{ "cells": [ { "cell_type": "markdown", "id": "385d21fd-6f63-41d8-8633-79721f90fe8d", "metadata": {}, "source": [ "# Airborne magnetic survey of Britain\n", "\n", "This is a digitized version of an airborne magnetic survey of Britain. The exact date of measurements is not available (only the year). Flight height is estimated and not specified if it's geometric or orthometric. Given the error involved in how the data were digitized, it likely doesn't matter which. The horizontal datum is OSGB36 (epsg:27700) and we convert the data to WGS84 for standardization.\n", "\n", "Contains British Geological Survey materials © UKRI 2021\n", "\n", "License: [Open Government Licence](https://www.bgs.ac.uk/bgs-intellectual-property-rights/open-government-licence/)" ] }, { "cell_type": "code", "execution_count": 1, "id": "34fa5814-2463-44eb-97a1-9aa57670e3df", "metadata": {}, "outputs": [], "source": [ "import os\n", "import matplotlib.pyplot as plt\n", "import numpy as np\n", "import pandas as pd\n", "import verde as vd\n", "import pooch\n", "import pyproj\n", "import pygmt" ] }, { "cell_type": "markdown", "id": "15c63575-49cf-4503-86fe-abd6f455f552", "metadata": {}, "source": [ "## Download the data archive\n", "\n", "Use Pooch to download the data archive and fetch the CSV file only (not the PDF reports included)." ] }, { "cell_type": "code", "execution_count": 2, "id": "50ee303e-927d-4ba8-8d3e-e3c8849505ec", "metadata": {}, "outputs": [], "source": [ "fnames = pooch.retrieve(\n", " url=\"https://www.bgs.ac.uk/?wpdmdl=11839\",\n", " fname=\"britain-aeromag.zip\",\n", " known_hash=\"md5:e9968928e1c156bfe318bfb84657a472\",\n", " # Unpack and return only the actual data, not the reports.\n", " processor=pooch.Unzip(members=[\"Aeromag_csv/aeromag.csv\"]),\n", ")\n", "fname = fnames[0]" ] }, { "cell_type": "code", "execution_count": 3, "id": "fbc2e32b-9b7c-4404-925c-9e00a7c12ff6", "metadata": {}, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "size: 43.499991 Mb\n" ] } ], "source": [ "print(f\"size: {os.path.getsize(fname) / 1e6} Mb\")" ] }, { "cell_type": "markdown", "id": "86ca37f7-c83c-4741-941b-27c29f6d70f8", "metadata": {}, "source": [ "## Read the data\n", "\n", "Use pandas to load the CSV file." ] }, { "cell_type": "code", "execution_count": 4, "id": "6bbd81fa-0f94-46e0-b458-a324295b6e2b", "metadata": {}, "outputs": [ { "data": { "text/html": [ "
| \n", " | survey | \n", "line_and_segment | \n", "longitude_osgb | \n", "latitude_osgb | \n", "height_m | \n", "total_field_anomaly_nt | \n", "
|---|---|---|---|---|---|---|
| 0 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.74012 | \n", "53.48138 | \n", "792 | \n", "62 | \n", "
| 1 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.69972 | \n", "53.48326 | \n", "663 | \n", "56 | \n", "
| 2 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07893 | \n", "53.47650 | \n", "315 | \n", "30 | \n", "
| 3 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07313 | \n", "53.47645 | \n", "315 | \n", "31 | \n", "
| 4 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.01604 | \n", "53.47559 | \n", "321 | \n", "44 | \n", "
| ... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
| 541503 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68710 | \n", "58.26822 | \n", "1031 | \n", "64 | \n", "
| 541504 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68517 | \n", "58.26822 | \n", "1045 | \n", "74 | \n", "
| 541505 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68402 | \n", "58.26826 | \n", "1035 | \n", "94 | \n", "
| 541506 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68286 | \n", "58.26823 | \n", "1024 | \n", "114 | \n", "
| 541507 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68141 | \n", "58.26826 | \n", "1011 | \n", "120 | \n", "
541508 rows × 6 columns
\n", "| \n", " | survey | \n", "line_and_segment | \n", "longitude_osgb | \n", "latitude_osgb | \n", "height_m | \n", "total_field_anomaly_nt | \n", "year | \n", "
|---|---|---|---|---|---|---|---|
| 0 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.74012 | \n", "53.48138 | \n", "792 | \n", "62 | \n", "1955 | \n", "
| 1 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.69972 | \n", "53.48326 | \n", "663 | \n", "56 | \n", "1955 | \n", "
| 2 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07893 | \n", "53.47650 | \n", "315 | \n", "30 | \n", "1955 | \n", "
| 3 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07313 | \n", "53.47645 | \n", "315 | \n", "31 | \n", "1955 | \n", "
| 4 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.01604 | \n", "53.47559 | \n", "321 | \n", "44 | \n", "1955 | \n", "
| ... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
| 541503 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68710 | \n", "58.26822 | \n", "1031 | \n", "64 | \n", "1965 | \n", "
| 541504 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68517 | \n", "58.26822 | \n", "1045 | \n", "74 | \n", "1965 | \n", "
