Messages

If your NED data was pre-December, you may want to redownload some of it as portions of northern Maine were replaced with 'true 10m' versus the 'resample 30m' which was available previous to then.  See: http://gisdata.usgs.net/website/usgs_gn_ned_dsi/viewer.htm

I would say you need to divide your data\area into smaller sized 'subarea'; probably 15x15 minute quads for 20 foot contours in the Southern Appalachians.  My file sizes for 20ft contours in that area were over 20% bigger than anywhere in the Western mountains.  You do not have as much hydro (or contours) as I processed for the 50 States; the key to handling it is to divide it into smaller manageable 'quads'.  I would say your area is way to large for a single .img file, but could be easily handled in 200-300 smaller (15x15) quads.  It would just be another mapset in MapSource where you could combine part of all of it with other mapsets to be sent to the GPSr in a single gmapsupp.img file. 

In my experience for contours the .img file sizes are about 6% of the .mp file sizes.

Do you mean a 30x60 minute quad? 

I am using GM for contouring, etc., however, I would say your spatial dimension (30x60) needs to reflect the contour interval you are using.  If the resulting .mp files are as large as 600Mb, you need to go to smaller sized .mp files (15x15 minute) and/or use a larger contour interval (40 versus 10 feet, etc.).

What geographic area are you contouring and at what contour interval?

Using 30m, 10m, or 3m from the Seamless Server should not make much of a difference in the .mp file sizes.  However, the grid cell spacing has an effect on what the smallest appropriate
contour interval is for any given slope angle.

Simple is never simple.  I do not have a Legend so can not be specific about that model.  The different models are designed to be best in different fields.  The free maps have the roads, but making them routable (turn by turn directions, etc) in much more complex - best to check for your specific area.  I believe most of the smaller Garmin units use a 'micro'/phone SD card, not a full sized SD card.  About $10 for 1Gb, $15+ for 2Gb, over 2Gb are not fully support by Garmin.
Need to put the maps on the card via MapSource, SendMap, etc.  USB to the GPSr (slow and sometimes not to reliable) or via multicard reader or slot in the computer if the micro-card came with an adapter to the full sized SD card. 

I'd say you would do OK with a Legend hcx for the price.  The 'c' models for color for the maps; the 'x' models for the removable memory card to store the maps.  Probably figure 1-3Mb of memory per 7 1/2 quad area depending on the area and level of detail available.  I think the internal memory for the non-x units is in the 16-32Mb range.  If you activities may get the unit wet, you may want to consider a 'water-proof' unit.  If you have an REI, or other store which carries various units nearby, go check them out - the button controls, etc differ in size and placement on the models.

I emailed Census about realignment and they said all counties had been.  There are two sections of I25 between Denver and Colorado Springs that are coded as a lesser road type.  Census created this data set to assist in taking the Census - roads with housing (addresses) are important, others not so much so.
 
OZ, hope you enjoyed the break last weekend when the USGS servers were down.

I am using GM in a Vista environment.  At 75-80% memory usage, GM terminates without a message. 

I just downloaded a small 30m NED as a test.  The site is very slow in going from screen to screen and for the extract process, however the download itself was at full DSL speed.

Has anyone used GM10 to view/process the NHD data in 'Pre-staged personal geodatabases'?

I tried a couple of files but they only show lines,  points and basin? polygons; no waterbody nor area info.  Mike at GM thinks it is because that info was not included, but the files are not of much use without it.

BTW - the NHD viewer page has the 'systems unavailable'  for Dec 6 message.

I downloaded the National file after yesterday mornings post.  Site is 'not found' this morning.
This file has two additional fields at the end for original date and modified date.  It also lacks any data for Alaska or Hawaii.

Another GNIS.  This is the fourth one I have seen in the past 12 months.

Make that SD card from Garmin read-only if you can, it can be trashed and is not replacable.
MapSource will make a gmapsupp.img file using the data you have selected from any/all of the data sets you have installed in it.  Only one file with that name can be on the card.  If you later want to add more data, the gmapsupp.img file will need to be recreated.  You can have more than one .img on the unit, but only the one named gmapsupp.img will be used - with a PDA or laptop you could rename files.  I believe the Garmin SD card is locked, so it may not be possible to combine their data with the make-your-own data.

I do not have anything on the computer for a quick screenshot in GM.  However, using GPSMapEdit found at:
NM 54881491 file, 6400ft @ 34 19.521 & 106 00.267
WY 88201003 file, 9840ft @ 44 57.464 & 109 33.389
CO 88200004 file, 7920ft @ 40 42.374 & 107 07.815
also in the ME data

They are much easier to find in GM with just contour lines and not having to zoom in to have the small features show.  I suspect it is caused by two adjacent grid points having an elevation which is just a tiny amount on the other side of a contour interval than the other points around the area.
Probably a somewhat similiar reason for the small triangles.

Yes, a GM script file can process and output data without displaying it on the screen (much faster that way for huge files).  It does take time to load the file(s), it just does not require the additional time to display the data before processing (ie. contouring) or outputing (ie mp files).

It is a working system use by USGS and State agencies, so our outside requests get low priority.
I have had to waite nearly a week to get those emails.  Sometimes the request buffer hangs; I have had a few come back a month later - long after the rerequest was answeres.  Send them an email about your requests - may be a stuck buffer, or something else on there end.

I do the same with a script file in GM.  I was curious to know if you found a program that contoured without creating those unslightly short 2 point line segments.  Sorry to be off-topic; I have not mastered how to send an email to you on your site.

Oz,
  What is your reason for not using GM for contouring?