{
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    {
      "cell_type": "code",
      "execution_count": null,
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      "source": [
        "%matplotlib inline"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n# Detrended Ordinary Kriging\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "import numpy as np\n\nfrom gstools import SRF, Gaussian, krige\n\n\ndef trend(x):\n    \"\"\"Example for a simple linear trend.\"\"\"\n    return x * 0.1 + 1\n\n\n# synthetic condtions with trend/drift\ndrift_model = Gaussian(dim=1, var=0.1, len_scale=2)\ndrift = SRF(drift_model, seed=101)\ncond_pos = np.linspace(0.1, 8, 10)\ncond_val = drift(cond_pos) + trend(cond_pos)\n# resulting grid\ngridx = np.linspace(0.0, 15.0, 151)\ndrift_field = drift(gridx) + trend(gridx)\n# kriging\nmodel = Gaussian(dim=1, var=0.1, len_scale=2)\nkrig_trend = krige.Ordinary(model, cond_pos, cond_val, trend=trend)\nkrig_trend(gridx)\nax = krig_trend.plot()\nax.scatter(cond_pos, cond_val, color=\"k\", zorder=10, label=\"Conditions\")\nax.plot(gridx, trend(gridx), \":\", label=\"linear trend\")\nax.plot(gridx, drift_field, \"--\", label=\"original field\")\nax.legend()"
      ]
    }
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