National Land Cover Data Set: when there’s no Local Land Use GIS data

Co-written by Aaron Herman

Finding land use land cover data is a pain. Unless your project is within an MPO/COG that has historic and current land use shapefiles that are easy for your GIS guru to access, you can be up a creek without a paddle when it comes to finding good land use data.

Despite the data challenges, many planners HAVE to have land use data for their projects. For example, over 90% percent of transportation environmental impact statements address land use impacts in their indirect impacts analyses according to this unscientific survey. So what should you do if your project is in an area that doesn’t have local land use data? Or what if you have a giant project area and the land use data set for one area doesn’t jive with the land use data set for another area?

USGS Land Use Data

If you can’t find good land use data from the typical local venues (I’ll blog about “typical local venues for land use data” next week), check out the US Geological Survey’s 2001 National Land Cover Data Set (or USGS NLCD 2001). The USGS 2001 National Land Cover Data Set is the latest, most accurate, nearest-to-complete and standardized land use coverage for the entire United States. Yup, you can get land cover data for the whole USA enchilada.

2001 National Land Cover Data Set

Positives of the USGS 2001 National Land Cover Data Set

  • Nationwide land use data for the entire United States
  • Standardized land use types makes for easy apples-to-apples comparisons
  • Have historic data & are working on more current data set (2006) for visualizing land use trends over time

There is a USGS NLCD 1992 data set. And the land use experts over at the Multi-Resolution Land Characteristics Consortium are working on a USGS NLCD 2006 data set. You can use these USGS National Land Cover Data Sets to visualize land use changes over time.

Visualizing Land Use Change Over Time with National Land Cover Data Sets
Visualizing Land Use Change Over Time with National Land Cover Data Sets

Negatives of the USGS 2001 National Land Cover Data Set

  • 2001 is old
  • National land use data won’t be as detailed or current as local land use data
  • The data is provided as a image. While it’s possible to convert the image to acreage estimates, it’s technically difficult to do and would involve custom scripting.

Head to Head Battle: Local Data vs. USGS 2001 National Land Cover Data

Generalized Land Use 2005, Twin Cities Metropolitan Council
Generalized Land Use 2005, Twin Cities Metropolitan Council
2001 NLCD Data
2001 NLCD Data

Let’s compare the land use data provided by Twin Cities’ Metropolitan Council and the USGS NLCD 2001. I was able to download Generalized Land Use 2005 data from the Metropolitan Council for the seven-county area. For comparison, displayed below is the USGS 2001 National Land Cover data for roughly the same area. These images are pretty small–if you need bigger images or want more information about land use land cover data sources, scroll down to the end of the blog post where you can get more information in a pdf.

You can get much more specified data with the local Metropolitan Council data set. For example, I can determine Single Family Attached versus Single Family Detached versus Mobile Homes using the Metropolitan Council’s data. The USGS 2001 National Land Cover data provides generalized data on Developed High Density, Developed Low Density and Developed Medium Density. But not every project area has good, accessible land use data like the Metropolitan Council data. And that’s where USGS 2001 National Land Cover Data comes in handy.

Bottom Line

If you have a small project in an area that has good local land use data, local data is your best bet. If you have a large project area (think multi-county, multi-MPO/COG, especially multi-state) or you can’t find good local data, then check out the USGS 2001 National Land Cover Data Set.

If you need more information about where to get land use land cover data, Aaron Herman researched and wrote an excellent whitepaper on the subject. This blog post is based on his research. If you want a pdf of his whitepaper, contact me here and I’ll send it to you.

Do you have another favorite back-up land use data set that you use? Leave a comment so we can check it out.

Road Miles by State

Photo by Dan Gold on Unsplash

This blog post was updated on April 30, 2021. I find myself googling for this data once a month or so. I just can’t seem to remember where to find it on the Federal Highway Administration’s website. Below are states by total 2019 lane miles–which is the most recent dataset available today and is dated September 2020.

Road Miles by State: Sorted from Most to Least

New York240,489
North Carolina229,011
North Dakota178,845
South Dakota166,635
South Carolina166,594
New Mexico150,216
New Jersey85,108
West Virginia80,167
New Hampshire33,391
Rhode Island12,664
District of Columbia3,445
Source: U.S. Department of Transportation Federal Highway Administration. Office of Highway Policy Information. Highway Statistics Series. Functional System Lane-Length – 2019. Released September 30, 2020. You can download an Excel or PDF version of this data here.

Pie Graph Showing 2019 Lane Miles by State
And just for fun, here’s a pie graph of this table.

Helpful Links with Road Miles by State data
If you need historic data like lane miles for 1980 to 2007, check out Functional System Data; Estimated Lane – Length page. If you need Function System data for 2008 (i.e. interstates, freeways, arterial, collectors and local), check out FHWA’s Functional System Lane-Length – 2008 Lane-Miles page.

And below are links to FHWA’s Functional System Lane-Length by year. You can download PDF and Excel versions of the data on these pages.

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