Re: Grid map
The documentation for the XML request says:
The first Band defined in the XML is plotted last and therefore masks anything plotted underneath it.
I found out the hard way, and after much puzzling, that this is an important point to note! It means that, if you want two or three date classes, you need to define them in order with the most recent first: e.g 1985 - 2008; 1970 - 1984; 1600-1969, so that the most recent records "overlay" older records for the same square. Before reading this carefully, I had them the other way round (which seemed more intuitive to me!) and wondered why I had so many old records and so few recent ones on my maps! RTFM as they say.
The documentation also says:
If you complete only one or other of the years it will define all data before that date (if 'to' is set) or all data after that date (if a 'from' is set).
This does not seem to be correct, or at least I cannot get it to work like this. If I leave out either of the "from" or "to" parameters from a band, that band doesn't plot at all. The only way I could get it to work was to use the current year as the "to" parameter in the most recent band and some arbitrarily early date (e.g. 1600) in the "from" parameter of the oldest band. The oldest records held by the Hoverfly Recording Scheme are dated 1842, so this should cover it OK.