Introducing the Landscape of the United States series

[Boyd]

Just in time for Independence Day! Explore the changing face of America during the past 40 years with nine new maps covering the whole country. They use historical land cover data and 3d terrain to create an effect similar to aerial photography. The resolution is pretty low (about 125 feet per pixel) so you won't see small details, but they do a good job of capturing regional changes over time.

This was sort of an unplanned "project of opportunity" for me. Two weeks ago I was looking at data from the National Land Cover Database (NLCD) and noticed they have recently re-processed their historical data for every year between 1985 and 2024. This seemed like a nice holiday-themed project, so I dropped everything and have just now finished (each map took about 22 hours just to render). More information about how these maps were made here, or just click the map info button in the app

Haven't spent a lot of time pouring over all these maps yet but have a few initial impressions. For starters, you can see a fair amount of development in South Jersey between 1985-2024, but most of it appears to have displaced agriculture and not forests. You can compare 1985 to 2024 here

https://boydsmaps.com/sync/#11/39.824632/-74.959226/nlcd1985/0/0/nlcd2024/11/0/0

But our poor little state is so heavily developed already, it doesn't looks as significant as I would have expected. The place that really surprised me is Atlanta, GA: that area has just exploded over the past 40 years. I guess it's good for the economy, but... wow.

https://boydsmaps.com/sync/#10/33.924012/-84.253660/nlcd1985/0/0/nlcd2024/10/0/0

Another example of suburban sprawl that surprised me is Boise, ID.

https://boydsmaps.com/sync/#11/43.608954/-116.456349/nlcd1985/0/0/nlcd2024/11/0/0

One that didn't suprise me is Las Vegas (notice how Lake Powell is shrinking too)

https://boydsmaps.com/sync/#11/36.169633/-115.144856/nlcd1985/0/0/nlcd2024/11/0/0

And it's also sad to see the receding waters at Salt Lake City

https://boydsmaps.com/sync/#9/41.123111/-112.532857/nlcd1985/0/0/nlcd2024/9/0/0

It's a big country and there's a lot more here for all of us to discover. Have not made a final decision yet, but will probably add more of these maps - maybe even all 40. Seems like this might be a good resource for people who want to find out which year the dam broke, when there was a forest fire, etc.

As usual, you may need to clear your broswer cache to see the new maps. This is covered towards the end of the help file.

Enjoy - and happy Fourth of July!

 

[bobpbx]

I recall reading several times about Atlanta and the beautiful trees and decent weather. I'll have to run through that area some time (yeah, sure bob, like you have many years left).

 

[Boyd]

Just added the 2016, 2017, 2018, 2019, 2021, 2022 and 2023 maps to this series, so we now have maps for every year from 2015 - 2024. Will continue working my way down the list until there's a map for every year, going all the way back to 1985.

I also have legacy (pre-LandSat) USGS landcover data which is cited as 1970-1985. Apparently, this is the old hand-drawn maps where they traced outlines on aerial photographs to show different landcover types. At some point during the late 1970's - early 80's they digitized all this which was a big project that took years, trying to correct problems, etc. I guess they just called it quits after they had the satellite data, so it isn't exactly clear what time period this legacy dataset represents. My assumption is that it's 70's based and they spent the later years just digitizing and cleaning it up, but we will have to wait until the map is done to try and figure that out. Anyway, it's very different in style from the Landsat-based maps, so it will be hard to make direct comparisons, but still worth including from a historical point of view (as the first USGS digital landcover database). I'll include this with the next upload in a few more days. If I can keep up the pace, the whole series will be done in late July.