CalTopo

It's funny, if I do a simple search for "boydsmaps.com" it unconvers quite a lot of social media posts (many are from the facebook "LIDAR and aerial archaeology" group) where people are recommending both caltopo and boydsmaps as their favorite sites, and each seems to have sort of its own "fan club"

Frankly, I had never even heard of Caltopo, so there never was any intention to "compete" with them and my site is completely free with no ads and no registration, so we are very different in that regard. But it still comes up in comparisons. You can do your own ai search, like "compare boydsmaps to caltopo" and it produces some interesting results that seem pretty accurate to me. But I think I'm doing pretty good, operating on zero budget (beyond the server lease, and a ridiculous amount of time spent writing code and making maps!) But caltopo sounds like a good resource for people. I have seen the complaint that it can be too confusing though. Some also say that about boydsmaps, to be fair (I will soon introduce a new search app to address some of that). If you're in my core coverage area (northeast US) you might wonder whether $50/year (or more?) for caltopo is worth it. But, of course, that's a personal decision which has a lot to do with what you expect and need.

BTW, talking about zooming to "200 feet" or "30 feet" is pretty meaningless and is classic for a seasoned Garmin user. I was the same until I started making maps and understood things like resolution. What does "30 feet" actually *mean*? Is this just like a Garmin GPS, where it shows the so-called "scale" on the screen? That literally means nothing, it's just a unit they put on the scale. You could put a scale that went up to 60 feet or 120 feet on the same map and it would be equally valid. It's just not a standard, and not useful for comparing different map sites (unless they have some irrational devotion to garmin).

What matters is the actual *resolution* of the map. With digital, that is very simply expressed as a value for how large each pixel on the screen would be in the real world. So, for example, if a map has a resolution of 4 feet, then each little dot (pixel) on your screen would be a 4 foot x 4 foot square in the real world. That actually tells you something useful - if your house is 40 feet by 60 feet, for example, then it would represented by a rectangle of 10 x 15 pixels on the map. That is actually pretty good when you think about it, your own little house "owns" 150 pixels of that map!

4 feet is the maximum resolution of the maps on my own server, because the amount of storage needed for higher resolutions gets (literally) astronomical. Another important concept here is that maps are two dimensional objects with height and width. So, if you double the resolution to 2 feet (higher resolutions mean fewer feet per pixel) you might think the map would require twice as much disk space to store. But that would be wrong, it actually requires 4 times the disk space because the width is twice as big *and* the height is also twice, so 2 x 2 = 4. This is an important basic concept.... area is a "squared function".

Now, imagery with 1 foot resolution is common today. A map at that resolution requires 16x as much storage as a map with 4 foot resolution! That gets very expensive, and is something that only big companies and government agencies can afford - not old retired guys on Social Security like me!

As you can see from that "rant", this is a bit of a "pet peeve" for me, but the message can be useful for you. To really compare maps, you need to learn a bit about resolution and not base your decisions on some artificial metric like "map scale" which has no standards and can mean whatever some company wants it to mean!

Just did a very quick side-by-side comparison with my site and a map in Garmin Basecamp. Their map scales are not an exact match for the standard web mapping resolutions, butI think that 4 foot resolution is roughly comparable to a 80 foot map scale in Basecamp while 1 foot resolution is pretty close to Garmin's 30 foot scale.

Now - think about that - it's highly unlikely that any maps you are viewing at the Garmin 10 foot scale have much accuracy. That is an extreme zoom level and you reach the point of "garbage in, garbage out". Now, it might help you see details when you blow things up that big, but you are unlikely to get more accurate coordinates.

It's been awhile since I dug into the details of Garmin's map format, but IIRC, the maximum resolution that their format supports is 3 meters (about 10 feet), due to the number of bits used to store coordinates. Anything beyond that is "overzooming" (which is something older Garmin devices and software warned you of).

Now, you also have to understand that "resolution" and "accuracy" are two completely different things too. A map can have a resolution of 1 foot, but that doesn't mean it's any more "accurate" than a lower resolution map. That depends on the quality of the data that was used. Again - garbage in, garbage out. Making the resolution higher doesn't help if the map was made in a way that isn't very accurate!

Probably not related but there is a system where the entire globe has been divided into 3 meter x 3 meter squares. Each individual square is then given a 3-word name. The details of the system can be found at https://what3words.com/clip.apples.leap. As an example, a restaurant named Bloom Southern Kitchen in Chester Springs PA has an “address” of typist.schoolyard.fashionable.

The system is used in many European countries by police, fire, and rescue organizations. It is particularly useful to pinpoint callers in remote areas or large parks where traditional addresses fail. Delivery drivers and postal services also use it to find exact drop-off locations or hard-to-find building entrances. Some car navigation systems (like Mercedes Benz) integrate the system into their car navigation system, and mapping tools integrate the 3-word addresses directly into their software.

Fascinating... never heard of that. Doesn't make much sense to me in today's world where coordiniates tell the whole story and can be represented with about the same number of characters. But I get it, this is supposed to be something that humans can remember. Good luck with a long list of waypoints though, that might look rather ridiculous IMO.

Personally.... I'll pass, but it's certainly interesting!.

If you put an address into the what3words app, say my example of typist.schoolyard.fashionable, then click the black Navigate button you can directly export the location into Google maps for directions. This can also be done with Waze although I do not know the exact steps since I don’t use waze.

The military uses the MGRS coordinate system that can have a resolution down to 1 meter. See the link below for content on how it works. For my previous example the MGRS coordinates would be 18T VK 41299 36661.

https://maptools.com/tutorials/mgrs/quick_guide?srsltid=AfmB...

This is all somewhat related to my current search app (coming soon, hopefully...). The app stores a full database of US POI in your browser, for super-fast searching and complete privacy (nothing is sent back to the server). I am trying to keep it lean and mean, so have pondered how many decimal places were needed in the coordinate fields. Might seem trivial, but my current database has 165,000 POI and will probably expand to 200,000. Each decimal place would add 400,000 bytes to the database.

I worked out the precision based on decimal places, it's a little different depending on where you are and x / y resolutions aren't quite the same, but just to round it off:

3 decimal places: 100 meters
4 decimal places: 10 meters
5 decimal places: 1 meter
(etc...)

IIRC, Garmin handhelds display 5 places, don't they? I use 6 places for links, but full floating point math internally.

I have never used MGRS myself, but that's an interesting link.