Topo maps with lat and long grids.

[manfredvonrichthofen]

Task O-0204 requires the use of a topographical map with latitude and longitude grids. I am yet to find a map that is actually gridded in latitude and longitude. I have found maps, quite a few, that are gridded with UTM grids (universal transverse mercator). Has anyone been able to find a map that is gridded in lat and long?

I take back this question, because I realized the stupidity of it. There really is no way to accurately grid a round planet in lat and long on a flat plane.

Given this bit of a quandary though, how are you to get a good lat and long point on a map with only having a few points that are really marked in lat and long?

[Ed Bos]

USGS Topo maps have map symbols (think black + marks) that correspond to the lat/long markings along the sides.

You can use a straightedge and those symbols to draw out your lat/long grid lines.

[sardak]

Task O-0204 requires the use of a topographical map with latitude and longitude grids. I am yet to find a map that is actually gridded in latitude and longitude. I have found maps, quite a few, that are gridded with UTM grids (universal transverse Mercator). Has anyone been able to find a map that is gridded in lat and long?

O-0204 doesn't require topo maps. It states "Given an aeronautical chart, road map or topo with latitude and longitude lines."

In addition to the lat/lon tic marks along the borders, the face of the USGS topos have a + mark at each intersection of the tic marks along the sides.

DeLorme Gazetteers (some anyway) have lat/lon grids.

There was another thread on here about mapping software which you asked about. Those programs will draw lat/lon grids.

Sectionals and TACs have lat/lon grids.

I take back this question (too late ), because I realized the stupidity of it. There really is no way to accurately grid a round planet in lat and long on a flat plane.

Actually there are ways and cartographers have been using them for centuries. Are the lat/lon grids rectangular like UTM or MGRS grids? Normally not, because lines of longitude converge at the poles. However, maps can be drawn with parallel lines of longitude, though usually only for special maps.

Assuming you're using a 7 1/2 min USGS topo, the lines of longitude converge and therefore the left and right neatlines (map borders) are not parallel. If you measure the widths of the northern and southern borders on a USGS topo you'll find the north/top is narrower by a small amount. The actual difference depends on the latitude.

Given this bit of a quandary though, how are you to get a good lat and long point on a map with only having a few points that are really marked in lat and long?

It requires measurements and math. However, there are lat/lon "interpolators" that take most, but not all of the math out. I've attached to this message the set I use with instructions or you can get them from another source here:

http://maptools.com/FreeTools/LatLon.html

http://maptools.com/UsingLatLon/plotting.html

Mike

[EMT-83]

+1 on the DeLorme Gazetteer. Lat/long, topo and street map all in one.

Not as detailed as USGS, but it's the whole state in one book that's easy to carry.

[SARJunkie]

Why don't we teach and use US National Grid ?   

The USGS Website has Topos you can download with LAT / Long Grids.

[ELTHunter]

MyTopo.com enables customized maps.  Not only can you customize the areas you want mapped, you can specify which coordinate systems you want to see on the margins and grid lines.  For about the same price as buying a topo map in a store, you can design your own and they will mail it to you in about three or four business days.

[starshippe]

. . many years ago i used the delorme maps, but found them difficult because instead of having scale marks at an even minute or fraction of a minute, they would have marks designating something like 31 deg, 14.061875 minutes. interpolation was difficult at 2 a.m. i whined for a bit and stopped using them when i accidentally left mine at the fbo in savannah.
. . are the coordinates more useful now?

thanks
bill

[ol'fido]

Many years ago, I dusted off some of my high school drafting skills. I took a Delorme Atlas and some of the clear (brain fart) sheets for an overhead projector. Using a draftsmans triangle, t square, and an engineers ruler I made an overlay that could be xeroxed that covered about 15' lat and long on the map. Place it on the corner or one of the "+" marks on the map and you could get a pretty accurate lat and long reading. I think I saw those a couple of months ago in one of my folders.

Not saying it's better than one of the high tech computer topos you can get today but in the 90's it was high speed and low drag.

[manfredvonrichthofen]

Amazing Sardak!!! I forgot that those scales existed. :clap: :clap:

[EMT-83]

. . many years ago i used the delorme maps, but found them difficult because instead of having scale marks at an even minute or fraction of a minute, they would have marks designating something like 31 deg, 14.061875 minutes. interpolation was difficult at 2 a.m. i whined for a bit and stopped using them when i accidentally left mine at the fbo in savannah.
. . are the coordinates more useful now?

I have Gazetters for three states; they're gridded in degrees/minutes with slash marks for seconds. Not sure if others may be different.

[starshippe]

. . will be getting one for the plane, one for the van, and one for me.

thanks for the note,
bill

[sardak]

Amazing Sardak!!! I forgot that those scales existed.

Glad to be of assistance.

Many years ago, I dusted off some of my high school drafting skills. I took a Delorme Atlas and some of the clear (brain fart) sheets...

I did something similar in the early 90's but used a "computer aided" drafting program to draw 7.5 minute grids with lines at 15 second intervals. Since the grid sizes change going north to south, I fit 4 grids to a 8.5 x 11  brain fart acetate sheet with a code telling the user which of the four grids to use for which page range in the book. We're still using them with the Gazetteers.

. . many years ago i used the delorme maps, but found them difficult because instead of having scale marks at an even minute or fraction of a minute, they would have marks designating something like 31 deg, 14.061875 minutes. interpolation was difficult at 2 a.m.

