1490T - 2012.4 Maps, Which JCV Files?

Well, that's odd.

First off (assuming you already have a backup made of your whole nuvi to a computer, DVD-R, etc.), the .sum file is an error-checking file created at some point. It may safely be deleted.

From a quick Googling, it looks like the 3153050a is the default jcv file intended for your nuvi to go with the 2012.40 map update and the 3178000a file was the jcv file supplied by Garmin for your ancient 2012.10 map update (and which, I expect, should have been removed during past map updates--hence, my confusion). [Hmm, is there any chance your nuvi has bits of two maps? Go to Tools/Settings/Map/MapInfo and see if your nuvi still thinks it has 2012.10 and 2012.40 installed. Hopefully, only 2012.40 appears on the list.]

Since both of these files are "tiny" <50MB files, the big >750MB file available for maps will offer you many more JVs and offer them in better quality. Just be sure to use the manually-downloaded jcv file intended for the map update version you have.

I suggest moving or renaming both of your 40-50MB jcv files so that the jcv file manually placed on your SD card will be used.

Report back if you have any problems--or success!

PS--Given that the nuvi 1490 has limited storage built into the device, rather than renaming and keeping old jcv files on the nuvi, I'll suggest removing them (making sure that you have a backup on a computer, hard drive, or DVD-R, etc.)

In fact, I'll also suggest removing all unneeded voices, help and text files, etc. from your nuvi to make space for future map updates without having to jump through extra hoops. If anyone here needs all of North America (at least the 50 states and Canada), it may be you!

I took your advice and added .old to each of the files in the Garmin's JCV directory and went out for a drive ... Works! Full screen junction views where I never had them before, very cool! I did notice a very slight delay in painting the screen, might swap in a class 10 MicroSD card for the class 4 in there now.

I did erase all the extraneous text and voice files, still gave me no where enough room for the big JCV file. Plenty of room however for the POI file, be nice to skip that install screen from keeping it on the card every time I turn it on.

Thanks for the quick and useful reply!

I'm looking to add an SD card to my 1490 to put the large JCV file on.

Anyone else have experience with class 4 or class 10 cards? I can get an 8GB class 4 card for less than $5 shipped - not sure if it will be fast enough though.

You shouldn't have any problem with a class 4 SD card. There is a school of thought that the class only makes a difference on "write" speed and the Nuvi only ever "Reads" from the card. I don't know if that's exactly true or not but I've used a class 4 card on most of my Nuvi's without any issues.

When I went to 2012.40 I downloaded what I thought was the correct LARGE junction view file - D3060050A.JCV. Can anyone confirm that that is the correct LARGE .JCV file for 2012.40?
That question begs two more: If not, will it still work with 2012.40? And, secondly, it not, where can I get the correct .JCV file? I have a Nuvi 1450, if that matters. Thanks.

That is the correct JCV file for 2012.40. Size is 775,260 KB (793,866,066 bytes)

I think that should be about 775 Mb for the largest JCV file !

edit : sorry - misread the post - my mistake

I believe that choosing a jcv file for a previous City Navigator NA NT map version will result in no JV display. And choosing a jcv file meant for other nuvi models but for the correct map update version will result in JV displays, but possibly distorted or of a lesser quality or fewer JVs.

Thanks for the confirmation. Two more questions: Before I installed the micro-SD card, the small .JCV file was in a hidden folder named (of all things) JCV. I created a JCV file on the SD card and copied the LARGE junction view to it and renamed the old .JCV and .sum files as .oldJCV and oldsum. The new .JCV folder on the SD card is not hidden. That won't cause problems, will it? And the fact that I renamed the original .sum file to .oldsum shouldn't cause problems, right? There is now no .sum file in any JCV folder.

the .SUM files are file checksums from running the diagnostics. You can just delete any .SUM files you find on your nuvi. There is really no reason to keep them after the diagnostics have run.

If you want the .JCV file on your SD card, it should go in a folder named \Garmin\JCV. The folder does not have to be (and should not be) hidden.

From my understanding the larger sized JV files are for the Garmin units that support the photo realistic Junction views and would have no effect other than taking up more room on the units that do not support photo realistic views. The largest 77x,xxx sized file is for the units that display a full screen photo realistic and the ones that do split screen like mine are about half that size.

