After I finally sprang for a GPS unit I was a little disappointed to fully realize that they wanted me to pay another $200 for the maps. There has to be a better way, I thought…
These notes are for my Garmin GPSmap 60CSx.
Here’s what I’ve done so far:
Get some maps
I found a nice map of all the Washington roads at MapCenter. The binary IMG file is directly Garmin GPS compatible. (There’s two roadmaps for Washington, one from 2005-09-19 and one from 2006-03-04.) Another good Washington source is (oddly enough) the Washington State Office of Financial Management. More map sources are listed below.
Create a Garmin .img map from a .shp shapefile
- Get a shape file and open it in GPSMapEdit.
- File -> Save Map As… (Save as type: Polish format (*.mp, *.txt))
- File -> Export -> Garmin IMG / cgpsmapper.exe (Save as type: Garmin MapSource map (*.img))
- Enter the path to cGPSmapper.exe
- Run (this may take awhile.. like 1 hour)
- On my first try I got “Error E024: Top layer detail level too high to cover entire map – decrease detail level of the less detail layer (use higher Level#).” Let’s try adding another layer..
- File -> Mp Properties -> Levels -> (highlight Level1) -> Insert Before
(highlight Level1) -> Change… -> Bits -> 18 -> MapSource zoom range -> 3 (these are complete guesses)
- That didn’t work.. let’s try bits 20 and range 2… ok!
- Verified GPSr viewable after manual copy+rename to microSD card.
More info on E024
From the documentation (get it fresh here):
E024 Top layer detail level too high to cover entire map – decrease detail level of the less detail layer (use higher Level#).
This error needs a little more explanation since it is often a source of confusion.
The last layer (the empty one) must always have one ‘tre region’. The maximum size of this region is 65535/2 * resolution (grid). If the map covers a large area, the selected grid may be too low to allow the desired ‘tre region’ to be created.
The maximum size of any object strictly depends on the bit resolution. For resolution 24, the maximum size 1.5 metre * 65535. Similarly, for resolution 23, the maximum size 3 meter * 65535. This means that if the object is too big to fit into the given layer of the map, the bit resolution of this layer needs to be decreased so the layer can accept bigger objects.
Combine multiple .img files into one gmapsupp.img
- Run sendMap20 (rev 3.5)
- “Add maps” to get all your .img’s listed
- Hit “Create GMAPSUPP.IMG”
- Copy GMAPSUPP.IMG onto your microSD
- And you get nothing… This isn’t quite working yet…
- Instead of creating a gmapsupp.img, let’s just hit “Upload maps to GPS”
- That ends up with nothing as well..
So what I ended up doing was opening each map in GPSMapEdit (using File -> Add…), saving the whole thing as a .mp, and exporting that to a .img using cGPSmapper’s online compiler (when I tried to compile it on my computer I got “Error: Access violation at 0x00417C2C (tried to write to 0x00000000), program terminated.\\”). The finished product is Washington Roads and Waterways 2.
Upload your maps to the GPS unit
I was unable to open my MapCenter IMG with Garmin’s MapSource program. Instead I used sendMap (Version 2.8). Click “Add maps” and then “Upload selected maps to GPS”. Be careful with this, it looks like it could easily delete the existing basemaps.
Or you can copy the map onto your device manually. The GPSr expects to find a file called gmapsupp.img inside a folder called Garmin on the microSD card. Just copying a .img with a different filename onto the MicroSD card won’t work, but if you copy a .img onto the MicroSD card and rename it gmapsupp.img, the GPSr will see it. To access my microSD card directly I hit
menu -> menu -> setup -> interface -> USB Mass Storage on the GPSr. Although creating or replacing your gmapsupp.img file should in no way affect your basemaps, remember to take a backup of your old gmapsupp.img files before overwriting.
Even if you want to upload multiple maps, they all need to be bundled into one gmapsupp.img
When importing each map you need choose the color of the imported features along with which field to use as the name display on the map.
Not seeing what you expected? Try View -> Levels. Each level represents a different set of zoom levels on your GPSr. You have to be careful about the level when combining maps. You don’t want to put too much detail at too high a level, or your map will become too crowded. You might want to add major cities to levels 1 and 2, for example, but smaller cities only to level 0. Once while combining maps I ended up with an extra empty level inserted, which was easily removed. Levels are modified through File -> Map Properties -> Levels.
There doesn’t seem to be a way to really specify the exact destination coordinates of files you add. When combining data from different sources, this can result in your maps not aligning correctly. The only way to change the “Target bounding rectangle” during an import is with the “Datum” dropdown. I have no idea where this list is populated from or what the different values mean (many of which resemble foreign country names?), but they all land your map in about the right location. To get really exact I had to use GPSMapEdit’s Transform feature to adjust the original maps individually before importing. A couple maps I have tried to open had bogus numbers in the “Bounding rectange in source units”; I haven’t found any way to salvage these maps. (Update: I’ve figured some of this out here.)
So far I’ve had success opening MapCenter IMG’s and .shp files. Even though .shp doesn’t show up on GPSMapEdit’s list of “All supported files”, GPSMapEdit has no problem with these. Actually, when working with an existing multi-level map, if you add a single-level .mp, it will only add the single level. If you add a single-level .shp map, it will extrapolate the existing level into the higher level at appropriate levels of detail–very nice! So remember, open you multi-level maps first, and then add your single-level maps.
cGpsMapper (Windows, Linux, on-line; free, shareware, comercial)
Compiles Polish format files into Garmin IMG files. Integrates with GPSMapEdit. After running over an hour compiling a map, I got “Error: Access violation at 0x00417C2C (tried to write to 0x00000000), program terminated.” Fortunately, cGpsMapper also hosts MapCenter, which allows you to upload Polish files and they will compile them for you. MapCenter was able to successfully compile the map that crashed cGpsMapper on my system. Plus, it can save you a couple hours of CPU time. The catch is that then the maps become publicly available, which for me isn’t a bad thing at all.
The instructions are a little vague: to upload you own maps save your .mp as build.mp (lowercase), zip it, create an account, and then just fill out the “Add new map” form. Large maps can take a couple of days to show up, depending on the load. You’ll know your map is ready when a “[build log]” link shows up under your map. If there’s a “[binary IMG – xxk]” link as well, your map compiled successfully. If not, check the log to see what went wrong.
These are the same folks who make sendMap available. Note that http://cgpsmapper.com/ has been updated more recently than http://gps.chrisb.org/en/main.htm.
“ArcExplorer is a lightweight GIS data viewer written in Java that is used to perform basic GIS functions (e.g., view, navigate, and query). It is a downloadable application that operates in a stand-alone environment and does not need to connect to a server. ArcExplorer is heavily used in the education world and runs on both Windows and Apple Macintosh computers.” And Linux! Great viewer, but you can’t save maps as anything other than ArcXML or JPG.
Here’s what I’m still playing with:
The National Map
“The National Map Viewer currently supports download of vector (line-based) features and raster (image-based) data where available…. Datasets will be clipped to the current viewer map extent.” This creates ESRI shapefiles.
Online shape file viewer.
“The MapWindow application is a free, extensible, geographic information system (GIS).”
“Convert GPS or GPX file to ESRI Shape file”.
Washington map sources have moved here.
File format notes have moved here.