Complete documentation of grdimage

pygmt/base_plotting.py

@@ -318,24 +318,59 @@ def grdcontour(self, grid, **kwargs):
 
     @fmt_docstring
     @use_alias(
-        R="region",
-        J="projection",
-        W="pen",
+        A="img_out",
         B="frame",
-        I="shading",
         C="cmap",
+        D="img_in",
+        E="dpi",
+        G="bit_color",
+        I="shading",
+        J="projection",
+        M="monochrome",
+        N="no_clip",
+        Q="nan_transparent",
+        R="region",
+        U="timestamp",
+        V="verbose",
         X="xshift",
         Y="yshift",
+        n="interpolation",
         p="perspective",
         t="transparency",
         x="cores",
     )
     @kwargs_to_strings(R="sequence", p="sequence")
     def grdimage(self, grid, **kwargs):
         """
-        Project grids or images and plot them on maps.
-
-        Takes a grid file name or an xarray.DataArray object as input.
+        Project and plot grids or images.
+
+        Reads a 2-D grid file and produces a gray-shaded (or colored) map by
+        building a rectangular image and assigning pixels a gray-shade (or
+        color) based on the z-value and the CPT file. Optionally, illumination
+        may be added by providing a file with intensities in the (-1,+1) range
+        or instructions to derive intensities from the input data grid. Values
+        outside this range will be clipped. Such intensity files can be created
+        from the grid using `grdgradient` and, optionally, modified by
+        `grdmath` or `grdhisteq`. If GMT is built with GDAL support, *grid* can
+        be an image file (geo-referenced or not). In this case the image can
+        optionally be illuminated with the file provided via the *shading*
+        option. Here, if image has no coordinates then those of the intensity
+        file will be used.
+
+        When using map projections, the grid is first resampled on a new
+        rectangular grid with the same dimensions. Higher resolution images can
+        be obtained by using the *dpi* option. To obtain the resampled value
+        (and hence shade or color) of each map pixel, its location is inversely
+        projected back onto the input grid after which a value is interpolated
+        between the surrounding input grid values. By default bi-cubic
+        interpolation is used. Aliasing is avoided by also forward projecting
+        the input grid nodes. If two or more nodes are projected onto the same
+        pixel, their average will dominate in the calculation of the pixel
+        value. Interpolation and aliasing is controlled with the
+        *interpolation* option.
+
+        The *region* option can be used to select a map region larger or
+        smaller than that implied by the extent of the grid.
 
         Full option list at :gmt-docs:`grdimage.html`
 
@@ -344,8 +379,82 @@ def grdimage(self, grid, **kwargs):
         Parameters
         ----------
         grid : str or xarray.DataArray
-            The file name of the input grid or the grid loaded as a DataArray.
+            The file name or a DataArray containing the input 2-D gridded data
+            set or image to be plotted (See GRID FILE FORMATS at
+            :gmt-docs:`grdimage.html#grid-file-formats`).
+        img_out : str
+            ``out_img[=driver]``.
+            Save an image in a raster format instead of PostScript. Use
+            extension .ppm for a Portable Pixel Map format which is the only
+            raster format GMT can natively write. For GMT installations
+            configured with GDAL support there are more choices: Append
+            *out_img* to select the image file name and extension. If the
+            extension is one of .bmp, .gif, .jpg, .png, or .tif then no driver
+            information is required. For other output formats you must append
+            the required GDAL driver. The *driver* is the driver code name used
+            by GDAL; see your GDAL installation's documentation for available
+            drivers. Append a **+c**\\ *options* string where options is a list
+            of one or more concatenated number of GDAL **-co** options. For
+            example, to write a GeoPDF with the TerraGo format use
+            ``=PDF+cGEO_ENCODING=OGC_BP``. Notes: (1) If a tiff file (.tif) is
+            selected then we will write a GeoTiff image if the GMT projection
+            syntax translates into a PROJ syntax, otherwise a plain tiff file
+            is produced. (2) Any vector elements will be lost.
+        {B}
+        {CPT}
+        img_in : str
+            ``[r]``
+            GMT will automatically detect standard image files (Geotiff, TIFF,
+            JPG, PNG, GIF, etc.) and will read those via GDAL. For very obscure
+            image formats you may need to explicitly set *img_in*, which
+            specifies that the grid is in fact an image file to be read via
+            GDAL. Append **r** to assign the region specified by *region*
+            to the image. For example, if you have used ``region='d'`` then the
+            image will be assigned a global domain. This mode allows you to
+            project a raw image (an image without referencing coordinates).
+        dpi : int
+            ``[i|dpi]``.
+            Sets the resolution of the projected grid that will be created if a
+            map projection other than Linear or Mercator was selected [100]. By
+            default, the projected grid will be of the same size (rows and
+            columns) as the input file. Specify **i** to use the PostScript
+            image operator to interpolate the image at the device resolution.
+        bit_color : str
+            ``color[+b|f]``.
+            This option only applies when a resulting 1-bit image otherwise
+            would consist of only two colors: black (0) and white (255). If so,
+            this option will instead use the image as a transparent mask and
+            paint the mask with the given color. Append **+b** to paint the
+            background pixels (1) or **+f** for the foreground pixels
+            [Default].
+        shading : str
+            ``[intensfile|intensity|modifiers]``.
+            Give the name of a grid file with intensities in the (-1,+1) range,
+            or a constant intensity to apply everywhere (affects the ambient
+            light). Alternatively, derive an intensity grid from the input data
+            grid via a call to `grdgradient`; append **+a**\\ *azimuth*,
+            **+n**\\ *args*, and **+m**\\ *ambient* to specify azimuth,
+            intensity, and ambient arguments for that module, or just give
+            **+d** to select the default arguments (``+a-45+nt1+m0``). If you
+            want a more specific intensity scenario then run `grdgradient`
+            separately first. If we should derive intensities from another file
+            than grid, specify the file with suitable modifiers [Default is no
+            illumination].
+        {J}
+        monochrome : bool
+            Force conversion to monochrome image using the (television) YIQ
+            transformation. Cannot be used with *nan_transparent*.
+        no_clip : bool
+            Do not clip the image at the map boundary (only relevant for
+            non-rectangular maps).
+        nan_transparent : bool
+            Make grid nodes with z = NaN transparent, using the color-masking
+            feature in PostScript Level 3 (the PS device must support PS Level
+            3).
+        {R}
+        {V}
         {XY}
+        {n}
         {p}
         {t}
         {x}