diff --git a/docs/index.rst b/docs/index.rst
index 8e51831..779aa0a 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -13,44 +13,35 @@ Information about the GMT data server and mirrors can be found on the
 
    The highest resolution data for Mars, Mercury, Moon and Pluto requires GMT 6.5 or later.
 
+Geodesy
+~~~~~~~
+
 .. grid:: 1 2 3 3
     :gutter: 2
 
-    .. grid-item-card:: EarthByte Earth Seafloor Crustal Age
-        :link: earth-age
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_age_thumbnail.jpg
-        :text-align: center
-
     .. grid-item-card:: EGM2008 Earth Geoid
         :link: earth-geoid
         :link-type: doc
         :img-bottom: /_static/GMT_earth_geoid_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: EMAG2 Earth Magnetic Anomaly Model
-        :link: earth-mag
+    .. grid-item-card:: CNES Earth Mean Dynamic Topography
+        :link: earth-mdt
         :link-type: doc
-        :img-bottom: /_static/GMT_earth_mag_thumbnail.jpg
+        :img-bottom: /_static/GMT_earth_mdt_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: GEBCO Earth Relief
-        :link: earth-gebco
+    .. grid-item-card:: CNES Earth Mean Sea Surface
+        :link: earth-mss
         :link-type: doc
-        :img-bottom: /_static/GMT_earth_gebco_thumbnail.jpg
+        :img-bottom: /_static/GMT_earth_mss_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: GSHHG Earth Mask
-        :link: earth-mask
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_mask_thumbnail.jpg
-        :text-align: center
+Gravity
+~~~~~~~
 
-    .. grid-item-card:: GSHHG Earth Distance to Shoreline
-        :link: earth-dist
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_dist_thumbnail.jpg
-        :text-align: center
+.. grid:: 1 2 3 3
+    :gutter: 2
 
     .. grid-item-card:: IGPP Earth Free-Air Anomaly
         :link: earth-faa
@@ -70,46 +61,40 @@ Information about the GMT data server and mirrors can be found on the
         :img-bottom: /_static/GMT_earth_edefl_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: CNES Earth Mean Sea Surface
-        :link: earth-mss
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_mss_thumbnail.jpg
-        :text-align: center
-
-    .. grid-item-card:: CNES Earth Mean Dynamic Topography
-        :link: earth-mdt
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_mdt_thumbnail.jpg
-        :text-align: center
-
     .. grid-item-card:: IGPP Earth South-North Deflections
         :link: earth-ndefl
         :link-type: doc
         :img-bottom: /_static/GMT_earth_ndefl_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: IGPP Earth Relief
-        :link: earth-relief
-        :link-type: doc
-        :img-bottom: /_static/GMT_earth_relief_thumbnail.jpg
-        :text-align: center
-
     .. grid-item-card:: IGPP Earth Vertical Gravity Gradient
         :link: earth-vgg
         :link-type: doc
         :img-bottom: /_static/GMT_earth_vgg_thumbnail.jpg
         :text-align: center
 
+Images
+~~~~~~
+
+.. grid:: 1 2 3 3
+    :gutter: 2
+
     .. grid-item-card:: NASA Earth Day/Night Images
         :link: earth-daynight
         :link-type: doc
         :img-bottom: /_static/GMT_earth_daynight_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: NASA SRTM Relief
-        :link: srtm-relief
+Magnetics
+~~~~~~~~~
+
+.. grid:: 1 2 3 3
+    :gutter: 2
+
+    .. grid-item-card:: EMAG2 Earth Magnetic Anomaly Model
+        :link: earth-mag
         :link-type: doc
-        :img-bottom: /_static/GMT_srtm_relief_thumbnail.jpg
+        :img-bottom: /_static/GMT_earth_mag_thumbnail.jpg
         :text-align: center
 
     .. grid-item-card:: WDMAM World Digital Magnetic Anomaly Map
@@ -118,16 +103,40 @@ Information about the GMT data server and mirrors can be found on the
         :img-bottom: /_static/GMT_earth_wdmam_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: NASA Mars Relief
-        :link: mars-relief
+Miscellaneous
+~~~~~~~~~~~~~
+
+.. grid:: 1 2 3 3
+    :gutter: 2
+
+    .. grid-item-card:: EarthByte Earth Seafloor Crustal Age
+        :link: earth-age
         :link-type: doc
-        :img-bottom: /_static/GMT_mars_relief_thumbnail.jpg
+        :img-bottom: /_static/GMT_earth_age_thumbnail.jpg
         :text-align: center
 
