What are they?
How do you interpret them?
What do they tell us?
and what can we do with them?

For starters.

I know some of the answers but would like to encourage some discuss from our members in the know to provide info for those of us who don't know much about them.

I know they tell us a location but?

Thanks guys and gals.

To my wife the only important coordinates would be do these shoes go with that dress?.

I do not use them but I know there several different systems. Some better suited to particular uses. Surely there are a few GIS users here who understand which is most common and why.

Lets say someone wants you to go to a specific location and sends you the coordinates instead of specific directions.

Well, one coordinate system is latitude and longitude. Using those to numbers you can get a reasonably precise location if there is enough precision in the lat/long you are given. There are multiple other coordinate systems, but without knowing which coordinate system the coordinates you were from it may be more challenging to nail exactly where the location is.

If someone sent me their lat/lon to me, I’d just pop it into Google Maps.

Years ago, I had an old handheld GPS. If it had any map, I don’t remember. If so, it was VERY rudimentary.

I would use online maps with a coordinate function where your curser pointer showed real time coordinates. That was pretty fancy back then. I would input those points on a map, and my gps had an arrow which would guide me to that point.(over time, the online sites were wikimapia.org and maptechserver. No idea if they are still functioning)

One day, I got a call of a stolen truck tractor/semi-trailer combination in the area of our truck stops. Knowing trucks started being tracked by gps, I had dispatch get the coordinates from the trucking company.

Shortly thereafter, I got the coordinates and located the “stolen” vehicle at a wrecking yard in the area. It turned out that that basic procedure was a first for my agency, and it wouldn’t have happened without my personal gps and initiative.

I have since done many times more with newer gps receivers and with our MDT systems. To add, about once every month or two, we’d get an “ATL a stolen vehicle” call from companies like SIRIUS/XM. Every time, their coordinates never helped us to locate a vehicle. Why them? I have no idea.

I just spent about 3 months working on a project at work, updating lat/long on oilfield assets in our system.

They're not on roads, so Google maps won't get you there [reliably], but there are a few specialized oilfield apps that navigate unnamed lease roads.

We went from thousands of assets with 0.0/0.0 [which is off the west coast of Africa], to giving TX & its surrounding states the weasels with GPS pins.

PA State Parks make good use of coordinates. Here is an example from the website of my favorite park:

From I-76, take Exit 110 (Somerset) and drive west on PA 31 from Somerset for eight miles. Turn left onto Trent Road and follow the directional signs to Laurel Hill State Park.

The park may also be reached from Exit 91 (Donegal) of I-76 by turning left on PA 31 east and traveling 14 miles. Turn right onto Trent Road and follow directional signs to the park.

GPS DD: Lat. 40.01023 Long. -79.2244

This is how to read the coordinates.

• First number (Latitude): Measures north (+) or south (-) from the Equator (between -90 and 90).
• Second number (Longitude): Measures east (+) or west (-) from the Prime Meridian (between -180 and 180).
• Order rule: Always latitude first, longitude second.

This is how it would look when entering into something like Google Maps or a Garmin GPS: 40.01023,-79.2244

There are converters that change digital coordinates to Degrees, Minutes, Seconds so they look like this: N 40° 0' 36.828'' W 79° 13' 27.84''. This is handy for paper maps and charts (remember those?)

If you "drop a pin" in Google Maps, the digital coordinates can be copied and shared. Mighty handy if one needs emergency assistance.

Astronomical coordinates?

Astronomical coordinates are a set of reference systems that describe the position of celestial objects on the “celestial sphere” using angles, much like latitude and longitude describe positions on Earth.

How They Work

Just as Earth’s latitude and longitude define a location on our planet, astronomical coordinates define the direction of an object in space relative to a chosen reference plane and point. The “celestial sphere” is an imaginary sphere centered on the observer, onto which all celestial objects are projected.

Two angles are used:
• Latitude-like coordinate: angular distance from a reference plane (e.g., celestial equator).
• Longitude-like coordinate: angular distance along a circle from a reference point (e.g., vernal equinox)

Main Astronomical Coordinate Systems

Horizontal (Alt–Az) System
Reference plane: Local horizon.
Coordinates:
• Altitude (a): angle above the horizon (0°–90°).
• Azimuth (A): angle along the horizon from north (0°–360°).
Use: Directly tied to the observer’s location and time; changes with Earth’s rotation.

Equatorial System
Reference plane: Celestial equator (projection of Earth’s equator).
Coordinates:
• Declination (δ): latitude on the sky, –90° to +90° (0° at celestial equator).
• Right Ascension (α): longitude on the sky, measured eastward from the vernal equinox, in hours, minutes, seconds (1h = 15°).
Use: Fixed relative to Earth’s rotation; standard for star catalogs.

