Messages

The demo version of G-Raster will convert a small section of the GeoPDF to GeoTiff format, which can then be imported directly into G-Raster's Custom Map section; registered version ($5) is currently required for full conversion. This limitation will be removed in the next release, as the GeoPDF converter has problems with some GeoPDF files (non-standard headers), and I don't want people paying for a program that doesn't always work for every GeoPDF file. An alternative to G-Raster (and for non-geo PDF files) is to convert them to image format with the free program GeoPDF creator, use Google Earth to calibrate the image and save it as a KMZ file, then "tile" it with a program like G-Raster, mapc2mapc or Global Mapper.

You could also create an image overlay for Google Earth using your high-res aerial photo.

There's a product called Sticker Lifter (from the makers of Goo Gone) that might be worth a shot. Don't know how well it would work, and whether it would affect the touch screen.

So, in order to make a custom map with 500 tiles using g-raster, it would first be necessary to use some other software to split it into 5 smaller images and then convert each of those?

G-Raster comes with a map cropper, so you could do it in the program itself right now. But you've given me an idea to add a quick-and-dirty "map chopper" utility that will take a large map file and convert it into smaller 100-tile-compatible chunks that G-Raster can process in its current state. I'll see what I can do.

Standard version of G-Raster limits you to 100 tiles, but this is because the graphics library I use has major memory management issues that causes it to choke on large images. The update page has a hacked version that can do images that generate >250 tiles, but it's flaky and may not work on all raster maps. I'm working on a full rewrite that will eliminate the old graphics library, and lift the 100-tile restriction for the standard version, but it will take a while.

Maps converted from raster to vector using Moagu's BMap2MP utility should work on the Montana and related units - I've used them successfully on my 62s. But unless you've hit the 100 or 500 tile limit, Custom Maps are a far better choice in terms of ease of creation and quality. Moagu (and BMap2MP) are hacks mainly intended for older units that don't support Custom Maps.

The native datum for the maps is WGS84, but you can choose any datum you need to use for either BaseCamp or your GPSr; both the software and the GPSr will automatically convert from WGS84 to whichever datum you select. Most modern datums are pretty close to WGS84 just about everywhere, so that's the best default choice; e.g. NAD83 doesn't differ from WGS84 more than meter anywhere in the continental US, less than the best stated Garmin GPS accuracy. But if you're using an older USGS topographic map and want to match coordinates on the map to the GPS, you should set it to NAD27 datum, as the difference in position between WGS84 and NAD27 can be hundreds of meters.

Just remember that the native coordinate system for GPS is geographic coordinates (lat/long), WGS84 datum; all waypoints and track points are recorded/saved in that format. If you choose a different coordinate system or datum, it is converted from geographic/WGS84 to be displayed, but internally it's kept in geographic/WGS84 coordinates.

Moagu is a hack for older Garmins; a modestly clever hack, but with serious limitations. The limit on image size is due to limitations in the graphics library that I used; for images larger than 100 megapixels, the program is likely to choke. I hope to remedy this ultimately for my G-Raster program, but given the increasingly shrinking market for Moagu, it's unlikely to happen for that program.

It sounds like you're using the original Moagu format, which is a full point-by-point vectorization of the raster image into points. Decent for accurate reproduction, but painfully slow on any image that doesn't have mostly white as a background color; doubly so if you're not using one of the older faster Garmins, like the 60Cx or 76Cx. Resizing the image is unlikely to help, as it's the Garmin screen pixel density that affects display speed, not the pixel density of the original image. To get the image to display at a lower zoom level, set the "Detail" setting from Normal to High (but be prepared for even slower draw speeds).

I would recommend using Moagu's built-in BMap2MP GUI, as that's a front-end for a raster-to-vector conversion based on polygons, which will display much faster than a point-by-point (with some image degradation). The tutorial on this site should walk you through using that utility, and you will be much happier with the display speed, even if it will still be pretty slow. In either case, you will see some degradation of the image quality; can't be helped. You might try the MapWel raster to vector converter, as it seems to work somewhat better than BMap2Mp.

Finally, if you absolutely need these charts, you will absolutely get better results using actual raster charts on the newer generation of Garmins. The eTrex 20 is available for less than $200, the Oregon 450 is often on sale for about $250. And the newer Garmin GPSMap 78 series is designed for marine use (it floats).

I'm not doing routable maps, just maps with custom TYP files (including subtypes) and lots of polygons. I've been using release 1995, though I may try the most recent release series (21xx) in the near future.

Have you tried using mkgmap to compile these maps? As long as you set the memory usable by Java to a high-enough level (use the Java control panel), it seems to do better on files with a large number of polygons than cgpsmapper, and it's faster as well.

Every time you upload maps using BaseCamp, it creates a file called "gmapsupp.img" on your GPS unit that contains the selected maps. If you upload another set of maps, it will also upload them to the "gmapsupp.img" file, wiping out the previous data. However, you can keep the first mapset by changing its name to something else descriptive, e.g. "MN_topo.img" (you need to keep the ".img" file extension); it will show up in your map list as "MN_topo". Keep doing this with successive "gmapsupp.img" files.

You can download small sample sections of BirdsEye imagery for free using BaseCamp, so you can check it out. My personal opinion is that the aerial imagery isn't top-quality, and the image contrast can be so low that it's difficult to pick out details when viewed in sunlight. The topographic maps, on the other hand, look very good IMHO. While you can load topos with Custom Maps, you're limited to only 100 tiles; the convenience of BirdsEye topo maps along with the ability to cover much wider areas probably makes them worth the money.

If you ever use G-Raster again for topo maps (or any other kind), you can get more maps on your unit with some simple adjustments:

- Loading a USGS topo map using the 1:24K topo map input type will automatically crop the collar of the map, which will let you get more maps on.

- You can also rescale the map to a slightly smaller size, which will result in fewer tiles with no major loss in image quality.

For example, using decollaring and a rescale factor of 1.7 on a USGS topo map, you'll be able to fit 6 quad maps under the 100-tile limit.

What programs have you tried? I'd suggest looking at GPSTrackMaker, DNRGarmin, OKMap and GPSBabel. Just opened a KML MyMaps files in OKMap, and it looked good.

And there are free text to GPX online converters at these sites:

http://www.gps-data-team.com/convert.php

http://gpsvisualizer.com

The free DNRGarmin program will take a text list of coordinates as input, and let you export them in GPX format for use in BaseCamp. Google "DNRGArmin" for the software page.