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I get the error message: No write access on directory "/<xxxx>/.pf/"
When starting a module, a printfile containing log information, will automatically be created in a folder called .pf. If this is not possible, the error message is given. The .pf directory is located at the same level as the Home Directory in the select project dialog or in the environment variable SM_HOME. Check the access codes and the ownership of the .pf directory and set it readable and writeable for your user.
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All the modules exit as soon as they are started
- The read/write access of the .pf directory does not allow you to open a printfile. When starting a module, a printfile containing log information, will automatically be created. If this is not possible, the module willl exit. The .pf directory is situated at the same level as the Project Directory. Check the access codes and the ownership of the .pf directory and set it readable and writeable to your user.
- The X-server on your display-host may not authorize access from the remote host on which you are running the software. The reasons may be:
- Max number of X-clients are connected to your X-server. Exit some of the X-applications that are running.
- Client is not authorized to connect to server. Authorize the client with xhost +<remote host>
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How can I modify the NORSAR project directory setup?
The restart files for NORSAR-2D and NORSAR-3D containing the project directory paths can be found in the following files:
$HOME/.n2d/*, $HOME/.n3d/* and $HOME/.N23DProjectHomes.restart
These files can be edited or removed without losing any data.
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How to use a NORSAR-2D model in NORSAR-3D
The conversion consists of two steps:
- In NORSAR-2D, store the NORSAR-2D model on the Seismic Model Interchange File (.Smif) ASCII format.
- In NORSAR-3D, load the .Smif file and make a NORSAR-3D model.
There are two different ways to do this conversion:
- Method 1
You can always use this procedure, but it may in some cases change the global coordinates of the model. NORSAR-2D and NORSAR-3D may use different projects.
- Method 2
can only be used if the NORSAR-2D modeling Section is an Inline or Crossline section in the NORSAR-3D project. NORSAR-2D and NORSAR-3D must use the same project. The coordinates are retained.
Method 1
- From the NORSAR-2D Console Window select File > Export > SMIF Generator.
- Set a suitable output directory.
- Generate the .Smif model. It is stored as an ASCII file on the selected directory.
- From the NORSAR-3D Console Window select File > Import > Model Import > N2D Smif import.
- Set directory, select the .Smif file, and Convert.
- A cylindrical, 2.5D NORSAR-3D model is made. The 2D model varies in the x-direction in the model coordinate system. The model is invariant in the y-direction.
Method 2- From the NORSAR-2D Console Window select File > Export > SMIF Generator.
- Use the default output directory ‘./’.
- Generate the .Smif model. It is stored as an ASCII file on the selected directory.
- From the NORSAR-3D Console Window start Functions > Model > Model Builder.
- In the Model Builder, select File > Load > 2D model from Smif. Select the section-model combination and load.
- In the Model Builder, select 2DModels > 2.5D model from 2D. Select the section-model combination and make the 2.5D model.
- Select the model in the hierarchy window and in File > Store > Selected group/model as… store it ‘As model ready for ray-tracing’.
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Technical
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Traveltimes from 'free' diffraction points in NORSAR-2D
Diffraction modelling in N2D is restricted to 'diffractors' defined by physical edges in the intersection points between two interfaces in the model. In this case, algorithms are implemented which simulate traveltimes and amplitudes for diffracted events. The amplitudes will e. g. be dependent of how the two interfaces are oriented relative to the incoming and outgoing rays at the diffractor. However, some users have asked for the possibilities of defining 'free' diffraction points anywhere inside the model and to calculate traveltimes corresponding to these 'artificial diffractors'. There is currently no direct option for defining such 'non-physical' diffraction points, but some possible 'work-arounds' can be proposed:
- Halving the velocities in the model and put a shot point into the diffractor
- - external action for varying velocity grids
- - only zero offset modelling
- - no direct comparison with other reflected events
- + fast
- + traveltimes can be viewed within N2D
- Put a shot point into the diffractor
- - only zero offset modelling
- - no direct comparison with other reflected events
- - external action to double traveltimes
- - traveltimes have to be exported to be viewed
- + fast
- + no changes to the model necessary
- NIP tracer + triangle
- - creating a triangle in the model
- - only zero offset modelling
- + fast
- + direct comparison with other reflected events possible
- + traveltimes can be viewed within N2D
- CS/VSP tracer + triangle
- - creating a triangle in the model
- - slow
- + finite offset modelling possible
- + direct comparison with other reflected events possible
- + traveltimes can be viewed within N2D
- Halving the velocities in the model and put a shot point into the diffractor
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Does NORSAR-2D simulate 'head-waves' (refraction energy?)
The answer about modelling critical refraction is that the dynamic ray theory that we use in NORSAR-2D is not valid for so-called head-waves, that is, waves tied to critical refraction from a given interface.
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Modelling Project
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Easy guide for project definition
In the modelling project definition window enter the values in the sequence described in the window's help text, in section 2.5 'Easy guide on how...':
- Select Mapping rule 'Fixed Step'.
- Enter the inline and crossline indices. For each range first enter the 'To' value.
- Switch to Mapping rule 'Fixed Indices'.
- Enter the steps for inline index and for crossline index. Push 'Layout...', and set Crossline index Increase along local X-axis and Inline index Increase along local Y-axis.
- Switch to Mapping rule 'Fixed indices & Step'.
- Set local X and local Y. 'To' will automatically be adjusted to the inline-crossline range.
- Enter the (X,Y) or Inline/Crossline point and the corresponding X-UTM and Y-UTM point. Optionally enter the Grid Rotation angle.
- Push 'Plot coordinate system' to check the definition.
- OK or Apply.