Salve a tutti,
ho un dubbio da risolvere e chiedo il vostro aiuto..nello specifico mi rivolgo all'utilizzo di Rayfract, perchè uso quello, ma è una domanda di carattere generale per tutti i software.
Il dubbio è relativo all'elaborazione di una tomografia sismica a rifrazione con elevato dislivello topografico, ad esempio perche eseguita su un versante in frana.
Nell'inserimento della geometria della stesa, ovvero del posizionamento dei geofoni, devo inserire il posizionamento nominale dei geofoni (ad esempio se eseguito a 24 canali con spaziatura 5 m, verrebbe 23 X 5= 115 m)oppure poiche c'è una elevata pendenza devo inserire nell'asse delle X dei Geofoni la reale distanza in pianta tra geofoni che ovviamente non sarà piu di 5 m, poiche tale misura è stata presa lungo la superficie topografica inclinata.
Premetto che ogni punto geofonico è stato correttamente preso con GPS, quindi ho il modo di sapere quale la distanza in pianta sull'asse delle X tra ogni geofono e la quota Z.
La domanda è anche concettuale cioè se i software di elaborazione, in questo caso Rayfract, accettano geometrie sull'asse delle X variabili, oppure se la distanza deve rimanere sempre la stessa, per motivi di algoritmo di calcolo.
Spero di essere stato chiaro nella domanda.
Un saluto a tutti e grazie per l'aiuto.

I recommend exporting coordinates to .COR file format :

- select File|Export header data|Export Station Coordinates...
- click Save button to save to COORDS.COR file
- see our .pdf reference

http://rayfract.com/help/rayfract.pdf

chapter File formats on page 192 :

FILE FORMATS .................................................................................................................... 192
STATION COORDINATE FILES ................................................................................................. 192
SHOTPOINT COORDINATE FILES............................................................................................. 194
FIRST BREAK FILES ............................................................................................................... 197
ASCII.ASC FILES................................................................................................................. 199
.CSV LAYERED MODEL FILE .................................................................................................. 201
CONVERT .CSV LAYER MODEL TO SURFER .GRD LAYERED STARTING MODEL ......................... 202
.HDR BATCH FILE ................................................................................................................ 203
CONVERT SURFER .GRD FILE TO ASCII .TXT WITH X/Y/Z/VELOCITY FOR EACH GRID CELL ....... 206

Next e.g. import the COORDS.COR into Microsoft Excel and edit the x/y/z columns (columns 2/3/4). Leave column no. 1 (station no.) unchanged.

Next export in Excel to updated MYCOORDS.COR .

Now select our File|Update header data|Update Station Coordinates... and your updated MYCOORDS.COR .

Check updated coordinates in Header|Station .

We regard station z values when plotting the tomogram topography.

Our horizontal axis is "horizontal inline offset" from profile's first receiver.

Check option File|Export data Settings|Export horizontal inline offset and v0 to .COR .

Reexport updated coordinates to GOOD.COR .

Now open GOOD.COR e.g. with Windows Notepad editor . We list the "horizontal inline offset" in m in column no. 4 .

For layered refraction methods (Plus-Minus, Wavefront) we assume that receivers are planted at whole station numbers specified for the Spread type used to import your shots in File|Import Data .

For 2D WET inversion we regard the true x/y/z coordinates specified in Header|Station.

Should say "We list the 'horizontal inline offset' in m in column no. 5" not column no. 4.

Our new tutorial

http://rayfract.com/tutorials/1_1D.pdf

shows multiscale Conjugate-Gradient WET inversion of synthetic data for subsurface model with 3 vertical fault zones (NGU 2018) using our DeltatV+XTV starting model.

NGU 2018 report by Georgios Tassis et al. is available at

http://www.ngu.no/upload/Publikasjoner/Rapporter/2018/2018_015.pdf

For updated green WibuKey driver instructions see

http://rayfract.com/help/Uninstall%20&%20reinstall%20WibuKey%206.40.pdf

For installation of our software version 3.35/3.36 under Windows 10 64-bit Oct 2018 update see

http://rayfract.com/help/install3.36.pdf

We compiled our latest version 3.36 software with Microsoft Visual C++14 in Visual Studio 17.

WET inversion now runs up to 25% faster than with our version 3.35.

Our version 3.36 works fine in Windows 10, Windows 7 Pro and Windows XP SP3.

For latest release notes see

http://rayfract.com/help/release_notes.pdf .

Our latest tutorial

http://rayfract.com/tutorials/TYLERLN1_2019.pdf

shows karst imaging for a line which we interpreted in 2006 already. Also we link to GeoTomo LLC interpretation which has been published and is similar to our output. See

https://www.slideshare.net/oncel/sinkhole-geophysics

For an objective comparison of available refraction tomography software see

http://rayfract.com/pub/Zelt_etal_JEEG.pdf

For our latest release notes see

http://rayfract.com/help/release_notes.pdf

We now better support importing of streamer-recorded SEG-2 formatted data with custom/irregular spacing of traces. Also we import true x/y/z coordinates specified in the SEG-2 trace headers.

Our latest tutorial

http://rayfract.com/tutorials/P6.pdf

shows fracture zone detection in bedrock. We use Smooth inversion & 100 WET iterations with full WET smoothing with 1D-gradient & layered Plus-Minus starting models.

We show how to visualize the dipping fault zone in Common Mid-Point (CMP) display and Common Offset display of your raw first break picks. These displays show the raw traveltime data before running any inversion.

Also we show batch import of SEG-2 files with bad recording geometry specified in SOURCE_LOCATION and RECEIVER_LOCATION trace headers.

For latest release notes see

http://rayfract.com/help/release_notes.pdf

We have updated our tutorial

https://rayfract.com/tutorials/ot0608.pdf

to show 20 Steepest-Descent WET iterations with laterally averaged 1D-gradient starting model (Sheehan, 2005) and with Wavelength-Dependent Velocity Smoothing (WDVS; Zelt and Chen 2016) enabled at 90Hz. We discard WET smoothing after forward modelling to improve the WET resolution.

We use default Smooth inversion settings and default DeltatV settings to obtain the default 1D-gradient starting model. Also we use minimal WET smoothing and blank no coverage after last WET iteration.

For latest release notes see

https://rayfract.com/help/release_notes.pdf

Our new tutorial shows imaging of strongly weathered granitic basement with thick overburden in NSW Australia. See

https://rayfract.com/tutorials/Test21.pdf

We show both 1D-gradient and pseudo-2D DeltatV starting models.

Also we use WDVS Smoothing @120Hz and minimal WET smoothing.

We lower the WET wavepath frequency from default 50Hz to 30Hz for wider wavepaths and deeper imaging.

Also we show import of DMT SUMMIT X SEG-2 files.

For latest release notes see

https://rayfract.com/help/release_notes.pdf