  The desktop GUI catalogue analysis tool TOPCAT, and its command-line
counterpart STILTS, offer among other capabilities visual exploration of
locally stored tables containing millions of rows or more. They offer many
variations on the theme of scatter plots, density maps and histograms, which
can be navigated interactively. These capabilities have now been extended to a
client-server model, so that a plot server can be run close to the data
storage, and remote lightweight HTML/JavaScript clients can configure and
interact with plots based on that data. The interaction can include
pan/zoom/rotate navigation, identifying individual points, and potentially
subset selection. Since only the pixels and not the row data are transmitted to
the client, this enables flexible remote visual exploration of large tables at
relatively low bandwidth. The web client can request any of the plot options
available from TOPCAT/STILTS. Possible applications include web-based
visualisations of static datasets too large to transmit, visual previews of
archive search results, service-configured arrays of plots for complex
datasets, and embedding visualisations of local or remote tables into Jupyter
notebooks.
