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real topo maps for garmin?

Started by TEXN, March 09, 2010, 06:08:20 PM

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I am going through the painstaking process of trying to convert my routes, locations, etc that I recently had on my Lowrance XOG so they will work on my new garmin nuvi 550. I believe that I got the "data" file converted alright from the .usr format to one that will work alright in mapsource.

The problem I am having is trying to convert the numerous topo maps which I bought from Lowrance's "mapcreate" to work in the garmin/mapsource. The topo maps from "mapcreate" are basically blown up images of actual topography paper maps, which I prefer since it has detailed writing on paths, etc. An example of what topo maps I am talking about is shown in the link below.

The current topo maps that I have already are labeled for example:


Are there any custom maps that have this type of topography that I can already download onto my garmin?

If not, how can I convert the .at5 file to something that will work in my garmin?

Thanks for the help guys.

I would appreciate any help you could offer. Please give me layman's terms. I am def a newbie at this. Thanks in advance guys.


That link doesn't work for me. But if you want "real" USGS topo maps (eg: scans of paper maps), you should probably sell your Nuvi and purchase either a Colorado, Oregon or Dakota GPS. These models can use Garmin's new "custom maps" format which no other models support. See:

A number of these maps are starting to appear here. Go to this link and "filter results" check the box that says "Garmin Custom (CO, OR, DA) to see some examples.


When I go to your link, I get: 'Sorry, the page you have requested cannot be found'.

Each GPSr manufacture uses their own propiatery format, so it is unlikey you would be able to convert the data files.  

The Garmin CO, OR & DK units can display georeferenced image files.  USGS has these available for the 250K, 100K and 24K topo maps.  Garmin's current 100 cell limit (1024x1024 pixels) is close to the limit (in some cases under) which it takes for one of these maps.

Not sure what you mean by 'it has detailed writing on paths, etc'.  Sounds like something Lowrance or you added, so would not be on the images from USGS.

The various State topo maps on this site use USGS gridded elevation data to create contours at or close to the contour interval used on the printed USGS 24K quads.  What area(s) are you looking for?


I am interested in Texas topos. I have downloaded the Texas topo available on here already. The type I am looking for should be shown below. Mapselect has downloads that allow to pick sections of a topo map to download and place on your gps device. Their description are as follows:

Unique, downloadable maps for Endura™ GPS handhelds and XOG™ with U.S. satellite and aerial imagery, enhanced USGS topographic data, and BLM mapping.

So you are saying I may not be able to place them on my Nuvi 550 because of the resolution limitations on it?


There are two basic categories of GPS maps:

1. Vector based. The map contains objects which are made from lines connecting sets of coordinates. There are 3 types of map objects - polylines (like roads or contour lines), polygons (like lakes or parks) and points (like towns and points of interest). To create this kind of map, someone needs to actually trace the desired features and create a list of coordinates to be connected by the GPS software. All of the "classic" Garmin maps are vector based, and most Garmin GPS'es (including yours) can only use this type of map. Most of the maps on this site are vector-based.

2. Raster based. The map is actually a picture which can either be scanned from a paper map or an aerial photo that has been adjusted to be geographically correct. The example you have shown is a raster based map created by scanning a USGS topo. The only Garmin units which can directly support this type of map are the Colorado, Oregon and Dakota series. Your Nuvi cannot use this type of map. The Lowrance Endura, Magellan Triton, and DeLorme PN series all support both raster and vector maps.

So you are pretty much out of luck if you want to use this kind of mapping unless you purchase a unit which supports it. Depending on what you buy, you may need to make the maps yourself as well (such as the "Garmin Custom Map" link that I posted above). The map data itself is readily available for free from a variety of sources, but it needs (1) to be converted to the correct proprietary format and (2) a GPS unit capable of using raster based maps.


As Boyd stated, your Nuvi will not support raster image maps.  The Garmin units that will only be able to display one or part of one image of a USGS quadrangle.  The vector mapsets available will not look like the printed USGS topo quads because USGS has only produced the required 11 theme files per quad for about 4% of the quads for the 48 States.  We get most of the data from other sources and hope for a good 'fit'.  Those 'maps' mentioned for the Endura are image products which your Nuvi is not capable of using.  In the Garmin line, you would need an CO, OR or DK; obtain the data from the original source agency (or commercial purchase); convert the image to kml/kmz format (perhaps resizing as necessary).  Might be better to stay with a Lowrance product since you already have the data.


Thanks for the explanation of Raster v. Vector.  I stumble onto knowledge everyday.