USGS Maps download FREE

[JOD]

I didn't look to see if this has been posted in the past. I was researching some data for an associate this morning and came across this link USGS PDF Maps. You can locate a map in the US and download the file. It's not geo-referenced but most of us don't need that capability. It does give you the ability to save, view, and print the USGS quad sheet for FREE. I love that word. Your tax $$'s at work.

 

[DougPaul]

The link doesn't work for me: it simply returns a "Your session has Expired due to inactivity, please login again" message.

http://store.usgs.gov/ looks like it can get you started.

Most USGS 24/25K topos are also freely available through http://libremap.org/.

The USGS had the topo maps scanned (DRGs*), but had not made DRGs freely available on their websites. (The maps are public domain and were paid for by taxes.)

* The original scans were at 250 DPI and are available in the form of TIFF files with registration info (.tfw files).

Doug

 

[JOD]

hmmm maps...

DougPaul,

Thanks for noticing the broken link. The link you provided is the start. Select "Map Locator" and you will be directed to the GeoPDF topo maps.

The USGS source seems to be pretty straight forward to identifying the location and quad sheets. The maps here are also available in sizes, i.e. 7.5 minute, 30 minute, and 100 minute. They're easy to print too.

For some reason my company has seen to it that I can't download files from libremap. I've tried to explain I need to access the files for projects.

I use DRG's at work, I prefer .sid to .tif if given a choice. The "sid" uses .sdw similar to the .tfw file. Most users don't have the software to truly use the geo-referenced files.

Jim

 

[DougPaul]

Thanks for noticing the broken link. The link you provided is the start. Select "Map Locator" and you will be directed to the GeoPDF topo maps.

I haven't checked them out yet--I'll have to see how the pdf maps compare to the tiff maps. (Ease of manipulation, etc)

The USGS source seems to be pretty straight forward to identifying the location and quad sheets. The maps here are also available in sizes, i.e. 7.5 minute, 30 minute, and 100 minute. They're easy to print too.

Sounds good--at times I've been able to find one scale, but not another.

For some reason my company has seen to it that I can't download files from libremap. I've tried to explain I need to access the files for projects.

Seems odd. Maybe they have a general block on large image files. A number of states and libraries have topos available online. If you can find the file name through libremap, then a Google search can often locate a copy somewhere else.

I use DRG's at work, I prefer .sid to .tif if given a choice. The "sid" uses .sdw similar to the .tfw file. Most users don't have the software to truly use the geo-referenced files.

Agreed. The MrSid stuff is not very common for non-professional users. However, there are programs such as www.oziexplorer.com that can use the registration info. I mostly just use image display and editing software so .tif (perhaps converted to .png) is fine for me.

Doug

 

[DougPaul]

Just checked the pdf maps out. Third rate.

The pdf is downsampled by a factor of 3.47 and is of terrible quality. If you display one of the original .tif files alongside the corresponding .pdf the difference is striking.

I have copies of some of the originals and here is a comparison:

k42071d3
 
format  pixels           size
------  ---------       ------
zip*                     5.9MB
tif     9738x6232       14.1MB
tif.gz  9738x6232        6.0MB
png     9738x6232        6.2MB
gif     9738x6232        6.0MB

pdf     2805x1795       11.5MB

* original distribution format: includes image (.tif), registration (.tfw), and description (.fgd) files
All of the first group were derived from the zip file.

What a waste! Why don't they just make the .zip files available and be done with it...

Doug

 

[Whiteman]

More Map Resources

I was bouncing around on the internet in my daily "Let's not start work yet" part of the day, and came across a new (to me anyway) map resource:

geonames.usgs.gov​

The pages link out to a number of free topo map services.

Cheers.

 

[1HappyHiker]

I was bouncing around on the internet in my daily "Let's not start work yet" part of the day

I’m familiar with that!

. . . and came across a new (to me anyway) map resource:

geonames.usgs.gov​

The pages link out to a number of free topo map services.

Thanks for posting this link. Will have to spend some more time at it later, but at first glance, it looks like it provides a convenient way to access multiple online mapping resources to examine a specified location.