| 541505 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68402 | \n", "58.26826 | \n", "1035 | \n", "94 | \n", "1965 | \n", "
| 541506 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68286 | \n", "58.26823 | \n", "1024 | \n", "114 | \n", "1965 | \n", "
| 541507 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68141 | \n", "58.26826 | \n", "1011 | \n", "120 | \n", "1965 | \n", "
541508 rows × 7 columns
\n", "| \n", " | survey | \n", "line_and_segment | \n", "longitude_osgb | \n", "latitude_osgb | \n", "height_m | \n", "total_field_anomaly_nt | \n", "year | \n", "longitude | \n", "latitude | \n", "
|---|---|---|---|---|---|---|---|---|---|
| 0 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.74012 | \n", "53.48138 | \n", "792 | \n", "62 | \n", "1955 | \n", "-1.741619 | \n", "53.481635 | \n", "
| 1 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.69972 | \n", "53.48326 | \n", "663 | \n", "56 | \n", "1955 | \n", "-1.701224 | \n", "53.483516 | \n", "
| 2 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07893 | \n", "53.47650 | \n", "315 | \n", "30 | \n", "1955 | \n", "-1.080508 | \n", "53.476766 | \n", "
| 3 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.07313 | \n", "53.47645 | \n", "315 | \n", "31 | \n", "1955 | \n", "-1.074709 | \n", "53.476716 | \n", "
| 4 | \n", "CA55_NORTH | \n", "FL1-1 | \n", "-1.01604 | \n", "53.47559 | \n", "321 | \n", "44 | \n", "1955 | \n", "-1.017626 | \n", "53.475857 | \n", "
| ... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
| 541503 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68710 | \n", "58.26822 | \n", "1031 | \n", "64 | \n", "1965 | \n", "-4.688428 | \n", "58.267865 | \n", "
| 541504 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68517 | \n", "58.26822 | \n", "1045 | \n", "74 | \n", "1965 | \n", "-4.686498 | \n", "58.267865 | \n", "
| 541505 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68402 | \n", "58.26826 | \n", "1035 | \n", "94 | \n", "1965 | \n", "-4.685348 | \n", "58.267905 | \n", "
| 541506 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68286 | \n", "58.26823 | \n", "1024 | \n", "114 | \n", "1965 | \n", "-4.684188 | \n", "58.267875 | \n", "
| 541507 | \n", "HG65 | \n", "FL-3(TL10-24)-1 | \n", "-4.68141 | \n", "58.26826 | \n", "1011 | \n", "120 | \n", "1965 | \n", "-4.682738 | \n", "58.267905 | \n", "
541508 rows × 9 columns
\n", "| \n", " | line_and_segment | \n", "year | \n", "longitude | \n", "latitude | \n", "height_m | \n", "total_field_anomaly_nt | \n", "
|---|---|---|---|---|---|---|
| 0 | \n", "FL1-1 | \n", "1955 | \n", "-1.74162 | \n", "53.48164 | \n", "792 | \n", "62 | \n", "
| 1 | \n", "FL1-1 | \n", "1955 | \n", "-1.70122 | \n", "53.48352 | \n", "663 | \n", "56 | \n", "
| 2 | \n", "FL1-1 | \n", "1955 | \n", "-1.08051 | \n", "53.47677 | \n", "315 | \n", "30 | \n", "
| 3 | \n", "FL1-1 | \n", "1955 | \n", "-1.07471 | \n", "53.47672 | \n", "315 | \n", "31 | \n", "
| 4 | \n", "FL1-1 | \n", "1955 | \n", "-1.01763 | \n", "53.47586 | \n", "321 | \n", "44 | \n", "
| ... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
| 541503 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68843 | \n", "58.26786 | \n", "1031 | \n", "64 | \n", "
| 541504 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68650 | \n", "58.26786 | \n", "1045 | \n", "74 | \n", "
| 541505 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68535 | \n", "58.26790 | \n", "1035 | \n", "94 | \n", "
| 541506 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68419 | \n", "58.26787 | \n", "1024 | \n", "114 | \n", "
| 541507 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68274 | \n", "58.26790 | \n", "1011 | \n", "120 | \n", "
541508 rows × 6 columns
\n", "| \n", " | line_and_segment | \n", "year | \n", "longitude | \n", "latitude | \n", "height_m | \n", "total_field_anomaly_nt | \n", "
|---|---|---|---|---|---|---|
| 0 | \n", "FL1-1 | \n", "1955 | \n", "-1.74162 | \n", "53.48164 | \n", "792 | \n", "62 | \n", "
| 1 | \n", "FL1-1 | \n", "1955 | \n", "-1.70122 | \n", "53.48352 | \n", "663 | \n", "56 | \n", "
| 2 | \n", "FL1-1 | \n", "1955 | \n", "-1.08051 | \n", "53.47677 | \n", "315 | \n", "30 | \n", "
| 3 | \n", "FL1-1 | \n", "1955 | \n", "-1.07471 | \n", "53.47672 | \n", "315 | \n", "31 | \n", "
| 4 | \n", "FL1-1 | \n", "1955 | \n", "-1.01763 | \n", "53.47586 | \n", "321 | \n", "44 | \n", "
| ... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "... | \n", "
| 541503 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68843 | \n", "58.26786 | \n", "1031 | \n", "64 | \n", "
| 541504 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68650 | \n", "58.26786 | \n", "1045 | \n", "74 | \n", "
| 541505 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68535 | \n", "58.26790 | \n", "1035 | \n", "94 | \n", "
| 541506 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68419 | \n", "58.26787 | \n", "1024 | \n", "114 | \n", "
| 541507 | \n", "FL-3(TL10-24)-1 | \n", "1965 | \n", "-4.68274 | \n", "58.26790 | \n", "1011 | \n", "120 | \n", "
541508 rows × 6 columns
\n", "