatically
applied to the .rd3 file using "open_ramac_gpr_file.pro" and then saved to
this file. The "*.bin" extension is used to signify that it is a binary data
file. Because the data have been rotated, they are no longer viewable in
Ground Vision, which is why the "*.rd3" filename extension is not used.
  
6. example_data.hdr

ENVI header file necessary for opening "example_data.bin" in ENVI. Note that
the "open_ramac_gpr_file.pro" IDL procedure produced this ENVI header
automatically and provided a useful description.

7. example_data.jpg

A compressed image file of "example_data.bin" in JPEG format.

8. example_data_filtered.bin

A filtered version of "example_data.bin" using GPR filters provided in this
software package that optimizes the visibility of the GPR data for identifying
reflection horizons, or layers. 

9. example_data_filtered.hdr

ENVI header file necessary for opening "example_data_filtered.bin" in ENVI.
Note that the filters in this software package automatically provide details
in the description about the selected filters and their selected parameters
for subsequent reference.

10. example_data_filtered.roi

An ENVI polyline Region Of Interest (ROI) file that records the location of a
particular stratigraphic layer within the GPR data. This ROI was created by
hand using the mouse pointer and ENVI's ROI tool for tracing over the layer.
Note that there are many echoes of this layer in the data file, which is
common in GPR.

11. example_data_filtered.jpg

A compressed image file of "example_data_filtered.bin" in JPEG format with the
ENVI polyline Region Of Interest (ROI) layer ("example_data_filtered.roi") in
red.

============================================================================
John Maurer
M.A. - Department of Geography
Cooperative Institute for Research in Environmental Sciences (CIRES)
University of Colorado at Boulder
john-maurer@users.sourceforge.net
http://cires.colorado.edu/~maurerj
Advisor: Dr. Konrad Steffen (konrad.steffen@colorado.edu)
http://cires.colorado.edu/science/groups/steffen/
©2005-2006 University of Colorado