A sampling apparatus and method of obtaining a sample are provided. The sliding drawer has a storage chamber defined therein, and a mounting bracket is secured to the sliding drawer and extends into the storage chamber. Pixel data for such specified objects may be encoded using the appropriate object-specific threshold halftone lookup table into one of two multi-bit values, which serve to increase the frequency of repetitive or redundant encoded data and permit efficient compression by algorithms that exploit data repetition andor redundancy. The microporous cation exchangers are represented by the following empirical formula. Then the server generates a data for displaying an input assistance screen based on the image data and the positions of items and transmits the generated data to the client apparatus where the input assistance screen is displayed.