Roll is a plugin aimed at designing 3D seismic survey geometries, using a template based approach.
- Each survey consists of one or more (rectangular) blocks
- Each block contains at least two templates
- One for receiver layout
- One for source layout
- Each template contains one or more seeds
- A seed defines the starting location of a single source / receiver
- Each seed can be grown up to three times
- The 1st grow step changes a seed position into a line segment (sequence) of positions
- The 2nd grow step changes a line segment into a multitude (grid) of lines
- The 3rd grow step changes the grid into a sequence of (intertwined) grids
- The seeds, combined with their grow steps, define the active sources and receivers in a template
- Each template can be rolled in up to three directions, for instance:
- Firstly in the inline direction, at source line intervals
- Secondly in the crossline direction, at receiver line intervals
- Optionally at a skew angle for fancy designs
The hierarchy in this approach is reflected in the xml-based survey-file structure:
<block_list>
<block>
<name>Block-1</name>
<borders>
<src_border xmin="-20000.0" xmax="20000.0" ymin="-20000.0" ymax="20000.0"/>
<rec_border xmin="0.0" xmax="0.0" ymin="0.0" ymax="0.0"/>
</borders>
<template_list>
<template>
<name>Template-1</name>
<roll_list>
<translate n="10" dx="0.0" dy="200.0"/>
<translate n="10" dx="250.0" dy="0.0"/>
</roll_list>
<seed_list>
<seed x0="5975.0" src="True" y0="625.0" argb="#77ff0000" typno="0" azi="False" patno="0">
<name>Src-1</name>
<grow_list>
<translate n="1" dx="250.0" dy="0.0"/>
<translate n="4" dx="0.0" dy="50.0"/>
</grow_list>
</seed>
<seed x0="0.0" src="False" y0="0.0" argb="#7700b0f0" typno="0" azi="False" patno="1">
<name>Rec-1</name>
<grow_list>
<translate n="8" dx="0.0" dy="200.0"/>
<translate n="240" dx="50.0" dy="0.0"/>
</grow_list>
</seed>
</seed_list>
</template>
</template_list>
</block>
</block_list>Excerpt from a .roll file
Once the geometry has been defined, a binning analysis can be done directly using the template-based approach. As a result:
-
A fold map is created that shows (offset dependent) fold
-
A minimum offset map is created that shows minimum offsets coverage
-
A maximum offset map is created that show maximum offsets coverage
-
A RMS offset increment map is created that shows regularity of offset increments
As the survey project-file always contains a (projected) coordinate reference system (CRS) the analysis maps can be exported to the current QGIS project as a georeferenced Tiff (GeoTiff) file. These files can also be exported as a standalone GeoTiff file from the File -> Export menu.
To use full binning from the Processing menu, the project needs to be saved first, as a (large, memory mapped) analysis file is created that contains the complete binning information. Think of:
- line & stake numbers,
- src (x, y),
- rec(x, y),
- cmp(x, y),
- TWT,
- offset,
- azimuth, and
- uniqueness (for unique fold)
Once this step has been completed, additional analysis information becomes available in the Layout tab:
- An rms offset map that shows the rms offset increments in each bin (lower is better)
- A spider diagram, that is overlaid on the layout map, showing start- and end-points of all traces in a single (selected) bin
In the Analysis tab, the following information then becomes available:
- A trace table, showing the information from the analysis file
- Radial offsets shown for a line in the inline direction
- Radial offsets shown for a line in the x-line direction
- Source -> receiver azimuths shown for a line in the inline direction
- Source -> receiver azimuths shown for a line in the x-line direction
- Kr stack response shown for a line in the inline direction
- Kr stack response shown for a line in the x-line direction
- Kxy stack response shown for a single bin
- |Offset| histogram for all traces in the selected binning area
- Offset/azimuth histogram for all traces in the selected binning area, in steps of 5 degrees
The templates can be converted into geometry files, consisting of (a) a source file, (b) a receiver file and (c) a relation file, similar how this is managed in the SPS format. The source- and receiver points from the source and receiver files can be exported to the current QGIS project as an ArcGIS Shape file, where these points can be inspected, moved around or deleted. Edited points can be re-imported into Roll to assess the impact on fold, etc.