My 3790 LMT has just been updated to 2012.40 maps and the JV file that was installed with the update was just over 400,000k. It displays a photo realistic split screen with the map on the left and the Junction View on the right.

Example link:
http://home.comcast.net/~rjrsw2005/pwpimages/Garmin%203790%2...

Okay, three more questions:
1. Can my Nuvi 1450 take advantage of the larger .JCV file?
2. There is now a folder named "Garmin" both in the 1450 itself and also on the SD card. The LARGE .JCV file is on the SD card in the F:/Garmin/JCV folder. I would assume that that .JCV file will be found on the SD card even though there's a "Garmin" folder already in the unit?
3. This afternoon I renamed the smaller .JCV file as .oldJCV in the unit. For the life of me, I can't find it tonight. It seems to have disappeared. I'm not kidding - it's gone. And so is the .oldsum file. What happened to them?

Answers
1. Yes it can use the big JCV file, on the SD card though.
2. The folder on the SD card is fine. On the GPS the JCV file will be found under ".System/JCV" folder, not "Garmin/JCV" as it should be on the SD card.
3. Make sure Windows Explorer or whatever program your usingis not set to hide system folders or file extensions. Also, since they are renamed now, search from the GPS root directory for "D*.old.*" and you should find them.

The SD card does not use the same folder structure as the Nuvi 1450 for the JCV or POI foldes. Hope this helps.

According to the Garmin site “Photoreal” is not supported by the 1450 so the larger JV files would not have any advantage on your unit and only take up more space. It may even slow down access time to the views.

The Garmin site says that “Photoreal” is only available on the 24XX, 25XX and 3XXX series only.

Quote from site:
"We are excited to launch Garmin’s own photoReal junction views across selected models on our new affordable nüvi 2000 series."

Rats! I was hoping for something really dramatic from the larger .JCV file. On the other hand, I've been impressed with the smaller file all along. Now all I have to do is find the one I renamed .oldJCV so I can rename it back. Still haven't quite figured where it went. Thanks, everybody.

I wonder if maybe Garmin doesn't supply photoreal to units other than the 24xx 25xx and 3xxx models with maps and map updates by default but that if manually downloaded and installed, the photoreal files would still work.

Those of us with "ancient" 8x5 models get a small default jcv file (not photoreal and maybe missing some junctions) but that the large 750+ MB JCV all-JV photoreal file works superbly if manually downloaded and installed.

The way to test this yourself, plunder, is to install the large photoreal file and see what the results are. Go for it and report back with your results! For what it's worth, I predict it will work on your 1450 as well. Once you've seen the max-JV photoreal JCV results on a nuvi that uses full-screen JV, you'll never want to go back to non-photoreal. We just need to hope that Garmin continues to offer the large file for manual download with each map update.

This is NOT really correct. The default JV file for the 1450 is only about 45MB in size while the large file is over 700MB in size. So although the 1450 may not support photoreal views (can't confirm one way or the other) it will allow the 1450 to display hundreds, if not thousands of additional views.

In addition it wouldn't make any difference to the performance of the unit in any appreciable way.

The larger file will give you more junction views. I have the larger file loaded on my 1490 and the only difference between the 1450 is the 1490 has bluetooth. The reason Garmin issued the smaller file was because of the lack of internal memory in the 14xx units. With the addition of a micro SD card, the larger JV file can be used.

I also have a 885 and have found that the full screen junction view is up on the screen for such a short time it is pretty much useless. By the time I realized it was there it was gone in a flash and really wasn't worth anything.

With the 3790 splitscreen with the map, lane assist and junction view staying up for 3/4 mile or so before the turn or junction it gives me the chance to actually see what info is being displayed. For the first time I actually see some value in having JV.

You will probably notice a very dramatic difference using the larger file. The views may not be photoreal but there will be hundreds, and probably thousands, of more views.

I don't know if there is a different level of photo realism on the newer units when compared to the views you get in the large JCV file on the older units. But I can tell you that the original junction views that came out on the 7x5 and 8x5 series back in 2008 were very "cartoonish". The large JCV file you get today has much more realism on the views, showing surrounding buildings, overpass structures, light poles, more realistic vegetation, sign placement, etc. Garmin improved the realism of the junction views several map versions ago. I don't remember the exact version, but it has been relatively recent.