-    .. grid-item-card:: USGS Mercury Relief
-        :link: mercury-relief
+    .. grid-item-card:: GSHHG Earth Distance to Shoreline
+        :link: earth-dist
         :link-type: doc
-        :img-bottom: /_static/GMT_mercury_relief_thumbnail.jpg
+        :img-bottom: /_static/GMT_earth_dist_thumbnail.jpg
+        :text-align: center
+
+    .. grid-item-card:: GSHHG Earth Mask
+        :link: earth-mask
+        :link-type: doc
+        :img-bottom: /_static/GMT_earth_mask_thumbnail.jpg
+        :text-align: center
+
+Other Celestial Bodies
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. grid:: 1 2 3 3
+    :gutter: 2
+
+    .. grid-item-card:: NASA Mars Relief
+        :link: mars-relief
+        :link-type: doc
+        :img-bottom: /_static/GMT_mars_relief_thumbnail.jpg
         :text-align: center
 
     .. grid-item-card:: USGS Moon Relief
@@ -136,6 +145,12 @@ Information about the GMT data server and mirrors can be found on the
         :img-bottom: /_static/GMT_moon_relief_thumbnail.jpg
         :text-align: center
 
+    .. grid-item-card:: USGS Mercury Relief
+        :link: mercury-relief
+        :link-type: doc
+        :img-bottom: /_static/GMT_mercury_relief_thumbnail.jpg
+        :text-align: center
+
     .. grid-item-card:: USGS Pluto Relief
         :link: pluto-relief
         :link-type: doc
@@ -148,34 +163,88 @@ Information about the GMT data server and mirrors can be found on the
         :img-bottom: /_static/GMT_venus_relief_thumbnail.jpg
         :text-align: center
 
+Topography
+~~~~~~~~~~
+
+.. grid:: 1 2 3 3
+    :gutter: 2
+
+    .. grid-item-card:: GEBCO Earth Relief
+        :link: earth-gebco
+        :link-type: doc
+        :img-bottom: /_static/GMT_earth_gebco_thumbnail.jpg
+        :text-align: center
+
+    .. grid-item-card:: IGPP Earth Relief
+        :link: earth-relief
+        :link-type: doc
+        :img-bottom: /_static/GMT_earth_relief_thumbnail.jpg
+        :text-align: center
+
+    .. grid-item-card:: NASA SRTM Relief
+        :link: srtm-relief
+        :link-type: doc
+        :img-bottom: /_static/GMT_srtm_relief_thumbnail.jpg
+        :text-align: center
+
 
 .. toctree::
    :hidden:
-   :caption: Datasets
+   :caption: Geodesy
 
-   earth-age
-   earth-daynight
-   earth-edefl
-   earth-dist
-   earth-faa
-   earth-faaerror
-   earth-gebco
    earth-geoid
-   earth-mag
-   earth-mask
    earth-mdt
    earth-mss
+
+.. toctree::
+   :hidden:
+   :caption: Gravity
+
+   earth-faa
+   earth-faaerror
+   earth-edefl
    earth-ndefl
-   earth-relief
    earth-vgg
-   srtm-relief
+
+.. toctree::
+   :hidden:
+   :caption: Images
+
+   earth-daynight
+
+.. toctree::
+   :hidden:
+   :caption: Magnetics
+
+   earth-mag
    earth-wdmam
+
+.. toctree::
+   :hidden:
+   :caption: Miscellaneous
+
+   earth-age
+   earth-dist
+   earth-mask
+
+.. toctree::
+   :hidden:
+   :caption: Other Celestial Bodies
+
    mars-relief
-   mercury-relief
    moon-relief
+   mercury-relief
    pluto-relief
    venus-relief
 
+.. toctree::
+   :hidden:
+   :caption: Topography
+
+   earth-gebco
+   earth-relief
+   srtm-relief
+
 .. toctree::
    :caption: Reference
    :hidden: