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? 

[LTC Don]

North Carolina at the state level is USNG, as hopefully are most states. 

During a recent missing person exercise using canine teams, and team members using handheld GPS devices, we had a challenging time with teams calling in coordinates in lat/long and utm.  One team in particular had a hard time configuring the device to give the correct level of utm down to their actual position.  So, even the civilian sar groups are still learning the technologies.  Paper still ruled when it came down to the final analysis.

Canine teams are a unique challenge since the dog dictates the route and speed of travel, making it near impossible to keep up with bearings and pace count.  There are now gps units that can be affixed to the dog with rapid setting waypoints to fully track a dogs complete track.

CAP needs to be teaching GPS technologies, lat/long, and USNG/UTM.  There shouldn't be any discussion at this point in our evolution and this being 2011.  UTM has been around a very long time, and the civilian SAR community has been using it for quite a good while now.

[Ed Bos]

The AKWG is using GARS to identify search grids, since the 11th RCC is passing information to us that way.

At the NESA GTL school we're teaching Lat/Long, UTM, and briefly touching on GARS (since we're time-compressed as it is we can only mention it, really) and the CAP grid system (since the latter is in the task guide).

Just food for the conversation.

Does anyone have any best practices, or techniques that they can verify are especially useful?

[SARJunkie]

Any modern GPS that supports MGRS (Military Grid Reference System) will work with USNG, by simply switching the Datum from WGS84 to NAD83.

Now you display USNG vs MGRS.

So to convert a lat long to USNG, you simply change the coordinate system and datum back and forth on your GPS.

[starshippe]

. . there are several conversion routines available, but the delorme topo software will let u select from, and convert between.....

. . deg, deg.min, deg min sec, utm/ups, mgrs, usng, and spcs.

. . i've been expecting the af to throw a set of utm coordinates at us during an evaluation for a decade or so. my guess is, its not going to happen.
. . if u find the utm conversion excel spreadsheet written by steve dutch, let me know and i will give u a fix for a rounding problem it has. 

73,
bill

[Major Lord]

Drawing lat/long accurately on a 2 dimensional map would be simple if the earth was a sphere.......unfortunately, its an Ovoid Sphere. I blame global warming .

Major Lord

[Eclipse]

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?

It's universal in regards to consumer-level devices, which is for the most part what you are going to see on CAP missions - other agencies can
use whatever they want, issued or otherwise, but most smartphones, handheld GPS's, and similar devices can decode LAT / LONG in whatever format
is specified.

This continued notion that one agency will report in one format and another will report in a different one is silly.  As space said, The IC simply specifies the format.  If you can't coordinate something simple like that, you're cooked on anything bigger.  Do we just throw up our hands on radio frequencies when the mission calls for inter-agency cooperation?   Of course not - we either give the other agency the freqs they need (in exchange for a kidney),
get them from them, or hand them a compliant radio and show them the on switch.  Same goes for GPS's.

Further, in terms of accuracy, as a reminder, we train and operate in a +/-5 degree world.

It is amazing the lengths that people will go to justify doing thing the hard way because it is "better".

The next thing we'll get is a suggestion that we better wholescale abandon handheld GPS's with moving map displays and cellular phones with data capabilities because "...in the big one they won't work, and POTUS could take out the birds during an insurrection..."

While you're gridding your charts by hand and putting up the masts, I'll be over here trying to find the missing people.  Want to know where I am?
Join my Latitude circle and track me in real time, or I can hit the "I am here" button and send you my coordinates and a link to a Google map.

[Eclipse]

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!

A good GBD / IC should be tracking the teams in real time - I don't send anyone anywhere until I confirm that
the coordinates make sense.   Why would you send a team without looking at a map?

[SarDragon]

Drawing lat/long accurately on a 2 dimensional map would be simple if the earth was a sphere.......unfortunately, its an Ovoid Sphere. I blame global warming .

Major Lord

The conic projections used on sectionals and TACs do pretty well. I've checked out known locations on a sectional against my GPS (the one I got from Ian, AAMOF) and there is pretty close agreement. Same for de Lorme Gazetteers.

[SARJunkie]

Again,  Everyone else uses USNG.  How are we to inter-operate with them if were not on the same page?

USNG is a capability of any modern GPS!

