How are the 0.333, 0.555 and 0.777 bhoomi ratios derived?
In the 81 pad grid the line from the centre to a corner is 4.5 boxes long. From the centre, Brahma bhoomi ends at 1.5 boxes, Dev bhoomi at 2.5 and Manushya bhoomi at 3.5, and Pishach bhoomi runs to 4.5. Dividing by 4.5 gives 0.333, 0.555 and 0.777, which are applied to the real length of each centre-to-corner line on the map.
Related questions
When the house stands at the back of the plot with a garden in front, which centre is used to map the devtas?
Take the centre of the whole plot and map the devtas on it; all the open land around the house, even outside the building, becomes space for the devtas. This is why big houses abroad, as in America, are so balanced: about 4,000 sq ft is built on about 40,000 sq ft of land, so the 32 outer devtas get a huge, open pishach bhoomi and the manushya and dev bhoomi get cross ventilation from all sides. Just as a person given two acres of land enjoys the space, the devtas are pleased by big open land.
Why is there no line between manushya bhoomi and dev bhoomi on the 81-pada devta map?
In today's 81-pada vastu the manushya and dev bhoomi are combined, so only three divisions remain: the pishach bhoomi with the 32 outer devtas, the combined manushya-dev bhoomi with 12 devtas, and the brahma bhoomi with Brahma. After dividing the plan with the 0.33, 0.55 and 0.77 multipliers, erase the middle line between manushya and dev bhoomi, since it is not needed for placing the devtas.
A regular plot has small strips of land left open at the side and the front. Do we leave them out or zone the complete plot?
Zone the complete plot. Almost the whole plot is in use and even the small strips are being used, so the full plot is taken for zoning and for the degree.
Are the 32 outer devtas drawn in the Manushya bhoomi or in the Pishach bhoomi?
In the Pishach bhoomi, the outermost band. The 32 outer devta lines are drawn only within the Pishach bhoomi, while the 12 inner devtas sit in the combined Manushya and Dev band and Brahma in the centre.
At what degree do the corner directions (vidisha) fall?
North-East, South-East, South-West and North-West fall exactly 45 degrees from the main directions. Where they fall in your own flat becomes clear once you do the zoning.
Can the Google Earth method be done on a phone?
Google Earth with the ruler works only on a laptop or PC. On a phone you can use a photo editing app instead: take the chakra image in PNG form, ask the client for a photo of the map and overlay the chakra on it, which needs some photo editing skill.