Ecliptic System
Reference plane: Ecliptic (Earth’s orbital plane).
Coordinates:
• Ecliptic latitude (β): angle above/below the ecliptic.
• Ecliptic longitude (λ): angle eastward from the vernal equinox along the ecliptic.
Use: Useful for solar system dynamics and seasonal astronomy.

Galactic System
Reference plane: Galactic plane (Milky Way’s disk).
Coordinates:
• Galactic latitude (b): angle above/below the galactic plane.
• Galactic longitude (l): angle eastward from the galactic center.
Use: Studying the Milky Way and extragalactic objects.

Why Multiple Systems?
Different systems suit different purposes:
• Horizontal for real-time observation from a site.
• Equatorial for fixed star positions and telescopes.
• Ecliptic for planetary and solar motion.
• Galactic for Milky Way structure.

In short: Astronomical coordinates translate the vast, shifting sky into precise, measurable positions, enabling astronomers to locate and track objects consistently across time and space.

This message has been edited. Last edited by: 229DAK,

Assuming the question is about geographic coordinates, although I know how to use the more common latitude and longitude coordinates, I much prefer working with UTM coordinates that the US military normally uses. The more detailed the (accurate) coordinates are, the more precisely one can determine a location. With enough UTM numbers, a location can be described to within 10 meters.

If we have the coordinates of something we’re supposed to find either on a map or on the ground using a map or GPS receiver, that’s the information they provide.

If we’re on the ground with a GPS receiver that gives us the coordinates of our location, they can be used to tell us where we are on a map. That can be useful if we’re in the woods trying to determine how to get to something like a road intersection: the direction to travel and how far it is.

That’s how it would work if someone gives us their coordinates and we want to go to them. We find our location on a map and then locate the position of the coordinates we were given. Once we have those two locations we use the map to determine the direction of travel necessary and how far we’ll have to go.

The most recent way I used geographic coordinates was to mark the boundaries of a proposed shooting range in a wooded area. I first obtained the coordinates from Google Earth, and then by entering the coordinates into my Garmin GPS receiver the device directed me to each spot on the ground so I could mark them.

Map reading and use is a complex subject, but that’s a brief explanation of what coordinates are about. There are books and Internet videos that explain things in more detail. In short, though, geographic coordinates, lat/lon, UTM, or something else, are to permit converting a map location to the ground (or water) or to convert a ground location to a map.

As others have noted, though, most people these days do not rely on actual maps, but allow our AI protectors to determine it all for us.

quote:

If someone sent me their lat/lon to me, I’d just pop it into Google Maps.

Good answer ftttu. It directly addresses Old Rugged’s second post.

With Car Play that would also give you driving directions.

You got to coordinate

quote:

What are they?
How do you interpret them?
What do they tell us?
and what can we do with them?

A way of describing a particular place, using pre-determined references

You don't. You ask an application to interpret them.

Typically, a spatial relationship from one coordinate pair (or trio) to the references

You might use them. For instance, calling in a fire mission to the artillery battery you would give coordinates. Sometimes these are simple map referenced grid squares. Other times, these are absolute locations relative to satellites. It depends on your need.

In a simple example, a men's ministry challenges participants to go to a place that normally would be described as 1234 Main Street. But, to enhance the experience, the latitude and longitude are given. Those who don't show self-initiative, diligence, persistence, and gumption never make it to 1234 Main Street for the meeting.

There’s also the easting, northing, or X,Y coordinate system. Commonly used in surveying, it assigns a position on a flat grid.

quote:

Originally posted by 4MUL8R:
In a simple example, a men's ministry challenges participants to go to a place that normally would be described as 1234 Main Street. But, to enhance the experience, the latitude and longitude are given. Those who don't show self-initiative, diligence, persistence, and gumption never make it to 1234 Main Street for the meeting.

Also consider that with a proper map, making your way to a specific set of coordinates (lat/long or Section-Township-Range) can still be done by finding an alternate route should the directions be unusable (trees down along the road for example).

I took a map reading / GPS course from the USGS 10 - 15 years ago. They taught me how to use the UTM system for reading the USGS maps. WAY EASIER than lat/long.

USGS topographic maps use a 1,000-meter grid system based on the Universal Transverse Mercator (UTM) projection, which aligns with the U.S. National Grid (USNG) standard.

MGRS + HAE elevation if you want an exact spot on the parts of our earth most people use.

Question for anyone who uses underwater coordinates: is depth measured exclusively off MSL or are other paradigms used as we do with height?

Another big lat/lon use is the pastime of geocaching. I got my wife and daughter into geocaching years ago, and I even got some fellow officers into it.

Many if not most of Texas LEOs use an online system(C.R.I.S.)to complete and submit traffic crash reports. It has been a while now that lat/lon have been required to identify the location of the crash.

Afgooye.
Its a coordinate system. Seriously.