Ruler graduations

I do a lot of campground maps and sometimes I need more accurate "Ruler" measurements. Could the graduations be less than 1/8". It would be helpful if the graduations were as little as 1/32"
Also, it would be helpful if the area where the two rulers intersect could have a pull down feature to the rulers where they could be centred on a specific place in the screen. ie: at the corner of an object on the screen. I have been using Corel Draw for 15 years and this feature was a key feature to use.