The geometry files themselves can also be exported as SPS-files.
Note: the Model/View approach used by Qt (that takes care of all the widgets in QGIS) allows for fairly large tables. Nevertheless, for each row in a table view, circa 12 bytes are allocated per row. For very large tables, QGIS will simply crash without any warning. As a result the GUI will 'hang' and you may lose all your work. For that reason, the trace table is currently limited to 50 million traces. Larger tables can still be used okay, they are just not shown in the trace table. If you need detailed information on traces that belong to a bin area somewhere in a large survey, the current work around is to select a smaller binning area, such that the total number of traces (Nx x Ny x Fold) is less than 50 million. A 'proper' solution is being worked on.
The plugin works best using one or two QHD Screens (2560 x 1440 pixels) or larger. As of QGIS V3.32 High DPI UI scaling issues have arisen. See the following discussion on GitHub here. The Help menu in Roll shows how you can mitigate against these issues.
As of version 3.34.6, QGIS upgraded Python from V3.9 to to V3.12 This change speeds up calculations and solves some security issues. But when upgrading from an earlier QGIS version, it requires installing all the dependencies again. See chapter 4 below for a list of external dependencies.
As of version 0.3.3 Roll has a 'working' interface with QGIS, and is able to read back points that have been changed in QGIS. This involves either moving points around, or setting a flag whether the point is in use. The integer Field Code that is used to decide whether a point is active or not can be selected in the Layer Selection Dialog. Points that are 'inactive' are shown in grey in the geometry tables and in the Layout view. They do not contribute is the fold (etc.) analysis.
The interface still requires a few tweaks, but as of version 3.3.3 Roll is no longer considered an experimental plugin.
If (legacy) SPS data is available, this can be imported from the file menu, and is treated the same as the internally generated geometry files. This makes it handy to analyze survey performance based solely on SPS-data. This SPS data can also be exported as shapefiles to the current QGIS project.
As there are many flavors of SPS files, a number varieties have been predefined, and can be selected from File -> Settings. The SPS-flavors are kept in a list of available Python dictionaries kept in config.py:
spsFormatList = [
# configuration settings for locations of fields in SPS data;
# all indices are 'zero' based and the last number is not included
# the first character is therefore [0, 1], the last one is [79, 80]
# Note: In SEG rev2.1, Point is followed by two spaces (Col 22-23 as per SPS 2.1 format)
dict(name='Netherlands', hdr='H', src='S', rec='R', rel='X', line=[11, 15], point=[21, 25], index=[25, 26], code=[26, 28], depth=[33, 37], east=[47, 55], north=[57, 65], elev=[65, 71]),
dict(name='New Zealand', hdr='H', src='S', rec='R', rel='X', line=[13, 17], point=[17, 21], index=[23, 24], code=[24, 26], depth=[30, 34], east=[47, 55], north=[57, 65], elev=[65, 71]),
dict(name='SEG rev2.1', hdr='H', src='S', rec='R', rel='X', line=[1, 12], point=[11, 21], index=[23, 24], code=[24, 25],depth=[30, 34],east=[46, 55],north=[55, 65],elev=[65, 71],),
]
xpsFormatList = [
# configuration settings for locations of fields in SPS data;
# all indices are 'zero' based and the last number is not included
# the first character is therefore [0, 1], the last one is [79, 80]
dict(name='Netherlands', hdr='H', src='S', rec='R', rel='X', record=[8, 11], srcLin=[23, 27], srcPnt=[33, 37], srcInd=[37, 38], recLin=[57, 61], recMin=[67, 71], recMax=[75, 79], recInd=[79, 80]),
dict(name='New Zealand', hdr='H', src='S', rec='R', rel='X', record=[8, 15], srcLin=[29, 33], srcPnt=[33, 37], srcInd=[37, 38], recLin=[61, 65], recMin=[65, 69], recMax=[75, 79], recInd=[79, 80]),
dict(name='SEG rev2.1', hdr='H', src='S', rec='R', rel='X', record=[7, 15], srcLin=[17, 27], srcPnt=[27, 37], srcInd=[37, 38], recLin=[49, 59], recMin=[59, 69], recMax=[69, 79], recInd=[79, 80]),
]Excerpt from the config.py file
The user can expand this list with new SPS 'flavors', by defining new 'point' and 'relational' record formats and store these in the config.py file.
