Mile Markers to Coordinates?

If you have GPS why is this of any use?

This was helpful, How?

What's interesting to me is that the City Navigator North America NT map has interstate highway MMs embedded in the map itself. They can be seen on a computer with Mapsource when zoomed in to 0.3 mi or higher zooms. They don't seem to appear in Basecamp on a computer or in a nuvi display.

for the OP to do what he wanted?

I can't imagine a way to easily turn the MMs into waypoints to be transferred to a nuvi as Favorites or turned into a Custom POI file other than by manually creating a waypoint for each MM and exporting the file. I suppose it's do-able for stretches of highways frequently travelled for which you want the values, but coming up with a nationwide, statewide or even county-wide area would be an immense job.

I can see where it could be useful for emergency/LE folks in going to or identifying accident or crime scenes. I suppose the average person could also use it to describe an accident location to 911 or some such thing.

Further info: In Mapsource, when hovering a mouse over the black dot interstate highway MM, you get the MM value (e.g., 201, not MM201). I also see MMs as black dots on state highways and some other streets but a mouse hover over these non-interstate MMs results in Unknown rather than a number.

While it is possible to see MM's in Mapsource when zoomed in to .2 miles or higher as CraigW pointed out, it would require a lot of work to manually create waypoints for all of them.

Perhaps one of our Garmin gurus could come up with a way to extract the MM coordinates in bulk directly from the CNNA map code.

Let me add to my query. How many times have you been traveling down an interstate highway and paid attention to EVERY mile marker you pass? If your vehicle became disabled or you had an accident, would you know what mile marker you just passed or are approaching? I might get within 10 miles or so and that probably wouldn't be very helpful. When calling for help (law enforcement or tow) I could identify precisely where I am at. Coordinates down to at least a half mile would seem to be idea but I'd be happy with mile markers point to point.

It seemed to me this would be a perfect POI project and use for a gps unit. I'm not sure how images could be incorporated into such a file as each one would need to be unique. Audio files would drive you nuts after a while and they too would have to be unique. I was just wondering how to convert mile markers in bulk.

I had another idea in mind when I asked this question too. In my state the highway patrol operates truck weigh scales. These officers are armed and it would make an idea place to exit in the event of road rage, etc. Their locations are only given as mile markers along the highway and I wanted to convert them into gps coordinates. It seems like every day you hear of someone in the news media that dies at the hand of such road violence.

Thanks again.

eKeith

Don't junction views have the exit numbers, which is the mile marker? Maybe something could be done with that.

I haven't checked this feature in great detail, but what happens if you press the "Where Am I?" button on your GPS? It may give you the answers you are looking for if you are on the highway. I just don't know enough about this to confirm.

I loaded "mile" markers for highways once in Europe. They were added to other POIs. Totally pointless and useless thing. Originally they were make to "beep" when approaching. After few minutes it was just annoying. Alarm after every kilometer. When you are traveling about 150 km/h (90 mph) you got beep or screen alarm more than twice every minute! Finally I get rid of sound file and left just icons. After a while I get rid of them, as there is no point to look for those markers.

Practically if you like to have a lot POIs loaded to GPS that's probably all they are good for. As useful as constant reminder "your car is moving forward". If you looking for something more useful look for "emergency phone" POIs. They are on some European highways and if you have problems and need help this is better solution.

It appears someone has created a tool for Interstate 95 that converts mileposts to lat/lon. I wonder if one exists for the entire Interstate system?

http://tinyurl.com/m5y7n9h

The Dezl 760 has a "next Mile Marker" function you can turn on and have each "next mile marker" displayed as you approach it. Seems to work on all highways that show ,mile markers.

Wil

You wouldn't be too far from a marker. Every Interstate highway I've seen also has smaller mile markers every one tenth of a mile, similar to the one in the link below which reads 36/.5 meaning 36 and one half miles.

http://www.castorandpolluxmusic.com/wintersolstice/pics/mile...

Although they should be, not all exit numbers represent the mileage. I know of a few limited access highways that have sequential numbers instead of the mileage number in my general area.

Aha, when I first learned of the MM data in City Navigator, I thought that some special devices or possibly future firmware updates for other devices would be able to utilize this data.

So we know now that the Dezl 760 has the feature. I wonder about the other truck/RV devices. It would be great if future firmware updates for nuvis allowed this option as well--or, as suggested by others above, if the MM data could be displayed as part of the Where Am I screen.

Using Mapsource I created a gpx file of the Overseas Highway from the Card Sound junction at mm126 to Key West at mm0. I went a step further and created a unique bmp and wav file for for each mm and saved as a MMTourGuide file.
We spend our vacation in the Keys, with our lodging at mm53. Many restaurants & attractions advertise in the brochures listing their address as MMxx. So this file works very well.

