GIS Shapefile for Continental US
January 22, 2010 9:13 AM   Subscribe

Looking for a (free) continental US shapefile.

I'm using a graphing tool display geographic-based data on a map, and it uses GIS shapefiles for display. The data is by state, US-only, so I need a relevant shapefile to work with. My problem is that the only relevant shapefiles I've found include a correctly-sized Alaska, which is giant in proportion to its relevance to my data. I've come across this, which is closer to what I want, but it doesn't include coastal boundaries (only internal ones). My questions are:

- Is there a shapefile out there that only includes the continental US (I'm fine with excluding Alaska and Hawaii for this purpose)?
- Barring that, what's the easiest way to modify a shapefile by resizing the Alaska shape and changing it's map position? I'm not a GIS specialist, but I am a developer. Mac or Win is fine.
posted by mkultra to Technology (9 answers total) 1 user marked this as a favorite
Here's the coastline. And a direct link. It doesn't have internal boundaries, but it can be combined with the state bounds shapefile you already have.
posted by jedicus at 9:40 AM on January 22, 2010

Well, I'm no expert in this field, but maybe you can find what you need somewhere in here? Apologies if it's not as relevant as I think it is.

I also found this "map layer" from Hope it helps.
posted by Salvor Hardin at 9:47 AM on January 22, 2010

It doesn't have internal boundaries, but it can be combined with the state bounds shapefile you already have.

How would I go about doing that?
posted by mkultra at 9:56 AM on January 22, 2010

The National Atlas [] has tons of free, nation-wide GIS shapefiles. It's probably not the shapefile that you want to change, but rather the projection of the map. There are a handful of "USA Contiguous" projections that you can go through to find one you're happy with.
You can use a free utility like QGis to edit the shapefile and restrict it to just the contiguous US. There are some basic tutorials available to help get you started.
posted by yukonho at 10:00 AM on January 22, 2010

Why, I just needed one of those yesterday. I ended up using the North American Atlas - Political Boundaries shapefile from Geogratis in Canada. It does include those pesky Canadian provinces and territories, but they're pretty easy to ignore/remove.

Seconding QGIS. Works nicely on a Mac or PC. I'd recommend the 1.4 version.
posted by scruss at 10:04 AM on January 22, 2010

TIGER/Line Shapefiles
posted by desjardins at 10:36 AM on January 22, 2010

If you're looking for state boundaries within the US as well, would this shapefile from work for you?
posted by golden at 11:00 AM on January 22, 2010

Also, if you're looking for just the continental US and you have a shapefile with AK and HI you can easily delete features (states) in QGis.
posted by golden at 11:04 AM on January 22, 2010

Thanks for the help! Turns out I was using an older (way older) version of QGis that wouldn't even let me select/delete features properly. Using the new version, I was able to strip out AK and HI.
posted by mkultra at 1:31 PM on January 28, 2010

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