add ROI for Agulhas and Med Sea

Author: aashishpanta0

hands-on/session III/3.Tutorial_PetascaleAnalysis.ipynb

@@ -578,8 +578,18 @@
     "plt.colorbar(axp, location='right')\n",
     "\n",
     "# Define the corners of the subregion of interest\n",
-    "x1, x2 = 4500, 6000\n",
-    "y1, y2 = 800, 1400\n",
+    "\n",
+    "# For Agulhas Current, we can use the following coordinates\n",
+    "# These coordinates are approximate and can be adjusted based on the specific area of interest\n",
+    "# x1, x2 are longitude coordinates (in pixels)\n",
+    "# y1, y2 are latitude coordinates (in pixels)\n",
+    "x1, x2 = 800, 2400\n",
+    "y1, y2 = 2500, 3500\n",
+    "\n",
+    "# For Strait of Gibraltar, we can use the following coordinates:\n",
+    "x1, x2 = 400, 1600\n",
+    "y1, y2 = 4500, 5500\n",
+    "\n",
     "\n",
     "# Draw a red rectangle around the selected region\n",
     "regionRect = plt.Rectangle(\n",
@@ -686,7 +696,7 @@
     "\n",
     "- Load the `eastwest_ocean_velocity_u` dataset  \n",
     "- Select a specific **time step**, **resolution**, and **region** covering the Agulhas leakage area  \n",
-    "- Visualize the **east-west velocity component** of ocean currents  \n",
+    "- Visualize the **east-west velocity component** of ocean currents with proper colormap\n",
     "- Compute and report:\n",
     "  - The **maximum and minimum velocity values**\n",
     "  - The **structure of eddies** and current boundaries in the region\n",