As it is cumbersome to manipulate xml-data directly, the user is helped on two levels:
- Creating a new project can be done using a survey wizard. At present there is one wizard suitable to generate templates for land seismic and OBN-data. A marine wizard is in the making.
- Parameters can be modified added or deleted from the property pane. Behind the scenes, this updates the xml-structure, which is always visible from the Xml-tab in the main window.
But if you get familiar with the xml-structure, you could edit the xml data directly and apply any changes using the 'Refresh Document' toolbar button.
Roll depends on the following Python libraries that need to be installed separately
In the OSGeo4W Command Shell, type: pip install --upgrade 'library-name', where --upgrade forces the installation of the latest version
| Library | Minimum Version | Description (purpose) |
|---|---|---|
| numba | 0.59.1 | Significantly speed up some numpy calculations |
| numpy | 1.26.24 | Array and matrix manipulation |
| pyqtgraph | 0.13.4 | Plotting of vector and raster data |
| rasterio | 1.3.9 | Export of figures as GeoTiff files |
| wellpathpy | 0.5.0 | Handle sensors & sources in a well trajectory (VSPs etc.) |
On 8 Feb 2024, the first release of Roll has been published on GitHub. Initial release on the QGIS plugin website occurred on 13 March 2024.
As of version 3.3.3 Roll is no longer considered an experimental plugin. But there is still some functionality left to be added. See 'To Do' section.
Furthermore, see the 'Changelog' for already implemented functionality. Any Issues or pull requests can be raised through the GitHub repository.
- 2024-07/27 (0.3.4) "inuse" field added to src & rec points in QGIS. Categorized Symbol Renderer implemented to display used/unused points in QGIS.
- 2024-07/24 (0.3.3) Interface with QGIS improved. Display active / inactive points separately. Fixed rasterio CRS bug. Cleared experimental flag.
- 2024-07/08 (0.3.2) Geometry creation from templates now runs significantly faster. Fixed some bugs in Land Survey Wizard.
- 2024-06-02 (0.3.1) Created a 'display' menu. This allows for closing the display pane, when using smallish full HD displays. Fixed some bugs.
- 2024-05-27 (0.3.0) reduced minimal width of Geometry & SPS tables, in order to make working with a smallish full HD (1920x1080) screen easier.
- 2024-05-23 (0.2.9) expanded numba @jit functions, added rms-offset plot on Layout tab. Fixed some bugs. Implemented function profiling.
- 2024-05-04 (0.2.8) implemented numba @jit, to speed up calculations. Added stack-response analysis and |O| & O/A Histograms. Fixed some bugs.
- 2024-04-22 (0.2.7) removed all numba @jit references, as exception handling with numba causes problems. Will revisit later.
- 2024-04-21 (0.2.6) added 'Analysis' tab, containing:
- The Trace table (full binning results)
- In-/ and X-line offsets
- In-/ and X-line azimuths
- In-/ and X-line stack response
- 2024-04-13 (0.2.5) included TWT values in trace table and implemented 'Unique Fold' capability.
- 2024-04-08 (0.2.4) improved handling of well-files.
- 2024-03-30 (0.2.3) updated metadata.txt (a) about text and (b) dependencies.
- 2024-03-30 (0.2.2) improved handling of line- and stake numbers; refactoring of parameter handling.
- 2024-03-13 (0.2.1) Initial release on the QGIS plugin website.
- Improve handling of SPS data, and related to this, the interface with QGIS
- Make processing of Geometry & SPS data more robust
- Create wizard for Marine towed-streamer geometry
- Improve analysis capabilities
- Include Level Of Detail (LOD) settings in Read/Save settings to make them permanent
- Show pattern layout and add Kx-Ky pattern analysis
- Use multiprocessing instead of a worker thread to speed up background tasks
- Consider using a relational database instead of numpy arrays for geometry tables