[starshippe]

. . the gps enabled 406 mhz elts and epirbs are reporting their position in latitude and longitude.

bill

[SARJunkie]

This again brings up the issue of "The CAP bubble"   as long as we are only working with ourselves, we are ok.  But knowbody wants to break the 'bubble' and interoperate with others.   As soon as we start to play with other agencies we MUST learn the standards outside of the 'CAP Bubble'

[Eclipse]

Again,  Everyone else uses USNG.  How are we to inter-operate with them if were not on the same page?

USNG is a capability of any modern GPS!

Define "everybody"...

Because I can tell you that "everybody" with a GPS is capable of Lat / Long, but not "everybody" even knows what USNG even is.

That doesn't mean we shouldn't be aware, but it also doesn't mean we start changing our ops just because we "might" work with an agency that uses it.  Give me proficient members in the field and air that are just capable of reporting their position accurately in LAT / LONG (vs "12 miles from the VOR" or "by the McDonald's at Main and 6th") and the rest can be converted as needed by the branch directors, since position reports and tasking orders should be going through the ICP, not direct between teams anyway.

I had a conversation last night with my CD who just got back from a planning meeting regarding a region-wide
exercise (real-world, non-CAP directed), and I can tell you, as most of us know, that just because an agency or group is city/state/fed funded, doesn't mean they have their act together any more than CAP does, and in a lot
of cases, especially in terms of coordinated response and use of ICS, CAP is the best-trained, most experienced asset in the room.

For all that sentence means in every direction...

[SARJunkie]

At least in the South East US most agencies have transitioned to USNG.  It is mandated by FEMA.  Again, if we want to play nice with others we need to learn it.

Not everything is coordinated through the GBD.  A team in contact with lets say Fish and wildlife needs to coordinate and converge on a location.  The two teams can talk to each other. If FW uses USNG, how is the CAP Ground Team they are talking to navigate the the convergance point?

During a disaster CAP is asked to checkout a target ,  wich is givin in USNG. 
Why would we convert it, introduce error, and extra time?  makes no sense!

[chief2]

During Deep Water Horizon (DWH) all products located, boom locations) was given to the USCG in lat-lon format, at their request and this was in the SER.

[Larry Mangum]

So that makes sense that in SER you might need to use USNG. Out west, where you might be working for a state agency which uses just plain old lat and long, it would not make sense.   The important thing is that the wing be able to provide it's customers the data they requested or need.  Let's not try to mandate a change across all of CAP that may cause more of a problem then it solves.  Yes, FEMA may mandate it, but it took a presidential executive order just to get everyone down the path to NIMS compliance. How has that worked out, is every one on the same page now?

[sardak]

Too bad you clarified "everyone." I had a huge stack of cash ready to bet against that.

USNG was adopted as a federal standard in 2001, before the Shuttle Columbia search, Katrina, Rita, etc. It wasn't the common method used on any of them. After Katrina, the National SAR Committee was tasked with coming up with a common system for SAR. At that time the SAR world "discovered" USNG. NSARC and FEMA had no choice in what to declare the standard. However, their policies only apply when the feds are in charge of an incident.

This is from the published Catastrophic Incident SAR (CISAR) supplement to the National SAR Supplement and this same wording is in the draft Land SAR supplement to the NSS.

- Land SAR responders use U.S. National Grid; however, a good familiarity with latitude and longitude is necessary to ensure effective interface between Land and Aeronautical SAR responders (Note: Land SAR includes SAR on flooded terrain).

- Aeronautical SAR responders will use latitude and longitude for SAR response. However, aeronautical SAR responders that work directly with Land SAR responders should understand the U.S. National Grid system for effective Land SAR/Aeronautical SAR interface.

- Air space deconfliction will only be implemented and managed using latitude and longitude.

- Aeronautical SAR responders working with Land SAR responders have the primary responsibility of coordinating SAR using USNG. However both groups must become familiar with both georeference systems.

As for GARS, it's an area reference system, not a point reference system, and is only used for airspace management.

For the above visit: http://www.uscg.mil/hq/cg5/cg534/nsarc/Georeferencing_info.asp

By international conventions, the aeronautical standard for position reporting and Cospas-Sarsat locations are latitude and longitude.

In the US, the Sarsat messages automatically generated and sent to the RCCs have the positions in lat/lon to a tenth of a minute resolution. This isn't going to change. Perhaps in the future the RCCs may have the controllers convert the lat/lon to USNG, but that would be a mistake.

Any modern GPS that supports MGRS (Military Grid Reference System) will work with USNG, by simply switching the Datum from WGS84 to NAD83.

