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| geoscene3d:qc_and_statistics:3dgridhistogram [2021/07/16 08:24] – linda_jacobsen | geoscene3d:qc_and_statistics:3dgridhistogram [2021/07/29 14:52] (current) – external edit 127.0.0.1 |
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| ====== 3D Grid Histogram ====== | ====== 3D Grid Histogram ====== |
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| //This tutorial shows how to quality check data by making histograms. The histogram can be used as a tool to gain a data overview before model building but the histogram is also useful for checking correct correlation between different datasets. Thus, it is a useful tool for analyzation both before and after model building. // | This tutorial shows how to quality check data by making histograms. The histogram can be used as a tool to gain a data overview before model building but the histogram is also useful for checking correct correlation between different datasets. Thus, it is a useful tool for analyzation both before and after model building. |
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| **__Requirements: __ ** | **__Requirements: __ ** |
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| * Voxel model with 3D grid | * A project with 3D grid |
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| ---- | ---- |
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| ==== Step 1. Floating value 3D Grid histogram ==== | ==== Option 1. Floating value 3D Grid histogram ==== |
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| * To make histograms a voxel model is needed. | * The trends of a dataset can be visualized and analyzed using the histogram, which shows the amount of voxels for different values in the dataset e.g. for resistivities. |
| * The biggest trends of a dataset can be visualized and analyzed in the histogram before a model is made by showing the amount of present voxels for different values in the dataset e.g. for resistivities. | |
| * Also, 1D models can be interpolated into 3D grids with the aim to check if data are corresponding e.g. to resistivities. | * Also, 1D models can be interpolated into 3D grids with the aim to check if data are corresponding e.g. to resistivities. |
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| {{:geoscene3d:qc_and_statistics:voxelmodel.png?nolink&}} | {{:geoscene3d:qc_and_statistics:voxelmodel.png?nolink&}} |
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| 1. "QC and Statistics" menu –> next –> "Calculation Mode" –> Floating value 3D Grid (e.g. Resistivities) –> "Input Data" –> your 3D grid –> next. | 1. "QC and Statistics" menu <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> next –> "Calculation Mode" <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> Floating value 3D Grid (e.g. Resistivities) <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> "Input Data" <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> your 3D grid <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> next. |
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| {{:geoscene3d:qc_and_statistics:grid_inputdata.png?nolink&}} | {{:geoscene3d:qc_and_statistics:grid_inputdata.png?nolink&}} |
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| 2. Choose the surfaces for where the calculation is needed by clicking the upper and lower constraint –> next. | 2. You can choose the surfaces for where the calculation is needed by clicking the upper and lower constraint <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> next. |
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| | * It can also be avoided to pick constraints if a histogram of the entire dataset is wanted. |
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| {{:geoscene3d:qc_and_statistics:calculation_constraints.png}} | {{:geoscene3d:qc_and_statistics:calculation_constraints.png}} |
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| * In the following picure the axis values has been fitted to the datapoints. | * In the following picure the axis values has been fitted to the datapoints. |
| * Notice how the bin size can be edited. Here, e.g. there are 65.000 voxels in the resistivity interval [30;40]. | * Notice how the x-axis can be edited. Here, e.g. there are 65.000 voxels in the resistivity interval [30;40]. |
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| {{:geoscene3d:qc_and_statistics:histogram_binsize10.png?nolink&}} | {{:geoscene3d:qc_and_statistics:histogram_binsize10.png?nolink&}} |
| {{:geoscene3d:qc_and_statistics:histogram_binsize20.png}} | {{:geoscene3d:qc_and_statistics:histogram_binsize20.png}} |
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| ==== Step 2. Discrete value 3D Grid histogram ==== | ==== Option 2. Discrete value 3D Grid histogram ==== |
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| * Discrete values e.g. chemistry values or lithologies. | * Discrete values e.g. chemistry values or lithologies. |
| 1. Repeat step 1.1. but choose "Discrete value 3D Grid (e.g. Lithologies)". | 1. Repeat step 1.1. but choose "Discrete value 3D Grid (e.g. Lithologies)". |
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| 2. Pick the discrete value for the histogram in "Discrete Value 3D Grid". Here lithology is chosen. | 2. Select a discrete 3D grid for the histogram in "Discrete Value 3D Grid". Here lithology is chosen. |
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| 3. Repeat step 1.2. for constraints. | 3. Repeat step 1.2. for constraints. |
| {{:geoscene3d:qc_and_statistics:lithology_histogram.png}} | {{:geoscene3d:qc_and_statistics:lithology_histogram.png}} |
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| 4. To show the lithology legend go to Object Manager –> rightclick lithology –> show legend. | 4. To show the lithology legend go to Object Manager <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> right click Lithology <font 11pt color font-weight: inherit; background-color; color: inherit; background-color: inherit background-color: inherit /Arial,Helvetica,sans-serif;;inherit;;inherit background-color: inherit background-color: inherit >→</font> Show Legend. |
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| {{:geoscene3d:qc_and_statistics:lithology.png}} | {{:geoscene3d:qc_and_statistics:lithology.png}} |
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| ==== Step 3. Combination of floating and discrete values ==== | ==== Option 3. Combination of floating and discrete values ==== |
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| * This tool is used to check e.g. if your resistivity data matches the concerned lithology. | * This tool is used to check e.g. if your resistivity data matches lithology. |
| * In this histogram setting the resistivities are held together with the lithology at the same voxel position. | * The resistivities are held together with the lithology grid at the same voxel position. |
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| you get the resisivities in the 3d grid at the same position as specific matching lithology grid values. | 1. Repeat step 1.1. and pick the floating and discrete values that you want to compare. |
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| picture: click and next. After define constraints like before. | * All lithologies can be picked for comparison with the resistivities but they can also be picked one by one. |
| | * This can be beneficial when specific lithologies can be connected to certain resistivites especially if the lithologies are very different. |
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| | 2. Repeat step 1.2. with defined constraints. |
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| {{:geoscene3d:qc_and_statistics:addcombined_lithology1.png?nolink&}} | {{:geoscene3d:qc_and_statistics:addcombined_lithology1.png?nolink&}} |
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| Histogram. Are the resistivities matching/corresponding the specific lithology chosen? | * A histogram with only one chosen lithology held together with resistivites. It shows the resisistivities where the lithology is ML (till) |
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| {{:geoscene3d:qc_and_statistics:histogram_layer1_binsize10_2.png?nolink&}} | {{:geoscene3d:qc_and_statistics:histogram_layer1_binsize10_2.png?nolink&}} |
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| To improve the details of the resistivity in the chosen lithology, the bin size can be reduced e.g. from 10 to 2. | |
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| {{:geoscene3d:qc_and_statistics:histogram_layer1_binsize2.png}} | |
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| * In previous picture the resistivities are mainly focused around [20;100] ohm*m whereas almost no datapoints are registered after around 150ohm*m. | |
| * The lithology ML (glacial moræneler/leret till = glacial morraine clay) can be expected to withhold low resistivity values and the histogram confirms the expectation. Although, it is distinct that the histogram holds two prominent peaks. | |
| * This peaks need attention. If the voxel counts for the peaks were abnormal and high in the resistivity values for ML something wrong in either the lithology, resistivity values or something that is not in sync. | |
| * | |
| * in the interpretation of the dataset could be errorneous. | |
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