So this would be a very inefficient way to do absolute positioning of the camera (but then, that is what 'PositionABS' is for). That said, the underlying math seems to indicate a logarithmic function is driving this motion:
degrees = -18.99666 + 6.9773*ln(position)
Although the low end of this...
Indeed it does look like they have removed it. At least from the cgi interface. The JS libraries seems to support it, but I have not documentation on those.
The doc @tangent mentions has a 'Position' code which appears to produce relative movement. The units are not clear, but doing a little...
According to the Dahua API spec 1.67, the following should cause the camera to pan relatively 100*
http://xxx.xxx.xxx.xxx/cgi-bin/ptz.cgi?action=start&code=Relatively&channel=0&arg1=100&arg2=0&arg3=0&Arg4=0
However, it results in:
Error
Bad Request!
A little digging shows a JS method named...