Having someone switch between NAD83 and WGS84 is an unnecessary step that leads to potential errors by the user accidentally switching to the wrong datum. NAD83 and WGS84 are considered equivalent because the max position difference between them is only about 2 meters, well within the accuracy of anything SAR is doing.

This is the exact same point, to the same resolution of 1 meter.
13S ED 05529 64533  USNG-NAD83
13S ED 05529 64533  MGRS-WGS84
13S 0505529  4364533  UTM-NAD83 or WGS84

What is important though is that many, many topo maps are drawn to NAD27. The differences between NAD83/WGS84 and NAD27 when using USNG/MGRS/UTM can be a couple of hundred meters. This may or may not be a big deal depending on what the coordinates are being used for.

All that being said, I'm in favor of using USNG/MGRS/UTM, since UTM has been used in SAR for decades, though not everywhere. It was a CAP task at one time but was dropped. However, we still have to know and use lat/lon.

Mike

[SARJunkie]

During Deep Water Horizon (DWH) all products located, boom locations) was given to the USCG in lat-lon format, at their request and this was in the SER.

The florida portion of the mission was in USNG!

[Spaceman3750]

During Deep Water Horizon (DWH) all products located, boom locations) was given to the USCG in lat-lon format, at their request and this was in the SER.

The florida portion of the mission was in USNG!

So the rest of the states were on one system and Florida was on another? That makes very little sense.

Also, you might want to stop using exclamation points after every sentence with USNG in it. Otherwise I'm going to expect that you will start calling USNG magical and revolutionary^TM.

[SARJunkie]

the reason being is, after about 4 days when every agency involved was using a difirent coordinate system , Florida got smart and everyone went to USNG!!!!!!!!!!!!!!!

[chief2]

All the Florida aircraft that were working the gulf gave me the reports in lat and lon. which I relayed to their command center in lat and lon, I was the CUL and MRO for 113 days, so I know how the reports came in from Florida.

[SARJunkie]

The Florida side of the mission, when they reported the targets via the State 800MHz system were in USNG. all FL operations were in USNG.

[chief2]

That was if the 800mhz worked, which most of the time it didn't because they called me on the Daphne Rpt and gave me all their reports in lat and lon. So not all Florida operations were using USNG, All aircraft from GA, AL, La, MS, NC, FL, and GLR gave me their reports in Lat and Lon.

[Eclipse]

Don't you love how facts get in the way of assumptions?

[SARJunkie]

wow...

[Spaceman3750]

... everyone went to USNG!!!!!!!!!!!!!!!

Today I'm here to talk to you about USNG. Quite frankly, it's simply magical and revolutionary^TM.

Sorry, I had to do it.

[chief2]

There have been many reports in Electronic/radio mag. about the failure of the 800 mhz systems, when it is used in the area of long neddle pine trees, the neddle's appear to set up a harmonic in the 800 mhz range, killing the use of the system. A private amb. service in Lower Al (RM) attempted to use it, it was a total failure and had to resort to the use of a VHF system.

[Eclipse]

... everyone went to USNG!!!!!!!!!!!!!!!

Today I'm here to talk to you about USNG. Quite frankly, it's simply magical and revolutionary^TM.

Sorry, I had to do it.

You win - epic - seriously!

[SARJunkie]

There have been many reports in Electronic/radio mag. about the failure of the 800 mhz systems, when it is used in the area of long neddle pine trees, the neddle's appear to set up a harmonic in the 800 mhz range, killing the use of the system. A private amb. service in Lower Al (RM) attempted to use it, it was a total failure and had to resort to the use of a VHF system.

yes, because there are soo many pine trees 5 miles off shore!

[chief2]

I take it your command center was also 5 miles off shore

[SARJunkie]

what does pine needles have to do with Comms and USNG Lat Long?   Im not trying to be a smart ass...  just currious

[chief2]

If you read the prev post about using the Foresty 800 mhz system, you would understand why it does not work around long neddle pines trees.  That is why almost all of FD and PD depts are leaving the 800 mhz systems in the south where there is a lot of long neddle pines and moving to the 700mhz systems. and that is why it did not function properly during dwh and the Florida aircraft diverted back to using an established vhf rpt system, All aircraft in the dwh mission, FL, AL, GA, Tn, La, Ms, NC, and GLR all used the standard lat lon system per the request of the US Coast Guard. and I have that on the work sheets they sent out. Also all vessels working the spills and booms used the lat lon system as I had constant communication with them also

[SarDragon]

To add more - pine needles contain a significant amount of moisture, which conducts electricity. I measured the resistance of several 3" long pine needles, taken at random directly from the tree, and the end-to-end resistance was about 4 megohms.

