Welcome to GPSFileDepot!

Main Menu

Breaking maps into components

Started by jbensman, January 19, 2011, 11:13:03 AM

Previous topic - Next topic


One of the drawbacks of the topo maps on this site is they do not route and City Navigator data tends to be more accurate than the TIGER data.  That's why I have gone the transparent overlay route.  But it has its disadvantages.  The biggest is you can only see one map at a time in MapSource and BaseCamp.  I've been thinking about this and have some suggestions on how the best of both worlds might be obtained.   

One big problem with the transparent topo maps I have made is the water polygons cover up roads and many other things.  I've dealt with this by making a typ file to make major river and major lake transparent.  But that has problems too.  After I tried Matt Bell's CN Night mode map, it appeared he figured out how to get City Navigator's lines (roads) and POIs to draw on top of a polygon-what I had never been able to figure out. He told me the secret. 

First you have to match CN's zoom levels 23 bits 1 MS Zoom; 21 2; 19 3 ; 18 4.  You set the map to NOT transparent.  In mapsettoolkit you set draw priority to 30.  The result is CN's vectors and POIs draw on top of the polygons in the map.

That worked great except it caused big problems for the topo lines.  The zoom levels made a mess because they drew at too high of levels.  So I ended up having to split the maps.  I used his solution for the hydrology polygons and kept the contours lines and hydrology lines the way they were.  So I have two separate maps for the same area.  I have both the topo and hydro imgs in the same directory and they both show up in MapSource.  Even though the contour imgs are set to transparent and the hydo polygons are set to not transparent, it works perfectly on the GPS.  CN's vectors draw on top of the hydro polygons and the topo/hydrology lines draw on top of everything. 

So my suggestion would be instead of putting everything in the quad on one img, break it down.  Put topo lines and hydro vectors in one img, hydro polygons in another, and everything else in a different img.  The result would be in MapSource you could see everything.  You could chose what you send to your GPS.  If you had CN, you could select just the topo lines and hydrology.  Or you could select everything and send it to your GPS. 

Would not this also make it easier to update the maps when there is new TIGER data?  Instead of having to compile imgs for everything, you would just have to make new imgs for the road data.

Then there is trails.  My Trails now covers 37 states and I have spent countless hours working to obtain the best trail data available.  But a big complaint is in MapSource all you see is the trails.  One complaint about many of the topo maps on this site is they don't have trail data.  The solution: include the state trail img from My Trails in the directory with the other state imgs.  Then in MapSource the trails will appear in the map.  I am constantly updating My Trails with new and better data.  Whenever My Trails is updated for the state, all one would have to do is replace the img file in the state map directory with the new img.  Or maybe there is a way to modify the install script to check for this and replace the img in the state directory automatically.

I can think of a couple of issues.  First if they load the img from My Trails and from the state map set, it could cause conflicts.  Another issue is after the trail img file is updated, it will always display in MapSource, but if the trails img is selected and sent to the GPS from the state map, they may get the "your mapset is 27 megs and you only have 1158 megs on your GPS" error.  I think both of these problems could be avoided by telling them to load the trails onto their GPS from the My Trails mapset and not send the trails to the GPS from the state mapset.  I am not sure if you can have the same name for an img in two different mapsets in MapSource.  I do not think it causes a problem in MapSource, but I know it does on the GPS.  I've mistakenly given the same names to img files in different mapsets.  It worked fine in MapSource, but when you sent it to the GPS, only one displayed. 

Maybe there are some problems I am not thinking of.  But I thought I would throw this out as a possibility.  I am willing to allow My Trails be used like this as long as the non commercial use limitation is maintained.  Lots of the data I have in My Trails was provided to me on the condition it only be used for non commercial use. 


Does not the CA topo do this or something similiar?  It has the planimetric data (non contours) in one set of files and the contours in another.  Both show in MapSource, but there have been numerous posts from those who unknowlingly only selected quads/tiles/segments from one to be sent to their GPSr.  With three mapsets in one I would expect even more users would not comprehend how to do it properly, especially if you did not want all the data.  Have you tried this (and what seams crystal clear to you the creator might not be to others - we get many questons on simply installing and uploading a single mapset)?  

Also remember the 2025/4000 segment limits.  I would expect with 2 or 3 layers of data each would count.  The contour + hydro data could be many times larger than the transportation - in metro areas it could be smaller.  

Updating only the TIGER transportation data would NOT produce a current/best available map.  The TIGER data is updated/released on a 'yearly' basis.  NHD is a work in progress - active areas may have changes on a daily basis.  USGS releases new/updated NED on a two month basis.  GNIS is also a work in progress with packaged updates every month or two.  

