GPS Notes

Notes

Some GPS locations are set by the eye on large-scale map.
Those might be inaccuracy!

Japanese maps which was publiched before 2000 is probably based on the [TOKYO]. The difference between [TOKYO] and current international base,[WGS84], is several hundred meters.

Destance between [TOKYO] and [WGS84]

Theses 2 positioning bases are different. So, when you use Japanese old maps, you should notice about these distances.

B[WGS84]=B[Tokyo]+dB : L[WGS84]=L[Tokyo]+dL

Difference of the Longtitude (dB) is 8 to13 Sec [250 to 400m].
Difference ot the Latitude(dL) is -8 to -15 Sec [-250 to -460m] .
(in case of on the land of Japan. It is depend on the position.)

You can get these parameters at following site.
GSI > Transformation Parameters

Or, you can convert the position
GSI > TKY2JGD [J]