The wavelength for 800 MHz is 14.8", so one of these needles approaches being 1/4 wavelength, and a potential antenna.

The Navy had significant problems with the radars on their maritime patrol/ASW a/c early on because of "salt return". The salt spray over the ocean would cause a significant return on radars tuned to frequencies having wavelengths in the neighborhood of multiples of the dimensions of airborne salt crystals. Retune the radars - problem goes away.

YMMV.

[chief2]

Pine neddles down here on the coast run an easy 14" in length

[Spaceman3750]

To add more - pine needles contain a significant amount of moisture, which conducts electricity. I measured the resistance of several 3" long pine needles, taken at random directly from the tree, and the end-to-end resistance was about 4 megohms.

The wavelength for 800 MHz is 14.8", so one of these needles approaches being 1/4 wavelength, and a potential antenna.

The Navy had significant problems with the radars on their maritime patrol/ASW a/c early on because of "salt return". The salt spray over the ocean would cause a significant return on radars tuned to frequencies having wavelengths in the neighborhood of multiples of the dimensions of airborne salt crystals. Retune the radars - problem goes away.

YMMV.

I understand that 1/4 wavelength is ideal for an antenna, but does it HAVE to be 1/4 wavelength to become an antenna?

[SarDragon]

Not at all. Multiples of 1/4 wave work just as well. I was just pointing out the reasoning behind that particular problem. I thought I clarified the multiple wavelength part when I discussed salt return.

[SARJunkie]

First off, the system is NOT a forestry system.  Being a professional RF guy, why would forestry even  use 800? that's kind of stupid!

The problem with the 800 system in deepwater, is the crews couldn't follow directions.  there were several other agencies using portables in aircraft that had no problem with the system. 

The system uses both 800 and 700, so your theory of 800 pine needle interference would not apply here.

I routinely flew 30+ miles offshore with an 800 portable in a Cessna or helo, and had no problems.

When you spend 30 min with the crew, give them a 'cheat sheet' on the radio and them have them demo it to you, you would think that they would understand.  approx 40% of the crews just couldn't handle it!

Its not an issue of propagation, or RF, or the system not working.  its 100% operator error.

I can also tell you for a FACT that the coordinate system used on the 800 system was USNG, for the "State Mission"

[ammotrucker]

If you read the prev post about using the Foresty 800 mhz system, you would understand why it does not work around long neddle pines trees.  That is why almost all of FD and PD depts are leaving the 800 mhz systems in the south where there is a lot of long neddle pines and moving to the 700mhz systems. and that is why it did not function properly during dwh and the Florida aircraft diverted back to using an established vhf rpt system, All aircraft in the dwh mission, FL, AL, GA, Tn, La, Ms, NC, and GLR all used the standard lat lon system per the request of the US Coast Guard. and I have that on the work sheets they sent out. Also all vessels working the spills and booms used the lat lon system as I had constant communication with them also

First off cheif2 you may have talked to FLWG aircraft for either the Mobile mission or the State mission.  I will agree that if FLWG aircraft were on the Mobile mission checking in with you they were instructed to communicate in Lat/Long.  So I would agree that from your perspective they were using the lat/long system. 

While the State mission was required to use USNG.  This was to be transmitted on the 800Mz system.  The aircrews that were on this mission were also told to communicate with you as a precaution, for the act of deconfliction of aircraft.  Again, you and Mobile and USCG were talking with lat/long so the aircrews were instructed to talk in lat/longto you. 

While SARJunkie point out "When you spend 30 min with the crew, give them a 'cheat sheet' on the radio and them have them demo it to you, you would think that they would understand.  approx 40% of the crews just couldn't handle it!

Its not an issue of propagation, or RF, or the system not working.  its 100% operator error."

I will also agree with his asessment. 

As with SARJunkie's asessment that all State agencies have been mandated to use the USNG, I am not sure that is the case.  What I can say with certainty is that any Agency that works with DEM as a primary or secondary agency MUST use USNG.

[Eclipse]

Pine neddles down here on the coast run an easy 14" in length

You obviously have played knifey-pine needle before...