When it comes to locations in an emergency you can always obtain coordinates from your GPS. All, yes that's all 9-1-1 centers can accept GPS coordinates as a location. Even the one in South Carolina where the call taker once said "Bubba don't do Lat Lon." can take GPS coordinates and input them into their dispatch system for your location. They can then question you to be certain the landmarks on their system match what you see.

Here in Iowa - the posts with the little white, round reflectors on the top of them along interstates all have marker tags on them... give the highway patrol dispatcher the number off one of those, and they'll find you...

a_user:

I didn't know law enforcement could use GPS coordinates to find a caller! Makes sense...you might have just saved my (and other readers') bacon with that tidbit of info. Given where I live I would expect the same response as "Bubba in SC" when giving them GPS coordinates.

I doubt though that a local towing service would have such capability even though it would only require having a GPS unit and inputting the coordinates. I suppose one could ask if the operator had a GPS unit which would be a good rule of thumb.

I still believe the closest/next mile marker being displayed on a GPS unit could be very beneficial. I've thought about this much more since my original posting and it would be a mammoth POI project perhaps impossible to do. I don't see any responses yet on how to determine the longitudes and latitudes of mile markers. I have wondered too how accurate are the placements by state DOTs. I'm going to contact my DOT and just ask if they have the coordinates.

Creating 100s of subfiles (for mile marker x on every interstate highway) and icons seems daunting. (The length of Texas is about 790 miles and California is about 770 miles which would require at least 790 subfiles. I'm not sure custom POI files of that size can be handled by most GPS units.) This may be more appropriate for the manufacturers to incorporate into their mapping software.

Thanks for the many comments!

eKeith

kch50428:

Despite the interstate highway system being a national (standardized?) system, I don't think the mile markers are uniform for every state. I've traveled many states and noticed differences in mile marker signage. I have not carefully looked lately but in my state I think there is only whole number miler marker signs. I have noticed in some states half mile marker signs. I have noticed some odd-looking reflective posts at uniform distances but I never noted any numbers of them. When I lived up north, the mile marker signs were very different to accommodate the depth of snow in the winter. If anyone knows more, I'd welcome knowing.

eKeith

Thanks, I thought the exit number was the mile marker number. Didn't realize some were not.
Thanks again

That would be a major undertaking

All I know is the reflector posts between mile markers on Interstates in Iowa are tagged with numbers that I think are to the 1/10th of a mile... Have heard state patrol dispatchers on scanner talking to local dispatchers trying to locate someone on an interstate and the state dispatcher told the local dispatcher to have their caller get out of their car, and get the number off the reflector post... one would have to do that, as the numbers are on small plastic plaques affixed to the reflector post.

As to the dispatchers getting GPS info... It has been FCC rule for some time now that cell phones be capable of relaying gps data from the phone when 911 is dialed... And only more recently have 911 call receiving centers been required to be able to read the location data from incoming cell calls. That's all automatic... Even 'dumb phones' can send their location when calling 911... For smart phones, there are apps... various map apps that will give you a quick 'SOS' page with a direction and distance to a nearby intersection one could use to summon assistance... Or you can get exact coordinates you can with a tap or two send via email... Options abound...

The New Jersey Turnpike is an example:

http://www.maikoff.net/njt.html

I-95 in the State of Delaware is another:

http://www.aaroads.com/delaware/i-095_xl.htm

as well as I-495 in Delaware:

http://www.aaroads.com/delaware/i-495_xl.htm

I was on US Route 1 yesterday in Delaware County Pennsylvania, some of which is a limited access highway. Along the guide rail every tenth of a mile are markers indicating as much, Mile 40.6, 40.7, 40.8 etc.

Here's a short video of them, hard to see at highway speed, put the youtube setting on HD:

http://www.youtube.com/watch?v=TVKXHQ9b_V8

Stills from the video: (if you are using Norton anti-virus photobucket links may give a false alert)

http://i184.photobucket.com/albums/x101/soberbyker/406_zpsc0...

http://i184.photobucket.com/albums/x101/soberbyker/407_zpsfa...

http://i184.photobucket.com/albums/x101/soberbyker/408_zps49...

Driving along, knowing they were there, I could see several coming up at all times, be pretty easy to zero in on where you are if you had trouble, 1/10 of a mile isn't much and these signs are fairly easy to read.

Mile markers are uniform in every state as roads are numbered from south to north and west to east. But that doesn't mean the distance between markers is always a mile at the borders. As they are measured from the state line or the beginning of the road, it is very likely the road may be 438 7/16 mile from border to border in state A but the next mile marker you may see is milepost 0 just 7/16 mile past marker 438. Over the past 30 years the exit numbers on federal highways are all supposed to reflect the mileage so Exit 10 is near mile marker 10 but may actually be before the mile marker or after the next. It has to do with the direction the engineer was going when the exit number was issued. This normally happens when there a A and B exits as they will both carry the same number. I believe the last state finished converting all their exit numbers from sequential to mileage in 2007.

