Image Servers in C++

The AstroCatalog class is also used to retrieve images from an image server 1 . The open method is used in the same way as for other catalogs:

 
AstroCatalog* cat = AstroCatalog::open(serverName); 
if (!cat)  
    error(...);

The return value from AstroCatalog::open is a pointer to an AstroCatalog object created for the given image server. To retrieve an image from the image server, you typically need to specify a position (or object name) and a width and height for the image (This is the default, however it depends on the config entry for the image server.):

 
WorldCoords pos(3, 19, 48, 41, 30, 39); 
AstroQuery q; 
q.pos(pos); 
q.width(2.0); 
q.height(3.5); 
if (cat->getImage(q) == 0) { 
    displayImage(cat->tmpfile()); 
}

Here the position is given as 3:19:48 +41:30:39, and the returned image should be 2.0 x 3.5 arcmins in size (centered at the position). The return value is the status (0 is OK, 1 for errors). The name of the temporary file containing the requested FITS image can be accessed by calling the method AstroCatalog::tmpfile() . The file should be copied if necessary, since it will be rewritten in the next call to getImage .

1. The AstroImage class, which was previously used for image servers, is now obsolete. Please use the AstroCatalog class for this now.