The State topos I created used 'standard' sized quads named by coordinates.  If the same quad was selected from two mapsets, the quad appeared twice in the listing window in MapSource.
However, only one copy of such quads were sent to the GPSr (and the gmapsupp.img file size also indicated this).  On the GPSr, if one of the States with such a quad was hide/disable, such quads many or may not disapear depending on which State MapSource had included the quad(s) in when it built the gmapsupp.img file.  I never tried to determine if there was any pattern to which States was used.

There might also be confusion with self-installers for a clean/full install versus replacing existing file.  It appears MapSource gets file size info from information in the .tdb and/or overview .img file; a large difference in file sizes might cause a problem.

You are intending this to work with CN; have you given any consideration to how this might work (or not work) to add contours to Ibycus, my planimetric mapsets, and or OSM planimetric maps? 


I agree confusion could be a serious issue.  But clear directions on the map page could help.  The map page could also contain links to a mapsource All Maps.mps, planimetric.mps, and  Topo/Hydro.mps which would have the proper maps selected.  Then all they would have to do is open the appropriate mps file in mapssource and select send.

I am betting the segment limit would not be that big of a problem.  It would be close to you putting your planimetric and contours in the same directly and providing them as one mapset instead of two different mapsets.  You have the same number of segments.  But the hydrology adds additional maps which would add segments.  I will be able to give a better answer in a couple of days, but I am betting all the hydro maps can be combined into 2 or 3 segments.  I am working on converting My Topos - right now the hydro maps are about 40 megs and the contour ones are about 1.2 gigs.  My plan is once I get everything converted, to combing the hydro imgs into as few imgs as possible. 

Ibycus is not routable and the new maps would have better data.  So I would say Ibycus would be obsolete and no need to worry about it.  I think your planimetric maps are far superior to Ibycyus.  If your planimetric maps are updated with new tiger data, hydro polygons separated into another layer, and then combined with your topo lines, would there be a need for your planimetirc and topo lines mapsets?  I think it would be great if the best data was all combined into the same mapset with the ability to chose what layers to load on your GPS.  The OSM, I do not know.  It depends on if OSM uses the same zoom levels as CN.  Does anyone know?  If it does, it should work with it too. 

"It appears MapSource gets file size info from information in the .tdb and/or overview .img file; a large difference in file sizes might cause a problem." That does not cause problems in mapsource.  The only time it would be an issue is if the trail img got out of wack and you tried to send it to your GPS from mapssource (you would get the your maps set is 20 megs and you only have 1 gig free" error message.  It takes quite a bit for it to get messed up.  This is why they would need to be told to send the trails to their GPS from My Trails mapset, not the state mapset.  While this might be confusing, it would prevent any problems. 


   Ibycus has been obsolet since Dec., 2008.  He was going to update it and add contours, but seams to have lost interest when he lost the ability to serve files on his website (also by then there was a 24k topo mapset available for most States and the regional topos).  That release completed the realignment for the remaining 1/3 counties and also was the first where Census released the full extent (detail) of the TIGER files. 

   OZ is reluctent to remove mapsets and especially the very popular ones.  Note that his AZ topo is the only one of the four most downloaded which has been updated and he is the only map author of the four who is still active (two never were on this site).

   About 1 1/2 years ago I suggest having a planimetric and a contour mapset series; however, he felt it would be too much for most users to have to combine them and prefered the duplication of having a topo and a contour line mapset.   Why anyone is still interested in Ibycus - guess it is because it is general/basic enough that the entire country is one file under 1Gbyte in size.

    The OSM data I downloaded last summer was using 24, 22, 20 bit levels.  Given the building, etc. detail the Europeans have, that is more appropriate than Garmin's 23, 21, 19, 18.

    See how it works.  As the only thing constant in life is change, OZ may have changed his opinion as so many of the mapsets are now 2 and 3 years old.


Maybe the thing to do with the older obslete maps is too have an archive.  I think this would make it easier for someone to pick the best map.

I've got My Topos all split up and CO Transparent Topo 3/4 of the way done (and will be uploading Win/Mac versions in the next day or so).  Everything seems to be working perfect.  The hydro polygons have not caused a problem with additional segments.  I was able to combine quads and have about 2 imgs per state with the hydrology polygons.  Since there are so few hydrology imgs there would be an easy solution for the OSM maps.  It would be no big deal to change the zoom levels to match OSM, compile them, and then create a single img file that could be put on the GPS and upload the img here. 

Then you could have a single mapset that had all the street data in a set of imgs. countour/hydrology lines in a img set, a My Trails img, and hydro polygons talyoered to City Navigator.  You could either send everything to your GPS, if you had City Navigator - send the contours, trails and hydrology, if you had OSM, send the topo lines and trails and load the compiled img with the hydrology directly on the GPS.