You can often find mileage markers in other places than the standard post type sign. A lot of the bridges and culverts also have their location described by mileage, the same with light poles and other signs put up by the state. With GIS systems tied together, a great many 9-1-1 centers can tie into the highway database and find a location based solely on the markings from roadside equipment. Think about it, the state highway department wants to know exactly where that $450,000 electronic roadside sign is located.

I'm the OP and live in Northeast Tennessee and drove I-26 S & N today and paid careful attention to mile marker signage. I initially noticed the mile markers were small green signs imprinted in white with "Mile xx" (Mile was in a much smaller text than the number) and they were located on the right of the highway only at one mile intervals! As I entered a city limit, the mile marker signage changed to larger blue signs that had the direction of travel indicated on top, interstate highway/symbol number underneath, whole number mile marker number underneath above and on the bottom the miles in tenths only in even numbers. The blue signs were very much larger than the small green ones. These signs were placed at every two-tenths miles on the left (in the median). When I left the city limit, the mile markers returned to the small green signage at every mile.

I do specifically recall seeing mile marker signage elsewhere marked at half-mile intervals.

So judging from the comments here in this thread, the states seem to be inconsistently displaying interstate highway mile markers. (You would think that would be more uniform but apparently it isn't.) I still maintain that the small green signs only a mile intervals and my tendency to not note every mile marker I pass that gps coordinates for mile markers (down to at least half mile) would be very beneficial.

I communicated today with someone I regard as a GPS expert and he operates a related and very popular GPS website. It's the most robust GPS website I know. He advised me that if MapSource (which I am not familiar with but have heard mentioned here) has mile marker data in it that the data could be extracted and converted into way points to create custom POIs. Does anyone know the file format of MapSource? Has anyone looked at the coding? There must be a key words/character strings for the mile markers in MapSource.

I hope there is continued discussion of this topic and some genuine interest in creating POIs in some manner might arise.

eKeith

One person in this thread mentioned mile marker coordinates could be found in Garmin's old MapSource. I'd like to explore that possibility. Correct me if I'm wrong but MapSource was available before the current mapping application, BaseCamp.

I did a little research and found that MapSource is essentially a PCX5 file and looks much like a common csv file. I've looked at several sample files but I did not have actual MapSource maps to look at mile markers to examine how they are arranged, etc. Does anyone know where I can obtain a copy of the last release of MapSource? There is likely "a numeric code "66" or "8195" (depends on version of MapSource used) specifically assigned to mile markers.

If anyone could send me an entry as it appears in MapSource map PCX5 file that may be sufficient for me to see what may be required to extract the data. The mile marker way points would obviously be buried among millions of other POIs so a script of some type (maybe even a mega spreadsheet) would have to be written to extract the information to a file. That file in itself would have quite a few POIs as they would at least equate the number of interstate highways miles there are.

I have someone in mind that may be willing to write the script. I really need the last copy of MapSource maps. I am willing to pay someone for their trouble. I have searched the usual places but to no avail.

If anyone has any experience with doing something like I am thinking, I would welcome hearing from you. If not publicly, private message me. I still believe there would be much value to having a mile maker POI file to always give me an idea of where I am along any major highway.

eKeith

I responded to a PM request from you recently. I did not receive acknowledgement or thanks for my work.

spokybob:

I appreciated you took the time to respond to my PM but your reply consisted of exactly seven lines (in my e-mail program)! The message began, "...I don't know an easy way to convert mile markers to a custom poi." Well, with all due respect, that is precisely what my PM to you was about! You essentially go on to say, "create a new MapSource file" and if I didn't know how to do so, I should check the forum FAQs...that's really helpful! Since I don't have the MapSource application maps to create a file, your "tutorial" honestly made little sense to me. I was hoping once I found a copy of MapSource maps that maybe it might be more beneficial. My public apologies for not simply acknowledging or extending thanks for "your work" otherwise.

eKeith

http://www8.garmin.com/support/download_details.jsp?id=209

Here's a link to the MapSource PROGRAM. If you already have BaseCamp installed, then this will install over top of it.

The MAPS come from the maps that you (the user) install during a map update. Note that they are City Navigator Maps not MapSource maps.

No one can give you their maps.

If you have not already done it.You will need to change your Nuvi 2597 GPS from MTP to Mass Storage mode to connect to Mapsource. See http://www.poi-factory.com/node/41416

This is great information. Does the Coordinate Format matter?

I set mine to decimal format, but not every GPS will format that way.

Apparently your email program did not download the screenshots I provided.