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News: Northwest Topos v0.26 now available (December 12, 2013)
 
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Author Topic: Difference Between These Topos and the File Depot One?  (Read 2574 times)
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GrnXnham
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« on: September 16, 2010, 10:50:35 pm »

I had been using these topos from file depot:

http://www.gpsfiledepot.com/maps/view/95/

Jon, is there any difference between your Topos and these that you know of? I have found a few areas of WA where topo info/data is completely missing from the complete download at File Depot.

Looks like the download from File Depot is much smaller than yours. Something has to be missing from this version. I'm just not sure what.
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Gsnorgathon
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« Reply #1 on: September 17, 2010, 12:19:40 am »

Those topos won't have the NW Trails, for one; though I don't know if that would account for much of the size difference.
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Moun10Bike
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« Reply #2 on: September 17, 2010, 10:14:44 am »

Jon, is there any difference between your Topos and these that you know of?

Yes - tons, IMHO.  It really takes a lot of work to do maps right and even then you have errors all over the place.  I like to think that I put extra effort into my maps that others don't, but I'll let you determine that based on your own personal impressions of the various mapsets.

First, on the issue of the map size.  The biggest difference is the coverage area.  Washington 24k Topo covers only Washington, while Northwest Topos covers all of Washington, the Idaho Panhandle, about 1/3 of Oregon now, and increasing portions of BC.  Here's a visual comparison of the two zoomed out to show all extent:



The size will continue to increase as I finish Oregon and work into expand into the surrounding regions.

Another difference in the two mapsets are the contour intervals.  I have worked to insure that the intervals in Northwest Topos match (or exceed) what the USGS determined was the best interval for any given quad.  Most mapsets out there just pick one interval for the entire mapset (it's easier).  This becomes noticeable in areas where the elevation differences are not as great as in the mountains and more detail is handy.  For example, here is a comparison of the area around Tokul (near Snoqualmie Falls) where Northwest Topos is using 20-foot intervals vs. Washington 24k Topo's 40-foot intervals:



Another thing that separates Northwest Topos from other mapsets out there is that I have gone to considerable efforts to obtain and incorporate land ownership/management data.  This includes areas that often fall off of the radar like local and state parks, etc.  For example, here is a shot of the Discovery Park area in Seattle.  You can see that Northwest Topos displays the park area and details while most other mapsets just rely on national-scale areas:



Now, regarding quality.  You probably noticed the lack of water around Discovery Park in Washington 24k Topo in the above comparison shot.  There is something about Puget Sound in the USGS hydrology data that causes the map creation tools to hiccup.  I ran into the issue when I saw that the Sound was not displaying in Northwest Topos.  It took a significant amount of investigation and trial-and-error before I was able to get the Sound to display properly.  Every other user-created mapset that I have seen out there has not made that effort:



Similarly, many other mapsets have completely overlooked the fact that a whole section of the Strait of Juan de Fuca and shoreline along the Olympic Peninsula east of Sequim is missing from the government data sources.  I manually digitized that data using aerial imagery and topo maps.

For my last point, I'll mention that while it is easiest to just grab data from government sources and throw it quickly into a mapset, it often takes some effort to determine if everything should be displayed, or how it should be displayed.  Case in point: the National Hydrology Dataset contains "extra" lines in it that are meant to show flow, but do not represent actual watercourses.  These are called artificial paths and are used to indicate how streams combine in a lake, or identify river flows when the rivers themselves are large and represented as polygons rather than lines.  These artificial paths are useful for some GIS analyses but serve no use on maps.  I have taken the effort to remove these from my dataset and, since they are the only source for river names in the dataset (the waterbodies themselves are for whatever reason unnamed), apply the names from the artificial paths to my polygonal rivers.  Other mapsets have not done this, so you see "streams" flowing through lakes and down rivers:



Oh yeah, and Northwest Topos contains all of the trails collected and integrated from Northwest Trails!

There are a bunch of other things that I have put into trying to make Northwest Topos as good as it can be, and I hope the results will speak for themselves.
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Jon
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« Reply #3 on: September 17, 2010, 03:02:27 pm »

Oh yeah, and Northwest Topos contains all of the trails collected and integrated from Northwest Trails!

There are a bunch of other things that I have put into trying to make Northwest Topos as good as it can be, and I hope the results will speak for themselves.

Definitely - head and shoulders above anything else out there, and still free. Can't say it enough: Thanks Jon!
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Gsnorgathon
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« Reply #4 on: September 17, 2010, 03:42:30 pm »

Jon - That's a great marketing blurb! Perhaps you should put that on the main page - or at least link to that post.
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GrnXnham
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« Reply #5 on: September 17, 2010, 10:02:11 pm »


Oh yeah, and Northwest Topos contains all of the trails collected and integrated from Northwest Trails!



One clarification here, Jon. You say it contains ALL of the trails from NW Trails? Does that include the trails from Montana, Alaska, and Oregon that are outside of the map area represented by NW Topos or will I need to load those states separately?

Also, if I have NW Topos loaded on my GPS, is it possible to turn off the topos but leave the NW Trails on? I do this from time to time with Washington 24K topo in order to accelerate screen redraws and also sometimes with all the topo lines on there it can be hard to see the roads/trails. In other words, you say the two are "integrated" but is it still possible to separate them?
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Moun10Bike
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« Reply #6 on: September 17, 2010, 10:34:06 pm »

You say it contains ALL of the trails from NW Trails? Does that include the trails from Montana, Alaska, and Oregon that are outside of the map area represented by NW Topos or will I need to load those states separately?

No, it only includes the trails covered by the current tile set.

Quote
Also, if I have NW Topos loaded on my GPS, is it possible to turn off the topos but leave the NW Trails on? I do this from time to time with Washington 24K topo in order to accelerate screen redraws and also sometimes with all the topo lines on there it can be hard to see the roads/trails. In other words, you say the two are "integrated" but is it still possible to separate them?

Yes, they are treated as completely separate mapsets (they are, as they have different internal IDs) and so they can be turned on or off separately from one another.
« Last Edit: September 17, 2010, 10:43:15 pm by Moun10Bike » Logged

Jon
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« Reply #7 on: September 18, 2010, 07:46:28 am »

Also, if I have NW Topos loaded on my GPS, is it possible to turn off the topos but leave the NW Trails on? I do this from time to time with Washington 24K topo in order to accelerate screen redraws and also sometimes with all the topo lines on there it can be hard to see the roads/trails. In other words, you say the two are "integrated" but is it still possible to separate them?

Yes, they are treated as completely separate mapsets (they are, as they have different internal IDs) and so they can be turned on or off separately from one another.

Yes - but to clarify, you need both NW Trails and NW Topos installed if you want to turn off the topos and still have the trails show up. (That also gets you trails for areas not yet covered by the topos.)
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GrnXnham
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« Reply #8 on: September 18, 2010, 08:49:40 am »

Thank you for the clarification. I will install both.
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