rainbowunicorns wrote:Do any of you have any useful sites on UTM? I’m trying to figure out how to find the UTM on a topo map but find it fairly confusing...
We have this clear square thing that’s divided into sections that’s supposed to help us find the UTM, but I have no idea how to use it.
Think of it like this:
You have your UTM tool right? You'll notice that it is split up into a 10x10 square. Now, Each small square is 100meters x 100meters, meaning the entire square is 1000meters x 1000meters. Not that complicated right?
Now, How are we going to use this to find coordinates on the map?
UTM is split into regions throughout the US, similar to the PLSS system, if you've ever seen that. There is a regional Equator and Meridian for each region (North and South lines of 0), and you can progress N,S,E,and W of this point, similar to longitude and latitude. Now, instead of measuring in degrees or minutes or such, UTM is measured in meters N,S,E or W of the meridians, so a fairly large number right?
If you look at your map, you will see numerous small numbers on the edges of the map. They look like 1-3 numbers subscripted, followed by two more numbers in regular font. It will look something like this:
3450 (except for the 34 would be up instead of down)
You'll see it for sure.
Now, this number tells us the distance from the 0 line; Equator if on the left or right sides of the map, and Meridian if on the top or bottom sides of the map. You also may notice, that on some maps, there is a black grid laid out in accordance to these numbers, but not all.
The next thing you may notice, is that each of these lines (or boxes on the grid) line up perfectly with your UTM tool, meaning the distance between each tick is 1000meters! Now, Keep in mind that these numbers aren't 1000 numbers apart in value, for every 1000m north south east or west of this mark, the number only changes by one.
This is because the UTM number on your map only goes down to the thousands place. If you want to express that value in meters, you must add three digits following those on the map, (Or simply follow each tick by 000 to get to individual meters). Using our example of
3450, we can decode this to be 3,450,000meters. Lets say this value was found along the top (and bottom) sides of the map, and the numbers were increasing as you moved west. This means that the
3450 value is 3,450,000meters West of the Meridian.
This is how you would write your UTM values.
If it asks you to find the UTM coordinates of a point within the map, this is where your tool comes into play. Align your tool with the UTM grid (You may have to "Make" one if the map doesn't have one), and then use the UTM tool to split your UTM square into 100meter intervals. This is fairly accurate as you may notice. Now, Add or subtract this hundreds value to the number on the edge (Remember to add 000 to those values), and indicate wether this UTM value is North South East or West of the Meridian or Equator it pertains to. An Example UTM coordinate looks like this:
3,450,460m W 3450 + your tool measurement (In this case 460 more meters West)
631,960m N 631 + your tool measurement (In this case, 960 more meters North)