To make a map, a baseline is determined and surveyed. The Sagamino baseline is the baseline connecting the first two reference points established for making a modern map.
I learned about its existence from a video called “Map Story.”
Sagami-Ono Station
The northern end of the Sagamino baseline is located in Asamizodai 4-chome, Minami-ku, Sagamihara City. It is a long way from any station, and I had trouble accessing it.
Sagami-Ono Station, Odakyu Odawara Line
In the end, I decided to walk there from Sagami-Ono station, where the train fare was the cheapest.
The path orthogonal to magnetic north
In advance, I used the Kashmir 3D software to create a map equivalent to 1:25,000, and walked while looking at it.
It was a hot and humid day. The roads were intricate, and I got lost in the narrow alleys.
Roads perpendicular to magnetic north
Finally, I came to a slightly wide street with sidewalks that ran along the south side of Sagami Women’s University. The street was a clean, straight line heading west.
Looking at the map at hand…
The road was slightly tilted from the horizontal east-west direction, but there was some kind of orthogonal line. And that line is the magnetic north line, isn’t it?
Oops.
The magnetic north line is the direction of north indicated by the compass and is inclined about 7 degrees west from true north. Kashmir 3D is a multifunctional software that can print the magnetic north line. Since I like to walk while using a compass, I always print out the magnetic north line.
The road that goes directly to the magnetic north line was probably built to improve surveying techniques. The area around the Sagamino baseline seems to be a city for mapping.
The site of Sagami Women’s University is rectangular in shape. The direction of the road passing through the east side intersecting with this road was nicely aligned with the magnetic north line.
High voltage power lines pointing to magnetic north
After walking about 1.5 km to the west, I saw the power lines.
The 1:25,000 map also shows power lines. I looked in that direction and smiled.
High voltage power lines pointing to magnetic north
When I came under the power lines, I took the first photo shown.
The compass needle and the direction of the power lines match, don’t they? In other words, the power lines are pointing to magnetic north.
It’s out of focus, though.
By the way, the number of insulators is about 21, which means that the power line is about 275kV.
North end of Sagamino baseline
The northern end of the Sagamino base line was hard to find, as it was surrounded by a wall.
But I guess it used to be a good vantage point.
North end of Sagamino baseline
Even though it is a very important triangle point, it does not assert itself, yet it has dignity. It’s just like a triangulation point representing Japan, which is really nice. It makes me feel so lucky to have been born Japanese.
The three pillars around the point are probably for tripods.
I took a moment to check the north latitude and east longitude with my GPS. It was 35 degrees 31 minutes 52.7 seconds north latitude and 139 degrees 24 minutes 23.2 seconds east longitude. According to Wikipedia, it was 35 degrees 31 minutes 52.54 seconds north latitude and 139 degrees 24 minutes 23.03 seconds east longitude.
There’s a bit of a difference, so I’ll try to calculate how many meters it equals next time.
Roads pointing to magnetic north
To the west of the northern end of the baseline, there is a road that runs north-south. This road also shows magnetic north.
In the photo, the compass appears to be slightly tilted to the left. If I had been standing 5 cm to the right when I took the photo, it would have looked perfectly straight. I’m sure.
Yes, there were a lot of poultry farms around here for some reason.
Sagamino base line midpoint
Sagamino base line midpoint
I also checked the midpoint of the baseline.
According to my own measurement, it was 35 degrees 30 minutes 38.7 seconds north latitude and 139 degrees 25 minutes 13.1 seconds east longitude, and according to Wikipedia, it was 35 degrees 30 minutes 38.76 seconds north latitude and 139 degrees 25 minutes 13.15 seconds east longitude, which was almost exactly right.
Zama City Manhole
Nearby, there was a manhole that is familiar to walkers. It looks like a sunflower, the flower of Zama City.
Shonan Cookie Vending Machine
Do they have Shonan Cookies in Zama City?
Whenever I come to Kanagawa Prefecture, I’m always very curious about the sales machines. This time I gave up because it was on the other side of the main street. I’m sure I’ll eat them someday.
South end of Sagamino baseline
South end of Sagamino baseline
This is the southern end of the Sagamino baseline.
When surveying, it seems difficult to even set up a tripod because of the close proximity of buildings.
The value measured on the road in front of us was 35 degrees 29 minutes 24.8 seconds north latitude and 139 degrees 26 minutes 03.2 seconds east longitude. Wikipedia gave us 35 degrees 29 minutes 24.7 seconds north latitude and 139 degrees 26 minutes 3.35 seconds east longitude, which was almost exactly the same.
Minamirinkan Station
I looked at my watch and saw that it was past 1:00 pm.
I decided to go back from Minamirinkan Station.
Menya Kotetsu’s Ramen with soy sauce
But I was hungry, so before I got on the train, I went to “Menya Kotetsu” near Minamirinkan Station and had some “Namara Shoyu Ramen”. The color was so dark that I was afraid it would splash on my clothes, but the taste was good.
Walking data
Course: Sagamiono Station on the Odakyu Odawara Line -> North end of Sagamino Base Line -> Midpoint -> South end -> Minamirinkan Station on the Odakyu Enoshima Line
Distance: approx. 12.3km
Time: 3h44m
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