Survey Planning
Fugro-LCT have developed a survey planner to help you design
a survey layout. This will enable you to get an accurate estimate
of the total number of survey line kilometers for any given sail/flight
line and tie line separation. This information can then be used
to obtain a cost estimate or proposal for Fugro-LCT to undertake
the survey. To request a quote or for further information click
here.
For irregular shaped survey areas this planning applet allows
different sail/flight line orientations to be evaluated in order
to maximize efficiency of acquisition, usually achieved by having
the longest possible survey lines and minimizing line turns. However,
to allow effective processing of the data, lines must be of a
reasonable minimum length so that any short lines on the edge
of a survey may need to be extended beyond the survey boundary.
Fugro-LCT can advise on this requirement for any specific project.
If you experience any problems running this applet, it is likely
due to your firewall or browser configuration. Please check with
your system administrator and/or ensure that you have a Java-enabled
browser.
Launch survey
planner.
Geophysical Survey Design
If you have any comments or suggestions for this section please
mail them to infofri@fugro.com
Safety should be the main concern - features such as topography,
water depths, power lines etc. should be taken into
consideration when selecting acquisition parameters.
The prime line direction is commonly selected so that the lines
run perpendicular to the expected strike of the geology in
the survey area.
For gravity and magnetic surveys the line spacing should be
less than half the expected depth to the sources.
The tie line spacing is typically 4-5 times larger than the
prime line spacing.
In airborne surveys the flight height is determined by safety
factors and by the expected depth of geological targets.
Many shipborne potential field surveys will be done in conjunction
with a seismic survey. In these cases the survey geometry is defined
by the seismic program. However, the judicious addition of tie
lines (during transit or weather down time) can greatly improve
the overall robustness of the survey.
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Survey
coordinates
If the survey outline have been given to you as latitude and
longitude coordinates you will need to convert them to x,y positions.
If you have Fugro-LCT software installed on your system you can
use PROJPT, or GRDPRO to perform the calculations.
Click
here if you do not have access to projection software
The survey outline may have been specified using a local datum.
This may not be critical for a quick marketing proposal but may
be significant when actually performing the survey. Click
here to read an Introduction to Geodetic Datums It is best
if you keep the survey coordinates digitally in either an ASCII
file or in a word processor. As part of the Java Applet security
measures there is no way for the program to read a file directly
on your computer. Use your operating system's copy/paste function
to put the projected survey coordinates into the text area of
the survey planner.
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Defining Line Direction and Spacing
Enter the prime line and tie line directions in the relevant
boxes.. The prime and tie lines are commonly perpendicular to
one another with the prime lines running parallel to the dip of
the major geological structures in the survey area.
Enter prime and tie spacings. The distance units must be the
same as were used to define the survey outline.
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Starting the Computation
Press the "Compute" button and the program will compute
the actual navigation tracks. You can check the status area in
your web browser to see if the programming is operating correctly.
Once the program has finished it will display a map of the survey
area and report the length of the prime and tie lines. The lengths
will be in the same units as the survey polygon coordinates.
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Results
The bottom text area displays the start and end cooordinates
of each of the survey lines. Java Applets cannot write to your
machine's disk so you will have to copy and paste the results
into a word processor or ASCII file. It would be nice to have
a print button but due to the security restrictions of JDK1.0
that is not possible. You can use a print screen function, or
on UNIX try the great xv program or failing that SunOS's snapshot.
If you need larger scale maps you can use the results in your
favorite mapping program.
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Trouble shooting
[Q] My polygon does not look right.
[A] In Netscape (and maybe other browsers?) you can select Options/Show
Java Console. Look in this dialog box to check that your survey
outline points were read in correctly. The program expects blank
sperated fields.
[Q] How do I exclude an island/platform from the middle of my
marine survey?
[A] The program can handle key hole polygons - though at the moment
the resulting survey lines will be split into two. For an example
click here .
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Warranty
FUGRO-LCT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING,
WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE SURVEY PLANNING
APPLET. FUGRO-LCT DOES NOT WARRANT, GUARANTEE, OR MAKE ANY REPRESENTATIONS
REGARDING THE USE OR THE RESULTS OF THE USE OF THE SURVEY PLANNING
APPLET IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY, CURRENTNESS
OR OTHERWISE. YOU, THE END USER (OR YOUR EMPLOYER OR ANOTHER THIRD
PARTY AUTHORIZED TO PERMIT YOUR USE OF THE SURVEY PLANNING APPLET)
WILL ASSUME THE ENTIRE RISK FOR THE PERFORMANCE AND RESULTS OF
THE SURVEY PLANNING APPLET.
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