Update README

README.md

@@ -2,25 +2,27 @@
 
 mkgrid - Convert scattered data to regular gridded data in 2D, 3D, and 4D.
 
+
 # SYNOPSIS
 
 **mkgrid** [-\-*OPTION*]... *OUTFILE*
 
+
 # DESCRIPTION
 
 This script converts scattered data of dimensions in 2D, 3D, and 4D to regular gridded data.
 
-| Tag          | Method                             | 2D | 3D | 4D |
-| :----------- | ---------------------------------- | -- | -- | -- |
-| `linear`     | Linear interpolation               | T  | T  | T  |
-| `nearest`    | Nearest data point                 | T  | T  | T  |
-| `cubic`      | Cubic spline interpolation         | T  | T  | T  |
-| `nearest-up` | Nearest data point (rounded-up)    | T  | F  | F  |
-| `zero`       | Spline interpolation of 0th order  | T  | F  | F  |
-| `slinear`    | Spline interpolation of 1st order  | T  | F  | F  |
-| `quadratic`  | Spline interpolation of 2nd order  | T  | F  | F  |
-| `previous`   | Previous data point                | T  | F  | F  |
-| `next`       | Next data point                    | T  | F  | F  |
+The following interpolation methods are available:
+
+- Linear interpolation (default)
+- Nearest data point
+- Cubic spline interpolation
+- Nearest data point (rounded-up)
+- Spline interpolation of zeroth order
+- Spline interpolation of first order
+- Spline interpolation of second order
+- Previous data point
+- Next data point
 
 If output file `OUTFILE` is undefined, the output is directed to `STDOUT`.
 
@@ -33,7 +35,7 @@ If output file `OUTFILE` is undefined, the output is directed to `STDOUT`.
 
 - **-m**, **-\-method** *METHOD*
 
-  Set interpolation method.  If undefined, linear interpolation will be applied.
+  Set the interpolation method.  Select one of the following: `linear` (default), `nearest`, `cubic`.  The following options are available for 2D data only: `nearest-up`, `zero`, `slinear`, `quadratic`, `previous`, `next`.
 
 - **-p**, **-\-plot** [*FILENAME*]