[Therion] Question about "grid" command

[Benedikt Hallinger]

So, after reading the thbook (p. 31) again, I think I can answer that to 
myself.
But it would be good if someone could step in and confirm:

> <origin x> <origin y>
may be negative, depending in used CS.

> <x spacing> <y spacing> <x count> <y count>
Is not allowed to be negative:
- origin is always lower-left (southwest) corner, and spacing is assumed 
to be from west to east and south to north, thus always positive.
row and cols count cannot be zero or negative for obvious reasons.


Stay safe!
kind regards, Beni


Am 2021-02-24 8:18, schrieb Benedikt Hallinger:
> Good morning,
> while debugging
> https://github.com/hbeni/therionsurface2survex/issues/1 i stumbled
> upon a format question i did not give tought until yesterday.
> 
> With the "grid" command you specify coordinate origin and size of a
> surface grid:
>   grid <origin x> <origin y> <x spacing> <y spacing> <x count> <y 
> count>
> 
> 
> Until now i assumed that:
> 
> a) these data has to be all positive.
> But i'm not sure... origin may surely get negative (like in wgs89 and
> for example western and southern of the 0-meridian/equator)
> And also stepsize - might it get negative too (esp. with flipped grids 
> maybe)?
> 
> b) the spacing might only be integer numbers, not floats
> Is this true? I just got an example with not-round stepsize.
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