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Improving Mindat.orgUSGS Historical Topographic Map Explorer

16th Jul 2017 02:47 UTCKevin Conroy Manager

When looking for old mines in the US I've found that the USGS Historical Topographic Map Explorer can be a useful tool. When you go to an area of interest you'll see which USGS maps are available over that spot. Just click on the one that interests you and it will automatically display. To scroll through the dates at the bottom of the screen left click the mouse and hold down, then you can move the date display either left (earlier) or right (more recent).

One drawback is that the search doesn't recognize hardly any mine names, so you usually have to go to a nearby town. Also, as you're typing a name it will offer suggestions. When you see the name that you want, for the best result click on it.

I don't know if Mindat would want to incorporate this viewer into the External Map Resources on the Location Maps page for localities, but for those inclined to do a bit of online exploring I think it's a handy thing to have at your disposal. If you want to see it go to http://historicalmaps.arcgis.com/usgs/

16th Jul 2017 07:11 UTCJolyon Ralph Founder

Thanks, yes I will look into incorporating it

16th Jul 2017 18:43 UTCPaul Brandes 🌟 Manager

I use this quite often as well, although I wish they would make the bedrock geology maps available in this format as I find those much more useful than just the topo maps.

17th Jul 2017 00:30 UTCDoug Schonewald

Paul,

I've integrated the USGS Geo Survey data into my version of Google Earth. Admittedly, it is not perfect and there are instances where I wonder about the accuracy, but it appears that minor exposures of geological formations within a larger formation are considered more of an anomaly than the norm. It works quite well when doing research on the geology of an area and what I hope to locate there in the way of minerals. More detailed papers can be integrated into the use of this feature (and probably should be) to develop a more detailed idea of what minerals might be in a specific locale. I am no professional, but this methodology has worked well for me thus far.

These surveys can be found at the USGS website on a state by state basis. I believe the KLM data is the one you want. Once integrated into Google Earth you can shut them off or turn them on with the click of a button.

17th Jul 2017 00:34 UTCKevin Conroy Manager

Paul, agreed, the USGS has vast holdings that would be great if they made them available in a single viewer. I'm sure they have time/resource/funding constraints on performing the geopositioning and georectifications, especially on some of the older sources that aren't as accurate as the current ones. Oh well, maybe someday...

17th Jul 2017 07:16 UTCJim Gawura

Bedrock geology maps are online. Same starting page. Start with, Map Catalog, Themes-Geology-pull down BEDROCK. Then it's just state and county. 8mb pdf maps available for download.

Cheers

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