Any upper limit to IMG tile file size?

[Seldom]

I've got a map with three tiles, between 17.5 and 24 MB each.  These show fine in MapSource/Basecamp, but when I load them to my OR300, they don't appear on the activate/de-activate map screen.  Tiles are routable, with lots of not-routable features (hydrography, contours, and woods.)  Routable features are from OSM.IMG file converted to MP.

[maps4gps]

Largest file I remember making was around an 8Mb .img file of contour lines only for my State contour line mapsets.  I do not remember if I specificy tested this file; however there has not been an email nor post of any issues with that series of mapsets. 
Files that large would not be workable for me as full topo files are taking up to 2 hours for cgpsmapper to compile an .img in the 3-4Mb size range.

[Indrid Cold]

I've got a map with three tiles, between 17.5 and 24 MB each.

I make tile this large all the time and they work fine, so something else

[Seldom]

Just to be clear, the IMG files are between 17 and 24 MB.  The MP files are around 300 MB each.

[Indrid Cold]

Just to be clear, the IMG files are between 17 and 24 MB.  The MP files are around 300 MB each.

Yes, I caught that the first time. The only issue I've seen with the larger .img files is not fitting on units with limited memory or slower redraw but I've made and used .img files well over 24MB

[maps4gps]

Was clear to me also that these were .img file size.

How long does it take for files that size to be compiled? 
I had wanted to increase my average .img file size to between 3 and 4 Mb; however, with up to 2 hour compile times for a 60Mb .mp file, I backed off to 1 - 2 Mb .img file sizes.

[Seldom]

Compile time is about an hour per file using multicore cgpsmapper personal 100d, with "generalization plus intersection" and all address search options set.  I'm using Win7-64 with 8GB ram.  With the switches set to "generalization only" they go in 4 or 5 minutes.  I'd use "generalization only" all the time if I wasn't trying to search for intersections.

[Boyd]

The largest tiles I've created are about 12MB and they are fine. But these are not routable maps. From what I've seen, compile time is not directly correlated with file size. In fact, it really bewilders me. I have some 8 to 12MB tiles that will compile in a manner of minutes. There are others only 4 MB that can run all night. There doesn't seem to be any immediately obvious reason for the difference.

Again, these aren't routable maps, but highly detailed topo's.

[maps4gps]

Thanks for the info.

seldom_sn: I use free 100d on 32-bit Vista 3Gb RAM dual-core.  Three year old computer; however, in checking recently the CPU speeds are currently only about 50% faster.  For a topo type map, 50-60Mb .mp files compile to 2-3Mb .img files in 40-50 minutes; 10-30Mb .mp files compile to 1-2Mb .img files in 5 to 25 minutes.   When I did the Oregon topo last fall, I was trying for an average .img file size of 3-4 Mb - the compile times for the larger files ware close to 2 hours.


Boyd:  Lots of variation in compile times.  I have noted .mp files of adjacent areas which differ by less than 1 percent in file size can have compile times which differ by 4, 5 or even 6 times.  Some of the difference is related to the mix of feature types; size and complexity of polygons - a few small isolated lakes versus extensive areas of complex wetland ares with numerous 'islands', etc.; large metro area with 10s of thousands or 100,000+ two coordinate pair street segments versus mostly a small number of 'thru' contour lines with each line comprised of thoursands to 10's of thousands of coordinate pairs.  For the extent and complexity of the surface cover polygons on your New Jersey topo, I would expect you are giving cgpsmapper a good workout. 

On the other side of the coin:  I just finished compiling 192 files in about 30 hours and which was within 1/2 hour of the estimated time based on shape file size and mp file size.  Based on all the variables, I would have considered within 2 hours a good estimated, so this was more luck than the usual.  However, for previous blocks of 192+- files within the overall dataset it was not unusual to be within an hour for 10 to 16 hour estimates.  Conversly I have adjacent file where the second one was twice the size but only took 1/3 or 1/4 the time to compile.  Estimates for large numbers of files can be reasonably accurate; however any two files might differ by an order of magnitude. 

[jbensman]

Let me tell you my tricks-I am not sure if this will work with globalmapper, but it works with Gpsmapedit.  When I try to compile some larger maps (with My Topos) after a couple of hours I will get an error message and it aborts.  I think it has something to do with RAM.  You can watch the amount of RAM being used steadily increasing.  (Note even with a quad core, it is faster to compile one big map, then the next one than to compile them both at the same time-this is due to RAM usage.)

OK for the trick.  If I have a mapset that will not compile due to being too big, I will split it into two parts and compile them seperately.  GPSmapedit will open an img and let you save it as a mp file (which is much smaller than the original mp).  So after I compile the 2 imgs, I open them both in gpsmapedit and save them as a mp file, then I will compile a new img file-while it may take a couple of hours for the first imgs to compile, the combined img only takes a few minutes to compile.

As you know, I regularly update the hydrology in MY Topos.  The first time I create the img from the source data.  When I update the hydrology (add something missing), I do not use the original MP file.  I will open the img file, save it as a mp file, then edit this mp file and then compile a new img file.  If I used the original mp file, it can take an hour or more to compile.  When I do it this way, it only takes a few minutes to create the new img.

[Seldom]

Got it working now.  I'm pretty sure the problem was caused by an IMG name conflict.  I had been generating the IMG name from the SW corner of my tiles, and since I have been re-working the same area for a while, I must have had maps of the same name on my OR.  When I switched the name from 37001130 to 37011131 the maps worked and showed up on my OR.

On the way, I came across the "you need 51MB for the map, but you only have 2500MB on the card error" in MapSource.  The maps that showed that error didn't have an 0x4b polygon.  When I added that back in, the maps transferred to the OR just fine.

[maps4gps]

I too have just run into some strange operation on my OR300 of mapsets with the same file (same file name) in different mapsets.  What worked  OK in my 2008 State topo mapsets (as tested on my 76csx) will not work as well on the OR and I assume other newer models.

[jbensman]

I can also confirm maps with the same file name in different mapsets results in only one of the mapsets showing on my OR550T

[Seldom]

I can also confirm maps with the same file name in different mapsets results in only one of the mapsets showing on my OR550T

I wish I could get my OR to give me a list of IMG files that are on it.

[jbensman]

gpsmapedit will.  Open the compiled img files loaded on your gps in it and it will list them.  If you img set to open in it, all you have to do is double click on the img file and it will list all the img included.  Otherwise, just drag and drop it.