[starshippe]

. . i have been in es for a few decades, and until this thread, had not heard of usng. i do not think the gps in our aircraft allows us to select usng as a coordinate system. i searched through the 536 pages of the g1000 manual, and did not find a reference to it.
. . when anyone says, we are all going to the usng coordinate system, are they also speaking of our cap aircraft? do we have any cap aircraft whose gps allows the selection of usng as a coordinate system?

thanks,
bill

[Thom]

. . i have been in es for a few decades, and until this thread, had not heard of usng. i do not think the gps in our aircraft allows us to select usng as a coordinate system. i searched through the 536 pages of the g1000 manual, and did not find a reference to it.
. . when anyone says, we are all going to the usng coordinate system, are they also speaking of our cap aircraft? do we have any cap aircraft whose gps allows the selection of usng as a coordinate system?

thanks,
bill

Bill, don't panic! No one is planning to change the way we do business in terms of navigation and flying, that will remain Lat/Long for the foreseeable future.

What is coming (sooner or later...) is that under the Federal system of SAR, particularly with the National SAR Committee, they have standardized on a number of different systems to be used, depending on whether you are Land SAR, Airborne SAR, Maritime SAR, etc.

As part of this effort, they have standardized on USNG as the primary system to be used by Land SAR responders. And, Lat/Long is the standard primary system for Airborne SAR (whew!).

Unfortunately, they also decided that it was the responsibility of the Airborne folks to translate their Lat/Long info into USNG when interoperating with Land SAR folks.

So, eventually, at least some of our Mission Base staff will need to understand USNG and Lat/Long so they can translate and relay to the Land SAR organizations. It would probably be a good idea to eventually train the aircrews in how to do this so that every message doesn't need to bounce through Mission Base when talking a Land SAR group into a target.

The Big Questions: How soon will Land SAR organizations adopt USNG, how uniformly will they adopt it across multiple organizations, and how soon do we need to be ready to interoperate with folks using it? I'm not taking any bets, the odds are still swinging wildly from month to month, and varies from one organization to another.

Here's a pic of the National SAR Committee's Matrix of Coordinate Systems, it lays it out pretty well.
And, here's a link to a short, but useful document: http://lawgcap.org/lawg-content/ladocs/SAR-Coordinate-Systems.pdf

Bonus: The National SAR Committee also picked Degrees with Decimal Minutes as the standard format for Lat/Long between organizations when Lat/Long is used, so hopefully, eventually, we can get most folks switched over to that from DMS.





Thom

[SarDragon]

A review of the GX55 manual reveals no provision for USNG.

[SARJunkie]

Florida is pushing VERY hard to to make USNG happen! right now most agaencies have transitioned.

[Eclipse]

Florida pushes a lot of things...

[Spaceman3750]

Here's a crazy idea... Learn both and use whichever one the lead agency tells you to use. It's not hard.

Now back to the regularly scheduled urination olympics.

[davidsinn]

I just found an online conversion tool from lat/lon to USNG

Latitude          Longitude        Datum            USNG
 
N38 52'22.08"    W077 02'06.86"    NAD 83 -> 18SUJ2344204629(NAD 83)

That's the output. In what way is that simpler? They claim the lat/lon to be the coordinates of the Washington monument but it is 3000m south east of there in the middle of the Potomac.

I ran that through google and it choked on it. Lat/lon is half a millenia old. What's wrong with it? It works. It's universal.

[SarDragon]

I just found an online conversion tool from lat/lon to USNG

Latitude          Longitude        Datum            USNG
 
N38 52'22.08"    W077 02'06.86"    NAD 83 -> 18SUJ2344204629(NAD 83)

That's the output. In what way is that simpler? They claim the lat/lon to be the coordinates of the Washington monument but it is 3000m south east of there in the middle of the Potomac.

I ran that through google and it choked on it. Lat/lon is half a millenia old. What's wrong with it? It works. It's universal.

I played with that converter the other night, anbd again a few minutes ago. I found a couple of things.

It appears that the datum for GE is NAD 27, and not NAD 83. I entered the converted NAD 27 lat/long into GE, and the error was much smaller - only about 700 feet.

I entered the USNG coordinates into GE, and it nailed the monument right on the dot.

I took a close look at a USNG tutorial online, and understood it quickly and easily. It was a good new trick for this olde dog.

YMMV.

[davidsinn]

I just found an online conversion tool from lat/lon to USNG

Latitude          Longitude        Datum            USNG
 
N38 52'22.08"    W077 02'06.86"    NAD 83 -> 18SUJ2344204629(NAD 83)

That's the output. In what way is that simpler? They claim the lat/lon to be the coordinates of the Washington monument but it is 3000m south east of there in the middle of the Potomac.

