No Disconnect

1. Add all layers at once. Add to level 0.
2. Properties
   1. add a map ID, add a map name, convert to meters
3. Levels Tabl
   1. add up to Level5
   2. make Zoom0=0 … Zoom5=5
   3. make “Bits” descending
4. Select minor contours, right-click, Join Objects
5. Extend to level 1 (i.e., GPS Zoom 200 m – 300 m)
6. Select intermediate contours, right-click, Join Objects
7. Extend to level 3 (i.e., GPS Zoom 800 m – 1200 m)
8. Select major contours, right-click, Join Objects
9. Extend to level 5 (i.e., GPS Zoom 1200 km)

Well, this took long enough.

Broad Strokes

1. Data from the Shuttle Radar Topography Mission (best taken from CGIAR).
2. Use GDAL (gdal_translate) to convert to GMT‘s .grd format.
3. Use GMT’s grdcut to cut out a region of interest.
4. Use GDAL (gdal_contour) to create a contour map, in ESRI Shapefile format.
5. Open GPSMapEdit, import said Shapefile, tweak environment parameters extensively. Save as Polish-format .mp file; export as Garmin .img file.
6. Use MapSetToolKit to install the .img file as a map that MapSource can see.
7. Use MapSource to send the file to the GPS.

Tricky Bits

• Steps 1 – 4 are pain-free.
• Step 2
  • File | Import | Shapefile. In the “From field” tab the labels must be clicked on, for some reason. Click. Click. Make sure the datum and coordinate system are correct.
  • Under File | Map Properties. Enter a unique 8-digit numeric key in “ID.” Give the map a name.
  • Tricky things to do under the “Levels” tab:
    • A “level” is a zoom level. Level0 is the most detailed; Level8 or so the least detailed. Map objects will only be visible at levels for which are not specified, or for levels that are not specified.
    • So, add as many levels, plus one, as you want your map to be visible in. The last level must be blank.
    • Moreover, in the “Bits” field of the “Level Settings” dialog box, starting from Level0, each successive level must use fewer bits than the one above it.
  • Close out the “Map Properties” dialog.
  • Select all of the contours. Right click. Modify | Extend All Elements up to Level — and enter in the number of levels minus 1. (The highest-level level must be empty.)
• Step 7. Described here.

Remaining Work

1. Figuring out what contour intervals are appropriate for which zoom levels.
2. Making it look better.

Credit/help/inspiration: here and here.

Copying a map to my Garmin should be as easy as copying an MP3 to my MP3 player. Here’s how it really works:

There are things called “mapsets” — Garmin products, or pretend Garmin products. (Information about mapsets is stored in the computer registry, so of course people have figured out how to fake the format. This is what MapSetToolkit does; you give it an .img file, and it fakes out Mapsource into thinking that your .img file is a real Garmin product.)

The idea behind MapSource is that you’re working with a “Garmin GPS Database.” What’s in the database is what’s in the panel at the left of the screen. Not every map in every mapset is in the database. This was confusing when I was trying to transfer maps to the Garmin. How does one add a map to the database?

1. Select the desired mapset with the “Select the desired product” drop-down at the upper left corner.
2. Make sure the “Map Tool” button is checked. (Inexplicably the symbol is a yellow polygon.)
3. Click the map you want to add in the map window.

Thereafter it’s a simple matter of, Do Transfer | Send to device…. The really surprising thing is that you have to select all of the products you want to send to the device, visually. (For such a slick device the software is not great.)

Whew. Herculean task. Starting from a spreadsheet with labels, latitudes, and longitudes…

1. Convert the spreadsheet to a CSV file.
2. Convert the CSV to a vanilla XML-style record using something like this.
3. Convert the vanilla XML to KML using a simple XSLT stylesheet.
4. Convert KML to GPX using GPSBabel.
5. GPX goes into MapSource; MapSource sends it to the GPS.

Steps 2 or 3 are a bit schematic. Oh well; it’s just a matter of looking up an example KML file, like the one Google provides, to be able to write the XSLT file. I suppose it would also be possible to go straight to KML (or GPX, for that matter).

Okay, I just checked, and GPX has a really straightforward format.

Whatever. With GIS & GPS, if it doesn’t take you five steps, through three formats, one of them proprietary/undocumented, you’re not doing it properly.

OpenStreetMap has surprisingly good street map coverage. After signing in it is possible to download XML data for a region from their site. Then use Mkgmap to convert the XML data into Garmin .img format. Then use the free program MAPupload to load it into my Garmin. So nice when these things are easy.

JOSM seems worthy of further exploration…

Directions from this site.

Not that this is really the point of a GPS, but it’s nice for when I want to sit still and fiddle with it. I don’t recall seeing this mentioned in the documentation.

There is a free way to convert from the “Polish format” (for cgpsmapper) into something that can be loaded into Garmin. Instructions here. You use a free tool called MapsetToolkit. Bit of a clunky interface.

I’ve got GeoTIFFs from the CGIAR SRTM V4 data (i.e., the SRTM data, with the gaps filled). Previously I sent the data through Matlab and then through grdraster to get them into GMT format, but GDAL offers a convenient way to do this:

gdal_translate -of GMT /GIS/srtm/srtm_14_06.tif /GIS/srtm/srtm_14_06.grd

Wow. Easy. Also:

gdal_translate -of GMT /GIS/gtopo30/E020N90.DEM /GIS/gtopo30/E020N90.grd

I’m looking at the GDAL and OGR utilities/libraries. GDAL provide a couple of different raster tools, and has a lot of capacity to convert files.  I note that it can generate contours from raster data. OGR is vector-oriented, and does a lot of conversions as well (including GML and KML).

Tests forthcoming…

GPSBabel “converts waypoints, tracks, and routes between popular GPS receivers and mapping programs.” Not the ultimate in conversions, but it’ll get the data to KML, which is far enough for me. Garmin’s Mapsource has a text export option, but nothing that I wanted to have to parse afterwards.

I’ll need to write more once I’ve played around with it.