Old Maps Vs Google Earth

[Epyminia]

Hi, I am trying to superimpose a clip from Google Earth on an 18nth century map. Unfortunately the old mapmaker appears to have used a different scale for the vertical sense to the horizontal. I'm sure that this must be easy but how do I compress the map in the vertical sense without shrinking the horizontal? Any ideas ? E

[gwpriester]

There is a small (Lock Aspect Ratio) padlock icon on the Infobar at the top of the page. It should be in the unlocked position.

Also, right click on the padlock icon and make sure Smart Transform is not selected.

[handrawn]

whilst google earth uses a variant of the mercator map projection, it is one designed for the web - so it may still need some tweaking, as an 18th century [1700's] map, even if it is mercator, may well be different

larger the area the greater the divergence if so

something to be aware of ....

[Acorn]

So it is probably one of vertical scaling as @gwpriester put it - https://en.wikipedia.org/wiki/Histor...y_developments.

Which are you trying to change old or Google?

Acorn

[Epyminia]

Many thanks I hadn't realised that you could turn off both Aspect Ratio and Smart Transform. I, for some reason unknown, assumed that it was one or the other. Interesting to see that the 18nth century very attractive map uses a different scale for its horizontal and vertical distances!

[handrawn]

for most of us [I will acknowledge not all] the world is not flat it is round

therefore no flat map representation is 100% accurate

the old map uses a different scale for horizontal and vertical distances relative to what?

old maps are often representational - they are not necessarily based on actual surveys of the land, except very locally

large scale surveying was underway from the 1700's, so it depends what the map is and who made it [and for what]

[gwpriester]

The map may have been hand drawn vs based on surveys.

Smart Transform has never been a popular feature and it is so hidden that most are not aware that it is there.

[Epyminia]

Mea Culpa!
Sorry to have troubled you all but I did learn a new technique.
The old map is in fact quite accurate. The clipped Google Earth map was not flat but inclined. Thus distorting the perspective.
Sorry