I'll try it and report back. Unfortunately, there aren't many complex interstate junctions around here so it may be a while.
By the way, my 1450 has always displayed a full screen junction view, even with the smaller file. If, in fact, the large file behaves differently (ie, better), what do you speculate would happen? More junction views? Clearer junction views? What?

The thing that would show what the difference is between the small file and the large file would be for you to take a screenshot of each one using the unit's screenshot function at the same junction.

Then post both here so that everyone can see what if anything is different in what is displayed.

Are you familiar with TOOLS>SETTINGS>SYSTEM>GPS Simulator? When the simulator is on, you can set your location near an interchange then Navigate to a location across town.

The beauty of using the large jcv file on interstates when running a "GoTo" route is that even a simple exit from an Interstate should offer a great JV. But to really test it out, running the GPS in Simulator mode and planning a route with some more complex junctions would be more fun to view.

A true test would be to run some simulations with your current small jcv file to see if JVs are offered. If none are offered with the small jcv but they're there with the large jcv file, then we'd know that in additional to more realism, there'd also be more junctions offering JVs.

PS--remember that if you will soon be updating your City Navigator to 2013.10, you'll need a different large jcv file than the one now available.

Yes the 1450 has always displayed junction views, but as I've said in 2 posts above, you will see hundreds, and possibly thousands, additional views when compared to the very small Junction View file you now have on the 1450 (40+MB compared to 700+MB). Of course you'll have to drive or simulate a route with one and then the other file installed to compare and see the differences.

Actually there is no need to drive the route or use simulation mode to preview the Junction Views along a route. Just select a route or set a destination and press GO. Press on the green next turn bar at the top of the navigation screen. This will give you a list of turns along your route. Press the first turn. If a junction view is available for this turn, the "Lane Assist" button will be highlighted. Press that to see the junction view for that intersection. Press the down arrow to go through all the turns.

Why Garmin calls it "Lane assist" instead of "Junction View" in this context is beyond me.

t923347 Is there anything posted anywhere on the web that actually tells the difference in the number of junction views available for a particular map version for the different sized JV data files supplied by Garmin? I have never seen anything that tells how many are actually available in any of the files.

I was wondering where you got your figures of hundreds and possibly thousands of additional views difference between the different size files for the same map release?

Wow, another reminder that I learn so much here at The Factory. This is so much better than a test drive or a simulation at real-time speeds. Thanks a heap, alandb!

I forgot about that. I used that method in KC.

I don't know of any place where the actual number is but I have been told by Canada's largest Garmin distributor that there were well over 1000 views added to the Junction View file, for just Canada, a few map updates ago. Like alanb, I can't recall what update that was.

Personally I have traveled many thousands of miles in the last few years in the US as we have a home in Arizona as well as Canada. I can tell you from personal experience that you will be hard pressed to find an Interstate exit that doesn't have a junction view attached to it. That alone would add up to thousands of views.

In addition, it only makes sense that when your talking about a 40MB file compared to a 700MB file, your talking about one heck of pile of small picture files.

I've had the large JCV on the 1450's SD card shortly after updating the map as well as the 765Ts and the Zumo 665. There have been no problems at all on any of the units. I use the 1450 daily for work traveling all over Western PA, Upstate NY, Ohio and West Virginia. It has more realistic views and there are plenty of them.

Go for it!
As always, just do your backup first.

Awesome! I can't wait for my 8 GB card to get here so I can try the large file out!!

Yes the 1450 has always displayed junction views..., but you will see hundreds, and possibly thousands, additional views when compared to the very small Junction View file you now have on the 1450 (40+MB compared to 700+MB). Of course you'll have to drive or simulate a route with one and then the other file installed to compare and see the differences.

That's great to hear. Thanks for the report. The news of some non-interstate JVs is a pleasant surprise to me based on what I see in AZ.

Loop 101, Loop 202 & SR 51 are all covered with JVs in Phoenix area and not just I-10 & I-17. Almost every exit ramp, except a few that were under construction until recently, are in the big file.

You can add SR60 to that list as well but I think CraigW is referring to the lack of views on other than the major interstates and State Routes (controlled access highways) around the Phoenix, Tucson, and Flagstaff area.

Always used the larger JCV file on the SD card as well as the full NA maps and everything works fine. JCV views pop up just like you would expect htem to.

You would think Garmin would provide support for this on their support site and we wouldn't have to
use this great place to fill hte support void.