Re: [Therion] Cave Overlays on Google Maps Web Sites

[Stacho Mudrak]

Quoting Bill Chadwick <address@hidden>:
> As this is quite a nice way of presenting cave surveys, perhaps a Google
> tile generator would be a good add on for Therion. The advantage of building
> the renderer into Therion would be that the overlay could be drawn
> separately for each Google Zoom level to achieve a good line width and text
> size.

Hmmm. Just one problem. Therion it self does not have any build-in  
bitmap generator. All maps are generated as vector PDF. And generation  
of bitmaps from PDF is very tricky (currently only Acrobat reader is  
able to render these PDF files 100% correct).

> I am well informed in the areas of coordinate systems and map projections
> and able to program in C++. With some guidance I might be able to help with
> the coding of such an extension.

I have tried to generate Google Earth's KML files from therion and it  
seems to work (scrap outlines for maps, centerline for model, try  
latest developement snapshot). All you need is to have georeferenced  
cave data (see "Coordinate Systems" in thbook). Then just

export model -fmt kml

will generate .kml file readable by Google Earth.

If somebody will create a good rasterizer script for PDF files  
generated by therion (using ghostscript or acroread), there is no  
problem for us to add export of long-lat coordinates together with PDF  
file to be used by this script.

S.

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