expand the blurbs

Author: kandersolar

docs/sphinx/source/reference/iotools.rst

@@ -20,9 +20,14 @@ of sources and file formats relevant to solar energy modeling.  See also
 Gridded resource data
 ---------------------
 
+Modeled irradiance and meteorological data, available for large regions of
+the world.
+
 Public datasets
 ^^^^^^^^^^^^^^^
 
+These APIs are free to access, although some require registration.
+
 PVGIS
 *****
 
@@ -74,6 +79,8 @@ Satellite-derived irradiance and weather data for the Americas.
 Commercial datasets
 ^^^^^^^^^^^^^^^^^^^
 
+Accessing these APIs typically requires payment.
+
 SolarAnywhere
 *************
 
@@ -108,6 +115,9 @@ Solargis
 Ground station data
 -------------------
 
+Measurements from various networks of irradiance and meteorological
+ground stations.
+
 BSRN
 ^^^^
 
@@ -171,6 +181,8 @@ A solar radiation network in the northwest USA, run by the University of Oregon.
 Weather data
 ------------
 
+Meteorological datasets from a variety of modeled and measured datasets.
+
 ACIS
 ^^^^
 
@@ -202,6 +214,8 @@ relatively lower quality.
 Generic data file readers
 -------------------------
 
+Functions for reading local irradiance/weather data files.
+
 .. autosummary::
    :toctree: generated/