I ran that through google and it choked on it. Lat/lon is half a millenia old. What's wrong with it? It works. It's universal.

I played with that converter the other night, anbd again a few minutes ago. I found a couple of things.

It appears that the datum for GE is NAD 27, and not NAD 83. I entered the converted NAD 27 lat/long into GE, and the error was much smaller - only about 700 feet.

I entered the USNG coordinates into GE, and it nailed the monument right on the dot.

I took a close look at a USNG tutorial online, and understood it quickly and easily. It was a good new trick for this olde dog.

YMMV.

I put them into google maps because that doesn't require a download and is loaded on most smartphones by default.

[SarDragon]

Google maps and Google Earth are essentially equivalent behind the curtain.

[sardak]

N38 52'22.08"    W077 02'06.86"    NAD 83 -> 18SUJ2344204629(NAD 83)

That's the output. In what way is that simpler? They claim the lat/lon to be the coordinates of the Washington monument but it is 3000m south east of there in the middle of the Potomac.

The point is in the Potomac, but not 3000 meters. If you measure the distance between the point and the Washington Monument, it's about 1850 meters in a north/south line.
One nautical mile = 1852 meters = 1 minute of latitude.  If you change  38° 52' 22.08"  to  38° 53' 22.08" guess what? You get a point at the Washington Monument. The USNG coordinates change correctly, also.

It appears that the datum for GE is NAD 27, and not NAD 83.

From the Google Earth Users Manual (http://earth.google.com/support/bin/static.py?page=guide.cs&guide=22373&topic=23750&answer=148110)
Google Earth uses Simple Cylindrical projection with a WGS84 datum for its imagery base.

As with projections, there is more than one mathematical interpretation of the earth's shape. Google Earth uses WGS84 datum.
http://earth.google.com/support/bin/static.py?page=guide.cs&guide=22373&topic=23750&answer=148112

Google Earth and Maps are global products and WGS84 makes sense. About the only place you'll find anything in NAD27 are USGS topos. However, USGS is redoing them all in NAD83 (the federal civilian standard map datum) but its going to be a few more years until completion. The last ones they'll do are the "single edition" topos which are those which cover National Forests and are maintained by the US Forest Service. The old NAD27 ones will continue in use by those who have them - many, many of them.

I entered the converted NAD 27 lat/long into GE, and the error was much smaller - only about 700 feet.

That's because in the DC area the difference between UTM NAD27 and UTM NAD83/WGS84 is about 30 meters east/west and 220 meters north/south, for a composite of 222 meters = 728 feet.
I discussed that shift magnitude in my earlier post in this thread. What I didn't mention, but since we're on the topic, the lat/lon shift between NAD27 and NAD83/WGS84 in this area is only 8 meters south and 26 meters west. Where I live the lat/lon shift is 1 meter n/s and 50 meters e/w. You can almost ignore that.

Google maps and Google Earth are essentially equivalent behind the curtain.

Correct, both use WGS84 and a "pseudo-Mercator" projection, though the actual projections are somewhat different between them. One of the big differences though is that Google Earth, but not Google Maps, will accept input in coordinates other than lat/lon. One can copy and paste the USNG position being discussed  18SUJ2344204629  directly into GE (in version 6 anyway, I don't have anything running an older version) and have it plot out in the Potomac. Interestingly though, the coordinate options in GE list UTM but not USNG/MGRS.

For a converter between just about any datum and coordinate system, I recommend GEOTRANS from the National Geospatial Intelligence Agency (NGA) at http://earth-info.nga.mil/GandG/geotrans/
GEOTRANS runs in Microsoft Windows, LINUX and UNIX environments. Apple folks need to talk to the Government.

Mike

[SarDragon]

I think their DMS.S figure is wrong. Everywhere I measure the monument, it comes out at N38 52 22.08 and W 77 02 06.72.

Their NGS figure is right on.

YMMV.

[SARJunkie]

Tool Florida Emergency Mgt uses to convert / display:

http://floridadisaster.org/gis/kml/viewer.htm

[starshippe]

. . gpx files, which appear to be the standard for gps information interchange,
require the lat and lon to be in decimal degrees. there is currently no option
for any other format.
. . seems that rather than requiring everyone to speak a certain language,
it may work better for each group to speak their native language, and possess
an interpreter.

bill

[SarDragon]

There are several downloadable programs that will convert among the different unit systems.