The Mercator projection is a legacy of people needing a world map in which local regions preserve accurate directions and proportional distances (i.e., people who need a map for navigation instead of a global dick-measuring contest).
No one uses a world map for navigation. Even when paper maps were still used, you would use it on a much smaller scale like a grid system. Even maritime maps would at largest only need to show an ocean.
It’s much easier to accurately represent directions and proportional distances when you’re not trying to fit the surface of a whole sphere onto one quadrilateral plane.
What? The projection matters on any scale and for navigational purposes will continue to use mercator projection on flat maps so there this decision doesn’t change anything.
It really doesn’t. On a ball as large as the earth, if you take a tiny section of it, it’s basically already flat. You don’t need to transform it mathematically to make it fit on a grid system.
Maybe you’ve never seen a map made for land navigation? They don’t need to distort terrain feature size to make everything line up directionally.
Maybe you’ve never seen a map made for land navigation?
Can you share one or the name of the projection used? I am having an harf time searching for it
Edit: i found that for air navigation they use Lambert Conformal Conic, for marine they use Mercator and for land i found nothing which makes sense (and probably it would be Mercator anyway)
A local coordinate system uses a false origin (0, 0 or other values) in an arbitrary location anywhere on earth. Local coordinate systems are often used for large-scale (small area) mapping. The false origin may or may not be aligned to a known real-world coordinate, but for the purpose of data capture, bearings and distances can be measured using the local coordinate system rather than global coordinates. Local coordinate systems are usually expressed in meters or feet.
I want to contradict you slightly: people don’t use world maps for navigation, but most are still using a world map projection, just zoomed in. Most map services like Google maps, mapquest, etc use something called the Web Mercator at all levels of zoom, i think because of the challenge of needing to zoom in anywhere on the map. I am not an expert on why they use the web mercator though.
I didn’t say they don’t use projections, I just said they don’t use world maps. Localized maps are much easier to achieve accuracy of both distance and direction
In the times of GPS, global navigation isn’t reliant on this specific map projection. On a local level (City or State/Province level), where most navigation for non-experts is taking place, the chosen map projection doesn’t matter that much. The people who are navigating distances where these things become relevant (pilots and ship navigators) are also expert enough to deal with most map projections. But for global issues, a map projection that actually represents land masses as they are in reality matters a lot.
Edit: I am aware about issues regarding GPS jamming. The latest tests regarding quantum navigation (which uses differences in earths gravity fiels) were working very well, so if jamming becomes a very common issue, these systems will proliferate quickly.
On a local level (City or State/Province level), where most navigation for non-experts is taking place, the chosen map projection doesn’t matter that much.
Yes, it does, because on a local level you want real-world right angles to be right angles on the map, which Mercator does, but other projections might not…
Most navigation software doesn’t show the map from the top, but from behind looking forward, and it communicates turns and lanes to choose regardless if your angles are 90° / 95° / 85° or what map projection is used. If you are still using paper maps in your own city - welcome to the future.
Edit: And to top it off, the crossroads being 90° is a uniquely american thing - every city in europe has a naturally grown layout. Since the US doesn’t give a fuck about anyone else (as seen in the vote and their renaming stuff into <whatever> America) I also don’t give a fuck about what maps they use.
Edit 2: If you use your current position as the center of the projection, anything close enough to be relevant stays at 90° - or so close that i dare anyone to see the difference.
I was making maps as an intern for the city government, and my biggest problem was that the Mercator made the city look much wider than it really was.
I’m not sure about the 90 degree angle thing, but i wanted to point out that navigation is only one reason someone might use a map, and then agree with you that using a projection centered near the local area is probably going to be best 9/10 times.
I seem to have upset some mercator afficionados. As you say, for everyday usage any type centered on you (or a bit in front of your position) will be close enough to reality that navigating will be fine. For city planning the true size of things also matter a lot, as you mentioned. Long distance navigation doesn’t use paper maps anymore except when GPS is jammed (which is not the norm if you aren’t near Iran or Ukraine currently), and we are already on the way to make quantum navigation for ships feasable. In the case of aircraft, if GPS is down, there are more than enough alternative ways to navigate (communication with flight control, ground based beacons and so on) and long distance road travel will in 99% of cases use high tier roads which tend to have signs indicating where they go, in addition to navigation software that could adjust map projection on the fly if needed (but it isn’t really needed, what you need is accurate lane and turn information, which is independent of what you see on the display).
I really don’t understand the hive mind in this case. Anyone having some input here where the issue lies? I haven’t touched a paper map where any of this stuff had mattered at least since the turn of the century.
Do you really think that the distortion over the short distance shown while navigating matters? I don’t know many drivers that actually use their geometry kit when using a navigation app.
People use digital maps for all kinds of purposes, not just navigating while driving.
For example I often look at digital maps as a pedestrian in order to know which direction to walk (even without actually entering navigation mode), or in order to find out where places of interest are around me, and there it definitely helps that the angles are the same in reality as on the map.
I didn’t know you live so close to the arctic that you can’t identify the direction you need to go when looking at a paper map.
With navigation software that simply uses your current position for the center of the projection all corners stay so close to reality that i dare you to see the difference (we are not living on a globe the size of a tangerine). There’s also the hint you get from the small arrow pointing out the direction you are currently facing.
I’m fairly sure the software care a great deal about projections and which chart datum is used. Just because it’s abstracted and invisible for the user I’m fairly sure you would notice if google maps stopped accepting wgs-84 positions or if they changed into an inverted projection. So yes it matters a great deal even on local levels.