...delorme has changed over the years. the earliest one in my stack is 1986 and it only has tic marks every 7.5 min. this made it easy to draw CAP grids and match the grids to topo maps. then in the mid to late 90's delorme started putting tic marks every one minute (which is still the way it is on my most recent ones). there are still tics every 7.5 minutes.  the marks are labeled with grid lines across the maps every 5 minutes in my current state version.

...i have a 1997 kansas edition which reflects your gripe - the longitudinal grid lines are labeled at 7 minute intevals and the latitude lines are labeled every 4 minutes 15 seconds, even though the tic marks are every minute.

Why don't we teach and use US National Grid ?

We're going to have to at some point. At one time there was task O-0208, locate a point on a map using UTM, required for UDF and GTL, but it was dropped between the 2001 and 2004 SQTRs.

Mike

[Spaceman3750]

They still teach UTM at NESA. Quite frankly, it is WAY easier, more practical, and more accurate than using lat/long. The problem is that everyone is familiar with lat/long and not as many with UTM - it's really a regional thing whether or not the person on the other end of the radio will know what I'm talking about if I give him my grid.

[davidsinn]

They still teach UTM at NESA. Quite frankly, it is WAY easier, more practical, and more accurate than using lat/long. The problem is that everyone is familiar with lat/long and not as many with UTM - it's really a regional thing whether or not the person on the other end of the radio will know what I'm talking about if I give him my grid.

I'm going to stick with Lat/Lon because all of my devices recognize it. I can plug a coordinate into my phone and pull sat images or drop it into my Tomtom and get driving directions right to it. I can't do that with UTM.

[Eclipse]

They still teach UTM at NESA. Quite frankly, it is WAY easier, more practical, and more accurate than using lat/long. The problem is that everyone is familiar with lat/long and not as many with UTM - it's really a regional thing whether or not the person on the other end of the radio will know what I'm talking about if I give him my grid.

No one in a CAP mission base will have any idea what you are talking about if you start sending UTM numbers.  Lat/Long is universal, simple, and everyone knows how to use it.

If you're going to use UTM, you might as well break out the artillery compasses with mils radian, too.

[NIN]

+1 on the DeLorme Gazetteer. Lat/long, topo and street map all in one.

Not as detailed as USGS, but it's the whole state in one book that's easy to carry.

Yeah, and years ago (not sure, haven't done it in awhile) it was really easy to take a highlighter and a straightedge and throw the CAP grid onto a Gazetteer.   Took me a couple hours, tops, on an NH Gazetteer. 

And I seem to recall the last one I bought had UTM grid on the edges. I could be wrong.

But for something to toss in your ground team vehicle, you cannot beat those for coverage, detail, relief, and overall usability.

[SARJunkie]

We need to learn it.  FEMA/DHS and the National SAR Supplement have mandated use of USNG for ALL responders!

If we don't learn it we will be kicking ourselves.

Another way CAP can become 'interoperable' with others.

[SARJunkie]

+1 on the DeLorme Gazetteer. Lat/long, topo and street map all in one.

Not as detailed as USGS, but it's the whole state in one book that's easy to carry.

Yeah, and years ago (not sure, haven't done it in awhile) it was really easy to take a highlighter and a straightedge and throw the CAP grid onto a Gazetteer.   Took me a couple hours, tops, on an NH Gazetteer. 

And I seem to recall the last one I bought had UTM grid on the edges. I could be wrong.

But for something to toss in your ground team vehicle, you cannot beat those for coverage, detail, relief, and overall usability.

LAT / LONG is NOT universal.

there are three formats of Lat/Long.  When the State Police use one, CAP uses another, local sar uses the third.  How is that universal?

You can look up many AAR's from FAA when response was delayed several hours because unlike Lat/Long formats between responders.

USNG IS Universal!

[Spaceman3750]

+1 on the DeLorme Gazetteer. Lat/long, topo and street map all in one.

Not as detailed as USGS, but it's the whole state in one book that's easy to carry.

Yeah, and years ago (not sure, haven't done it in awhile) it was really easy to take a highlighter and a straightedge and throw the CAP grid onto a Gazetteer.   Took me a couple hours, tops, on an NH Gazetteer. 

And I seem to recall the last one I bought had UTM grid on the edges. I could be wrong.

But for something to toss in your ground team vehicle, you cannot beat those for coverage, detail, relief, and overall usability.

LAT / LONG is NOT universal.

there are three formats of Lat/Long.  When the State Police use one, CAP uses another, local sar uses the third.  How is that universal?

You can look up many AAR's from FAA when response was delayed several hours because unlike Lat/Long formats between responders.

USNG IS Universal!

You tell each other which datum you're using.

Eclipse, I agree with you. I don't think it's good that mission base staff don't work with UTM, but I agree that they don't. That's why I know both.

[SARJunkie]

the problem is, if the other agencies dont know what 'datum' that they use, how do we know?  example.

Last REDCAP I Ic'd:

Local sheriffs office gave us coordinates in  Lat/Long    in the  dd.dddd format:
27.4657  -82.2134
After confirning they wer degrees decimal, we sent a team to the area.

found it to not even be in thier county.

What they meant was
27 47.57    82 21.34  degrees min.decimal min
Over 22 Miles away. and a seperate format. 


So even when we confirmed the format was 'correct' they still were not.  and the mission was delayed several hours!

So again.  How is that standard.

USNG is the Standard? why dont we jump on board?