{ "cells": [ { "cell_type": "markdown", "id": "9096dd16-2394-4d1b-bfda-7a869806df67", "metadata": {}, "source": [ "# Osborne Mine and Lightning Creek Sill Complex aeromagnetic data\n", "\n", "This is a section of a survey acquired in 1990 by the Queensland Government, Australia. The data are good quality with approximately 80 m terrain clearance and 200 m line spacing. The section contains the total field magnetic anomalies associated with the Osborne Mine, Lightning Creek sill complex, and the Brumby prospect. \n", "\n", "> **WARNING**: This notebook required \\~9 Gb of RAM to run. The dataset is a bit large (\\~3 Gb on disk and ~90 million points) and the GA provided netCDF file is not very useful for out-of-memory indexing since the latitude and longitude aren't properly set as coordinates. \n", "\n", "License: [CC-BY](http://pid.geoscience.gov.au/dataset/ga/142419)\n", "\n", "Original source: Geophysical Acquisition & Processing Section 2019. MIM Data from Mt Isa Inlier, QLD (P1029), magnetic line data, AWAGS levelled. Geoscience Australia, Canberra. http://pid.geoscience.gov.au/dataset/ga/142419\n", "\n", "Useful references for prior interpretations and geological context:\n", "\n", "* [Austin, et al. (2013)](https://doi.org/10.1190/INT-2013-0005.1)\n", "* [Gazley et al. (2016)](https://publications.csiro.au/rpr/download?pid=csiro:EP165511&dsid=DS2)\n", "* [Rezaie (2021)](https://doi.org/10.1007/s00024-021-02747-6)\n", "* [Elllis et al. (2019)](https://doi.org/10.1071/ASEG2012ab117)\n", "* [Perring et al. (2000)](https://doi.org/10.2113/gsecongeo.95.5.1067)" ] }, { "cell_type": "code", "execution_count": 1, "id": "0418f153-ff47-4318-b22f-02fb0774f42a", "metadata": {}, "outputs": [], "source": [ "import os\n", "import numpy as np\n", "import xarray as xr\n", "import pandas as pd\n", "import pygmt\n", "import pyproj\n", "import verde as vd\n", "import pooch" ] }, { "cell_type": "markdown", "id": "01752447-e620-409d-b9ca-80d3b72cd537", "metadata": {}, "source": [ "## Download the data archive\n", "\n", "Use Pooch to download the data archive provided by Geoscience Australia in netCDF format." ] }, { "cell_type": "code", "execution_count": 2, "id": "42e8b207-daac-43f3-be86-300adeb8e7e1", "metadata": {}, "outputs": [], "source": [ "fname = pooch.retrieve(\n", " url=\"http://dapds00.nci.org.au/thredds/fileServer/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/QLD/line/P1029/P1029-line-magnetic-AWAGS_MAG_2010.nc\",\n", " known_hash=\"sha256:119b472da05365f0df4e9dc0b2d4b0e5c213705acb4f79efcaa07e1aeeb7242c\",\n", ")" ] }, { "cell_type": "markdown", "id": "cc9b6e57-0912-4594-adf0-d46e818cd16b", "metadata": {}, "source": [ "Check the file size in Mb just so we know what we're dealing with." ] }, { "cell_type": "code", "execution_count": 3, "id": "a04c370e-f854-4d1b-8540-cae011ddf4fa", "metadata": {}, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "size: 3096.63 Mb\n" ] } ], "source": [ "print(f\"size: {os.path.getsize(fname) / 1e6 : 7.2f} Mb\")" ] }, { "cell_type": "markdown", "id": "7ec533d5-1719-46ce-b941-c191335b7f79", "metadata": {}, "source": [ "## Load the data\n", "\n", "That's around 3 Gb of data (likely compressed) so it's best to open the `xarray.Dataset` without reading everything into memory at once (as `xarray.load_dataset` would do)." ] }, { "cell_type": "code", "execution_count": 4, "id": "bc789b5e-49e6-485f-8dce-eee7697799ac", "metadata": {}, "outputs": [ { "data": { "text/html": [ "
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\n", " | longitude | \n", "latitude | \n", "terrain_clearance_m | \n", "total_field_anomaly_nt | \n", "flight_line | \n", "
---|---|---|---|---|---|
0 | \n", "140.664104 | \n", "-21.868339 | \n", "80.699997 | \n", "-124.284653 | \n", "5576 | \n", "
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3 | \n", "140.663847 | \n", "-21.868338 | \n", "80.500000 | \n", "-123.946846 | \n", "5576 | \n", "
4 | \n", "140.663762 | \n", "-21.868338 | \n", "80.400002 | \n", "-123.834244 | \n", "5576 | \n", "
... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
990982 | \n", "140.507566 | \n", "-21.870240 | \n", "79.269997 | \n", "-66.726227 | \n", "10166 | \n", "
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990986 | \n", "140.507569 | \n", "-21.870470 | \n", "80.070000 | \n", "-65.334846 | \n", "10166 | \n", "
990987 rows × 5 columns
\n", "\n", " | longitude | \n", "latitude | \n", "terrain_clearance_m | \n", "total_field_anomaly_nt | \n", "flight_line | \n", "
---|---|---|---|---|---|
0 | \n", "140.664111 | \n", "-21.868325 | \n", "80.699997 | \n", "-124.284653 | \n", "5576 | \n", "
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2 | \n", "140.663940 | \n", "-21.868325 | \n", "80.599998 | \n", "-124.069214 | \n", "5576 | \n", "
