Jump to content
Nugget Shooter Forums

Question of searching longitude /latitude coordinates


Recommended Posts

At times I go on this site https://mrdata.usgs.gov/mrds/map-us.html and look up mines within my area. When you click on any given mine claim the longitude and latitude coordinates are given.  Question I have is why are the coordinates totally off by 1/4 to 1/2 mile from the site itself  when I Search for them on Google Earth?  

Link to post
Share on other sites

Sounds like you're using statute miles when you should be looking at nautical with your device.

  • Thanks 1
Link to post
Share on other sites

After reading the Mindata info on locations I  understand why they are not accurate

Map Location Accuracy: The coordinates listed for many locations are general regional coordinates (not accurate) and should not be relied upon for locating localities (eg with a GPS).

Map Scales: The maps scales shown below may be the scales of the original map data (eg 1:50000 Landranger Maps) and NOT the scale as they may appear on your screen. Not all map scales listed below may be available for every location, in some cases links may default to another scale - there may be only one scale available for some places. Many sites may share same data, but you can choose which you prefer to use.

Link to post
Share on other sites
34 minutes ago, Relichunter2016 said:

At times I go on this site https://mrdata.usgs.gov/mrds/map-us.html and look up mines within my area. When you click on any given mine claim the longitude and latitude coordinates are given.  Question I have is why are the coordinates totally off by 1/4 to 1/2 mile from the site itself  when I Search for them on Google Earth?  

One possibility is the data given on usgs website was taken before accurate longitude and latitude readings became readily available. These days just about any good gps unit will give accurate information. That same data may not have been available when the mine was originally listed.

Link to post
Share on other sites
29 minutes ago, Morlock said:

One possibility is the data given on usgs website was taken before accurate longitude and latitude readings became readily available. These days just about any good gps unit will give accurate information. That same data may not have been available when the mine was originally listed.

I am beginning to think the same, seems like these coordinates on this site are way off by at least a quarter mile if not more. 

Link to post
Share on other sites

It's not the map, scale or anything to do with lat/long problems it's the MRDS data the mine map is created from. In our experience the MRDS is off by at least a quarter mile in about 70% of the displayed mines. Not in any particular direction just very inaccurate locations.

The MRDS is made up from two very old paper datasets. The MAS and the MLS. There are about 20% - 30% duplicates in any given area because both MAS and MILS locations were created for each mine feature. With a large overlap in the two old paper datasets it's common to have the same mine displayed twice in two different locations.

The Lat/Long you see as the location on MRDS was in most cases put into the database by someone who had never been to the location guessing from the written location description. There is no way to fix the MRDS but the USGS has been working on another system that might recreate this information in a more accurate form. The idea is to match up the mining features from the old topo maps with the data in the MRDS. The advantage is that the topo locations are generally accurate to within about 50 foot because each mining feature on the topo was located on the ground before being added to the map.

It's possible to locate a mine on the topo map and by reading the surrounding MRDS mine descriptions you can usually figure out which of the topo map features show where the mine is actually located. I don't know when the USGS will be able to complete this huge project but they are well along on digitizing the topo map mining features.

Land Matters kind of jumped ahead of the USGS by providing you with both the Topo Mineral Features as well as the MRDS mines mapping on their Mining Claims Maps. In my experience having the two sets of features on one map usually makes short work of finding the actual location of a mine in the MRDS system.

Just find the mine you are looking for with the MRDS map layer selected and look around that location with the Topo Mineral Features selected for the nearest mine feature that matches. You can display both features at once so no flipping back and forth is needed. Give it a try and I think you will be able to sort out those bad MRDS locations pretty quick.

  • Like 2
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...