Northeast topo maps...

[slyder01]

In the maps section i see there are  parts 1of 3 and parts 3 of 3 to the northeast topo maps. Is there a parts 2 of 3? 
Thanks

[maps4gps]

Yes.  See: http://www.gpsfiledepot.com/maps/view/201/

[slyder01]

Thanks,,,
How do i know if they are the 24k, it doesnt say.
I'm just assuming they are because there are 3 parts to the d/l

[maps4gps]

I would think it would be like the others (part or the regions).

Depends on how 24k is defined.  I would say that none of the mapsets here, and likely not elsewhere, are 24k in every aspect (as on a USGS 24k quad) - including mine.  As an example, about 50% of the USGS printed 24k topo quads use a contour interal of less than 20 feet.

[slyder01]

the 24k i am referring to is this one on this link
https://buy.garmin.com/shop/shop.do?pID=35411 
thanks

[Boyd]

That is an expensive Garmin product that will be different from any of the maps on this site. Most notably, the road data comes from Navteq, which is going to be more accurate than the public domain data that we can access here. The roads are also routable (can provide turn by turn directions and address search).

OTOH, their product may not contain as many trails and dirt roads, since Navteq is more interested in places where people live and commute.

I think the term "24k" is going to be pretty subjective when talking about GPS maps, as maps4gps has said. It really just means a paper map that is drawn at a scale of 1:24,000. Those maps don't necessarily look so great when you magnify them to scales you might use when hiking with a GPS. Here are a couple Oregon screenshots from the other day that show the "real" USGS 24k map from my Delaware Water Gap custom map vs my Map of New Jersey.

[maps4gps]

Garmin would have to be specific (in detail) about what they mean by ' highest level of topographic detail available, with maps comparable to 1:24,000 scale USGS maps.' before a judgement/comparison could be made.  However, I doubt they would ever advertise their product(s) as not being as 'good' as something available elsewere.

[slyder01]

If my screen is going to look like the one above after putting in these maps, I'll just stick with the 100k that is already preloaded in my 450t. I thought by having the 24k the rosultion is would better, especially when zoomed in. 

Thanks guys

[Boyd]

The screenshot on the left is a real USGS 24k topo map. You can't tell how accurate the 100k map is by just looking at it in a vacuum. The road data on Garmin's 100k topo maps can be pretty terrible in many cases here is one example.




Compare that to City Navigator below, which places the roads in the correct place. The streets in US topo are off by more than a block.




Unfortunately, many of the maps on this site are based on the same free data that Garmin used with their 100k topo's, although there are some which have used revised data that is more accurate. The only way to know which is better is to install the map on your computer and compare them. I used Garmin Basecamp with BirdsEye to create the images above.

Also note that the correct streets in the second image come from Navteq data, and this is what Garmin has used in their own 24k topo products.

[maps4gps]

Resolution is dependent on the bit-level the vector data is defined at.
I have been told that Garmin usually uses 23 which is about the 800' zoom level.
The max we can get using cgpsmapper to compile the maps is bit-level 24, or about the 500' zoom level.
Zooming-in more than these values simply equally spreads the data.

The 24ks are more detailed than the 100ks by having more features shown, closer spaced points describing the area and line features and more accurate coordinates..

The accuracy for the printed USGS topo quads is generally around 20' for the 24ks and 80' for the 100ks.

[slyder01]

Thanks everyone, now I'm understanding the maps