fix wording

Author: reint-fischer

docs/user_guide/examples/tutorial_unitconverters.ipynb

@@ -5,7 +5,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Spherical grids and unit conversion\n"
+    "# Spherical grids and unit converters\n"
    ]
   },
   {
@@ -67,7 +67,7 @@
     "When using a `FieldSet` method for a specific dataset, such as `from_copernicusmarine()`, the grid information is known and parsed by Parcels, so we do not have to add the `mesh` argument.\n",
     "```\n",
     "\n",
-    "Plotting the `U` field indeed shows a uniform 1m/s eastward flow.\n"
+    "Plotting the `U` field indeed shows a uniform 1 m/s eastward flow.\n"
    ]
   },
   {
@@ -113,9 +113,13 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "print(fieldset.UV[np.array([0]), np.array([0]), np.array([40]), np.array([-5])])\n",
+    "time = np.array([0])\n",
+    "z = np.array([0])\n",
+    "lat = np.array([40])\n",
+    "lon = np.array([-5])\n",
+    "print(fieldset.UV[time, z, lat, lon])\n",
     "print(\n",
-    "    fieldset.temperature[np.array([0]), np.array([0]), np.array([40]), np.array([-5])]\n",
+    "    fieldset.temperature[time, z, lat, lon]\n",
     ")"
    ]
   },
@@ -126,7 +130,7 @@
    "source": [
     "While the temperature field indeed is 20C, as we defined, these printed velocities are much smaller.\n",
     "\n",
-    "This is because Parcels converts under the hood from m/s to degrees/s. This conversion is done with a `UnitConverter` object, which is stored in the `.units` attribute of each Field. Below, we print these\n"
+    "This is because Parcels converts under the hood from m/s to degrees/s. This conversion is done with a `parcels.converters` object, which is stored in the `.units` attribute of each Field. Below, we print these\n"
    ]
   },
   {
@@ -144,7 +148,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "So the U field has a `GeographicPolar` UnitConverter object, the V field has a `Geographic` Unitconverter and the `temp` field has a `UnitConverter` object.\n",
+    "So the U field has a `GeographicPolar` UnitConverter object, the V field has a `Geographic` UnitConverter and the `temp` field has a `UnitConverter` object.\n",
     "\n",
     "Indeed, if we multiply the value of the V field with 1852 \\* 60 (the number of meters in 1 degree of latitude), we get the expected 1 m/s.\n"
    ]
@@ -155,7 +159,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "u, v = fieldset.UV[np.array([0]), np.array([0]), np.array([40]), np.array([-5])]\n",
+    "u, v = fieldset.UV[time, z, lat, lon]\n",
     "print(v * 1852 * 60)"
    ]
   },
@@ -175,10 +179,10 @@
    "source": [
     "print(\n",
     "    fieldset.UV.eval(\n",
-    "        np.array([0]),\n",
-    "        np.array([0]),\n",
-    "        np.array([40]),\n",
-    "        np.array([-5]),\n",
+    "        time,\n",
+    "        z,\n",
+    "        lat,\n",
+    "        lon,\n",
     "        applyConversion=False,\n",
     "    )\n",
     ")"
@@ -235,7 +239,7 @@
     "\n",
     "print(\n",
     "    \"Velocities:\",\n",
-    "    fieldset_flat.UV[np.array([0]), np.array([0]), np.array([40]), np.array([-5])],\n",
+    "    fieldset_flat.UV[time, z, lat, lon],\n",
     ")\n",
     "for fld in [fieldset_flat.U, fieldset_flat.V, fieldset_flat.temperature]:\n",
     "    print(f\"{fld.name}: {fld.units}\")"
@@ -301,7 +305,7 @@
     "fieldset.add_field(kh_meridional_field)\n",
     "\n",
     "for fld in [fieldset.Kh_zonal, fieldset.Kh_meridional]:\n",
-    "    val = fld[np.array([0]), np.array([0]), np.array([40]), np.array([-5])]\n",
+    "    val = fld[time, z, lat, lon]\n",
     "    print(f\"{fld.name}: {val} {fld.units}\")"
    ]
   },
@@ -323,7 +327,7 @@
    "source": [
     "deg_to_m = 1852 * 60\n",
     "print(\n",
-    "    fieldset.Kh_meridional[np.array([0]), np.array([0]), np.array([40]), np.array([-5])]\n",
+    "    fieldset.Kh_meridional[time, z, lat, lon]\n",
     "    * deg_to_m**2\n",
     ")"
    ]
@@ -374,7 +378,7 @@
     "        interp_method=parcels.interpolators.XLinear,\n",
     "    )\n",
     ")\n",
-    "print(fieldset.Ustokes[np.array([0]), np.array([0]), np.array([40]), np.array([-5])])"
+    "print(fieldset.Ustokes[time, z, lat, lon])"
    ]
   },
   {
@@ -392,9 +396,9 @@
    "outputs": [],
    "source": [
     "fieldset.Ustokes.units = parcels.GeographicPolar()\n",
-    "print(fieldset.Ustokes[np.array([0]), np.array([0]), np.array([40]), np.array([-5])])\n",
+    "print(fieldset.Ustokes[time, z, lat, lon])\n",
     "print(\n",
-    "    fieldset.Ustokes[np.array([0]), np.array([0]), np.array([40]), np.array([-5])]\n",
+    "    fieldset.Ustokes[time, z, lat, lon]\n",
     "    * 1852\n",
     "    * 60\n",
     "    * np.cos(40 * np.pi / 180)\n",