Saturday, October 19, 2013

New Land Management and Fire History Layers

I've recently added two new layers to CalTopo, both built built on government datasets but with homegrown rendering.

Northern California burning
The fire history layer shows wildfire activity since 2000.  There are some regional datasets that go back much further, but this was the best I could find for national coverage.  Fires are color-coded by year along a yellow-red spectrum, with yellow fires being the oldest and red being the newest.  Exact dates are listed in the map info pane at the bottom right.

I've tried to show both the year and incident name for all fires.  Large fires are labeled as you begin to zoom in, and then all fires at the lower zoom levels.  Unfortunately, in areas with overlapping fire perimeters, it can be hard to figure out which label belongs to which fire - and some of the overlapping incidents even share the same color.

Large incidents labeled at moderate zoom

The second layer shows public land management (technically, the "surface management agency").  While data for this layer is sourced directly from the government and seems reliable if a touch dated, hunters should verify with a second source - don't blame me if something's mislabeled!

A wide mix of agencies in Southern California
As you zoom in, the polygons change from opaque-ish to translucent with borders, just like the fire layer.  I chose not to label them as national forests were the only areas with unit designations, e.g. Tahoe National Forest; most areas are simply attributed to BLM or state ownership with no further information.

National Forest boundaries - have they ever made sense?
I'm open to modifying the colors used for various agencies.  While I tried to follow existing map conventions as best I could, there are only so many options available and I can see how some might cause confusion: the Bureau of Land Management and Bureau of Reclamation are both orange, but I don't know how similar their rules on activities like hunting and camping are.

Public land management in the continental US


  1. Looks like CalTopo is down this morning. :(

    1. Thanks for the heads up, Jim. Up and running now.

  2. great resource! fyi - the surface management agency layer is not working currently (access denied on all tile requests)...

    1. Thanks for the heads up. It had some hopefully temporary glitches; I think someone was trying to download a block of tiles and overwhelmed my server. Appears to be working fine now; if you're still having problems, please let me know directly at so I can investigate further.

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  4. What's your data source for fire history just out of curiosity?