3 | \n", "140.663855 | \n", "-21.868325 | \n", "80.500000 | \n", "-123.946846 | \n", "5576 | \n", "
4 | \n", "140.663769 | \n", "-21.868324 | \n", "80.400002 | \n", "-123.834244 | \n", "5576 | \n", "
... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
990982 | \n", "140.507573 | \n", "-21.870226 | \n", "79.269997 | \n", "-66.726227 | \n", "10166 | \n", "
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990985 | \n", "140.507576 | \n", "-21.870398 | \n", "79.790001 | \n", "-65.685265 | \n", "10166 | \n", "
990986 | \n", "140.507577 | \n", "-21.870457 | \n", "80.070000 | \n", "-65.334846 | \n", "10166 | \n", "
990987 rows × 5 columns
\n", "\n", " | lat | \n", "lon | \n", "z | \n", "
---|---|---|---|
0 | \n", "-22.200000 | \n", "140.466667 | \n", "294.0 | \n", "
1 | \n", "-22.200000 | \n", "140.466944 | \n", "294.0 | \n", "
2 | \n", "-22.200000 | \n", "140.467222 | \n", "295.0 | \n", "
3 | \n", "-22.200000 | \n", "140.467500 | \n", "295.0 | \n", "
4 | \n", "-22.200000 | \n", "140.467778 | \n", "294.0 | \n", "
... | \n", "... | \n", "... | \n", "... | \n", "
2508776 | \n", "-21.716667 | \n", "140.865556 | \n", "346.0 | \n", "
2508777 | \n", "-21.716667 | \n", "140.865833 | \n", "350.0 | \n", "
2508778 | \n", "-21.716667 | \n", "140.866111 | \n", "356.0 | \n", "
2508779 | \n", "-21.716667 | \n", "140.866389 | \n", "359.0 | \n", "
2508780 | \n", "-21.716667 | \n", "140.866667 | \n", "360.0 | \n", "
2508781 rows × 3 columns
\n", "\n", " | longitude | \n", "latitude | \n", "terrain_clearance_m | \n", "total_field_anomaly_nt | \n", "flight_line | \n", "height_orthometric_m | \n", "
---|---|---|---|---|---|---|
0 | \n", "140.664111 | \n", "-21.868325 | \n", "80.699997 | \n", "-124.284653 | \n", "5576 | \n", "366.700012 | \n", "
1 | \n", "140.664025 | \n", "-21.868325 | \n", "80.599998 | \n", "-124.181824 | \n", "5576 | \n", "366.600006 | \n", "
2 | \n", "140.663940 | \n", "-21.868325 | \n", "80.599998 | \n", "-124.069214 | \n", "5576 | \n", "366.600006 | \n", "
3 | \n", "140.663855 | \n", "-21.868325 | \n", "80.500000 | \n", "-123.946846 | \n", "5576 | \n", "366.500000 | \n", "
4 | \n", "140.663769 | \n", "-21.868324 | \n", "80.400002 | \n", "-123.834244 | \n", "5576 | \n", "366.399994 | \n", "
... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
990982 | \n", "140.507573 | \n", "-21.870226 | \n", "79.269997 | \n", "-66.726227 | \n", "10166 | \n", "382.269989 | \n", "
990983 | \n", "140.507574 | \n", "-21.870285 | \n", "79.400002 | \n", "-66.385582 | \n", "10166 | \n", "382.399994 | \n", "
990984 | \n", "140.507575 | \n", "-21.870344 | \n", "79.580002 | \n", "-66.055672 | \n", "10166 | \n", "382.580017 | \n", "
990985 | \n", "140.507576 | \n", "-21.870398 | \n", "79.790001 | \n", "-65.685265 | \n", "10166 | \n", "382.790009 | \n", "
990986 | \n", "140.507577 | \n", "-21.870457 | \n", "80.070000 | \n", "-65.334846 | \n", "10166 | \n", "382.070007 | \n", "
990987 rows × 6 columns
\n", "\n", " | flight_line | \n", "longitude | \n", "latitude | \n", "height_orthometric_m | \n", "total_field_anomaly_nt | \n", "
---|---|---|---|---|---|
0 | \n", "5576 | \n", "140.66411 | \n", "-21.86833 | \n", "367 | \n", "-124 | \n", "
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2 | \n", "5576 | \n", "140.66394 | \n", "-21.86832 | \n", "367 | \n", "-124 | \n", "
3 | \n", "5576 | \n", "140.66385 | \n", "-21.86832 | \n", "366 | \n", "-124 | \n", "
4 | \n", "5576 | \n", "140.66377 | \n", "-21.86832 | \n", "366 | \n", "-124 | \n", "
... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
990982 | \n", "10166 | \n", "140.50757 | \n", "-21.87023 | \n", "382 | \n", "-67 | \n", "
990983 | \n", "10166 | \n", "140.50757 | \n", "-21.87029 | \n", "382 | \n", "-66 | \n", "
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990985 | \n", "10166 | \n", "140.50758 | \n", "-21.87040 | \n", "383 | \n", "-66 | \n", "
990986 | \n", "10166 | \n", "140.50758 | \n", "-21.87046 | \n", "382 | \n", "-65 | \n", "
990987 rows × 5 columns
\n", "\n", " | flight_line | \n", "longitude | \n", "latitude | \n", "height_orthometric_m | \n", "total_field_anomaly_nt | \n", "
---|---|---|---|---|---|
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... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
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990983 | \n", "10166 | \n", "140.50757 | \n", "-21.87029 | \n", "382 | \n", "-66 | \n", "
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990985 | \n", "10166 | \n", "140.50758 | \n", "-21.87040 | \n", "383 | \n", "-66 | \n", "
990986 | \n", "10166 | \n", "140.50758 | \n", "-21.87046 | \n", "382 | \n", "-65 | \n", "
990987 rows × 5 columns
\n", "