The Mercator projection is a legacy of people needing a world map in which local regions preserve accurate directions and proportional distances (i.e., people who need a map for navigation instead of a global dick-measuring contest).
No one uses a world map for navigation. Even when paper maps were still used, you would use it on a much smaller scale like a grid system. Even maritime maps would at largest only need to show an ocean.
It’s much easier to accurately represent directions and proportional distances when you’re not trying to fit the surface of a whole sphere onto one quadrilateral plane.
What? The projection matters on any scale and for navigational purposes will continue to use mercator projection on flat maps so there this decision doesn’t change anything.
It really doesn’t. On a ball as large as the earth, if you take a tiny section of it, it’s basically already flat. You don’t need to transform it mathematically to make it fit on a grid system.
Maybe you’ve never seen a map made for land navigation? They don’t need to distort terrain feature size to make everything line up directionally.
Can you share one or the name of the projection used? I am having an harf time searching for it
Edit: i found that for air navigation they use Lambert Conformal Conic, for marine they use Mercator and for land i found nothing which makes sense (and probably it would be Mercator anyway)
https://doc.esri.com/en/arcgis-pro/latest/help/mapping/properties/coordinate-systems-and-projections.html
Example:
https://slcprdpublicrecords.blob.core.windows.net/0001sjradmin/PDF/CB_1877_15_10045793.pdf
Nice, thanks
I want to contradict you slightly: people don’t use world maps for navigation, but most are still using a world map projection, just zoomed in. Most map services like Google maps, mapquest, etc use something called the Web Mercator at all levels of zoom, i think because of the challenge of needing to zoom in anywhere on the map. I am not an expert on why they use the web mercator though.
I didn’t say they don’t use projections, I just said they don’t use world maps. Localized maps are much easier to achieve accuracy of both distance and direction
Hence the clarification! They do use world map projections. I don’t think they have to, but do for efficiency? Not an expert.
In the times of GPS, global navigation isn’t reliant on this specific map projection. On a local level (City or State/Province level), where most navigation for non-experts is taking place, the chosen map projection doesn’t matter that much. The people who are navigating distances where these things become relevant (pilots and ship navigators) are also expert enough to deal with most map projections. But for global issues, a map projection that actually represents land masses as they are in reality matters a lot.
Edit: I am aware about issues regarding GPS jamming. The latest tests regarding quantum navigation (which uses differences in earths gravity fiels) were working very well, so if jamming becomes a very common issue, these systems will proliferate quickly.
Yes, it does, because on a local level you want real-world right angles to be right angles on the map, which Mercator does, but other projections might not…
Most navigation software doesn’t show the map from the top, but from behind looking forward, and it communicates turns and lanes to choose regardless if your angles are 90° / 95° / 85° or what map projection is used. If you are still using paper maps in your own city - welcome to the future.
Edit: And to top it off, the crossroads being 90° is a uniquely american thing - every city in europe has a naturally grown layout. Since the US doesn’t give a fuck about anyone else (as seen in the vote and their renaming stuff into <whatever> America) I also don’t give a fuck about what maps they use.
Edit 2: If you use your current position as the center of the projection, anything close enough to be relevant stays at 90° - or so close that i dare anyone to see the difference.
I was making maps as an intern for the city government, and my biggest problem was that the Mercator made the city look much wider than it really was.
I’m not sure about the 90 degree angle thing, but i wanted to point out that navigation is only one reason someone might use a map, and then agree with you that using a projection centered near the local area is probably going to be best 9/10 times.
I seem to have upset some mercator afficionados. As you say, for everyday usage any type centered on you (or a bit in front of your position) will be close enough to reality that navigating will be fine. For city planning the true size of things also matter a lot, as you mentioned. Long distance navigation doesn’t use paper maps anymore except when GPS is jammed (which is not the norm if you aren’t near Iran or Ukraine currently), and we are already on the way to make quantum navigation for ships feasable. In the case of aircraft, if GPS is down, there are more than enough alternative ways to navigate (communication with flight control, ground based beacons and so on) and long distance road travel will in 99% of cases use high tier roads which tend to have signs indicating where they go, in addition to navigation software that could adjust map projection on the fly if needed (but it isn’t really needed, what you need is accurate lane and turn information, which is independent of what you see on the display).
I really don’t understand the hive mind in this case. Anyone having some input here where the issue lies? I haven’t touched a paper map where any of this stuff had mattered at least since the turn of the century.
only when navigating, not when looking at the map
Do you really think that the distortion over the short distance shown while navigating matters? I don’t know many drivers that actually use their geometry kit when using a navigation app.
People use digital maps for all kinds of purposes, not just navigating while driving.
For example I often look at digital maps as a pedestrian in order to know which direction to walk (even without actually entering navigation mode), or in order to find out where places of interest are around me, and there it definitely helps that the angles are the same in reality as on the map.
How many different directions can you go in where the skewing of angles would cause you confusion?
I didn’t know you live so close to the arctic that you can’t identify the direction you need to go when looking at a paper map.
With navigation software that simply uses your current position for the center of the projection all corners stay so close to reality that i dare you to see the difference (we are not living on a globe the size of a tangerine). There’s also the hint you get from the small arrow pointing out the direction you are currently facing.
I’m fairly sure the software care a great deal about projections and which chart datum is used. Just because it’s abstracted and invisible for the user I’m fairly sure you would notice if google maps stopped accepting wgs-84 positions or if they changed into an inverted projection. So yes it matters a great deal even on local levels.