# Daily Challenge Day 15

So yesterday I took another look at my ideas for occupation of land. In my previous article, I considered cells 5 km in diameter could be surveyed by a single person, and there are approximately 7 million such cells possible across the earth’s land area, therefore each nation has potential to place one person in each cell. The earth with a human population of approximately 7 billion can place 1000 persons in each cell.

Looking back at the Yorke Peninsula council area there are 297 possible cells. On considering walkability, and assuming 5 km/h average speed and 5 hours walking each day, then require towns or camping grounds at 25km centres, and I thus produced a map connecting towns in the council area if they were less than 25 km apart.

Last night however I was contemplating what would happen if put the 25 km node to node, triangulated network through large farming properties. Not sure how large farming properties are I just assumed a block 50km by 100km. Thus it would take 2 days to cross the width, and 4 days to walk the length, whilst a car at 100km/h on country roads would only take 1 hour to travel the length and half an hour to travel the width.

Not knowing anything about combined harvesters I assumed that its operating speed would be less than 25 km/h, and therefore it would take 2 hours to cross the width of the block and 4 hours to travel the length of the block. Then assume that a combined harvester or other agricultural machine as a maximum width of 10m. This was based on a vague memory of guinness book of records article around the late eighties mentioning a beam  around 9m to 12m long, running on concrete tracks. It was running on tracks to avoid sinking into the ground. So 10m was an easy number to work with. At 10m width there are 100 strips in 1 km.

Ignoring turning, then the total strip length is the same irrespective as whether strips cross the width or the length of the block: 500,000 km, which would take 20,000 hours to work, which at 2000 hr/year would take 10 years. So not really practical for one person to work, as the block of land needs to be worked in a single season, or quarter of 1 years hours, that is 500 hours. This drops the total strip length to 12,500 km.  So if the strip is 100km long, then the block would have a width of 1.25 km: not very wide. If strips are 25 km long, then the width increases to 5km wide.

Though the block could be reduced even further in size, if take into consideration the amount of work which could be done in a day. For simplicity assume a 10 hour work day, and therefore strip length is 250 km. So at 25km long, the width of the block would be 100m. At 5 km long strips the block width would be 500 m.

None of seems to be all that large, or much of a problem for a 25 km triangulated network, or even a 25 km square grid, nor for that matter a 5 km square grid.

So today did some research. Broadacre apparently is farms larger than 4000 sq.m, which would require a square block with sides approximately 64m. Another report indicated Australia’s farms have changed from a size of 2800 hectares, to a size of 4100 hectares. Given that 1 hectare = 100m x 100m = 10,000 sq.m the sizes are starting to seem a lot larger. But then again the largest only represents a square with side approximately 6.4 km. A 5km square walking grid still looking viable.

Some other research indicates that the 10m cut width and 25 km/h are potentially too high. Here is an article reviewing a combined harvester and giving values for it cuts width and operating speed. Most brochures I could find, didn’t explicitly give operating speed and cut width, though maximum travel speed of 40km/h quoted for. The Travel speed however, is not the operating speed for efficient harvesting of the crop. One article I found seemed to indicate that the optimum speed is 7.9km/h, at least based on the parameters they considered. A brochure for John Deere put the width at 4.30m to 9.15m. The history of combined harvesters would tend to put the typical width less than 5m.

So have speed less than 32% of what I used and width less than half what I considered. So whilst I may travel a 100km or more along roads adjacent to crop fields, it is unlikely those fields are very wide and worked by one person in a season.

So on the face of it, setting up a 5 km square grid of foot paths, and right of way for people to walk from anywhere to anywhere shouldn’t be obstructed by much of anything. And a 25 km square grid even less likely to conflict with anything.

Today I also installed wikicamps on my mobile, from that it seems there are plenty of campsites on the coastline of the Yorke Peninsula, but not too many inland. I suppose walking along the coastline isn’t too bad, but its not really an exploration of the region. Though I wouldn’t really want to be hiking along a road when a grain truck flys by.

The map I showed previously, connected towns if they were less than 25 km apart, what is really needed is to solve the travelling salesman problem to connect towns and campsites. With Concorde apparently being one way to do that, so something to look at in future. Though something which plugs into QGIS maybe more convenient.