Map Grids ( Graticules )

[Clay Diggins]

We've been considering some additions to the map tools on Land Matters and would like user's feedback.

Land area locations in the U.S. are typically described by their legal land description (PLSS). This is the only system that has been physically surveyed and has actual physical markers on the ground. That's why it's the system for legally describing land parcels.

All the Land Matters maps have the PLSS included as a possible display item but a lot of people (military) have been trained to use a grid to describe actual ground locations. Graticules are very much like grids but they have the advantage of following the earth's curvature, unlike grid maps. Digital graticules are capable of increasing in resolution as you zoom in to an area. These are advantages of a graticule but the use of a graticule is just like using a grid.

It's possible to use both the PLSS and a graticule when mapping so we thought we would see if some people would like the option of using a grid type mapping system. To that end I have included graticule layers on our historic places and ghost towns map to let folks try out this system and see if they would like these layers included on other Land Matters maps.

If you have an interest give it a try at the Historic Places Map. You can read more about grids, graticules and their uses on our New Projects page.

Let us know if you would like this feature added to the maps. It's a bunch of work to make those changes so we'll have to see some demand before we add these in.

Barry

[delnorter]

Wow, another ambitious undertaking. From your list of ongoing improvements to your mapping, I would like to see the land patents and wilderness layers implemented first Barry.

Great mapping library / repository,

Mike

[Clay Diggins]

On 1/29/2019 at 8:46 PM, delnorter said:

Wow, another ambitious undertaking. From your list of ongoing improvements to your mapping, I would like to see the land patents and wilderness layers implemented first Barry.

Great mapping library / repository,

Mike

Thanks for the feedback Mike. ?

We've already mapped the wilderness areas on the Land Status Maps. There is a single wilderness map for the entire United States as well as individual mapping on each of the State specific Land Status maps.

The Patents mapping is a work in progress. 4 years now! With more than 6 million patents to map it's been a real challenge. We do have a few State wide patent maps that are working in house but we'd like to tune those a lot more before we go public. Each map has links to a copy of each patent grant as well as the survey plat when available. If you would like I can send you a link privately to a sample patent map so you can see how we are progressing and get your feedback. Just PM me if that's something you would like to comment on, your ideas on this would be of value to us.

You can see mineral patent mapping with direct grant downloading and links to the Serial Register entries on the California, Colorado and Arizona Mining Claims Maps. The mineral patent boundaries can usually be seen by turning on the "Special Surveys" and "PLSS Second Division" map layers as well.

We could include mineral patents on the other mining claim maps but like our many other projects we rely on public input to guide what gets priority. So far there have been no requests to continue with mineral patent mapping so it's got a low priority.

Barry

 

[Clay Diggins]

On 1/29/2019 at 9:30 PM, davsgold said:

G'day Clay Diggins

I like this system,  Universal Transverse Mercator (UTM, is it anything like you describe in your post, in Australia I just set all our GPS equipment to this system, and use the same in Google Earth and Oziexplorer as well, and for checking the leases in Western Australia using "Tengraph" which can also be set to the UTM system.

I like it for the simple reason you have 2 sets of numbers, Easting and Northing, and a of course you need to know what Zone, which is mostly automatic on the GPS as it knows what zone/region you are in.

cheers dave 

 

Hi Dave,

I'd written a more involved reply as to why UTM is a good system for small local mapping but fails in a larger map but I lost the whole kit and caboodle when I went for a glass of water. Being as how I type with one finger and I still have to work for a living I'm not able to recreate the whole post again. I'll leave you with a short explanation and a link to a really cool animation that helps explain the why UTM is not a good choice for this grids and graticules over a large area..

From The Nature of Geographic Information

Quote

One disadvantage of the UTM system is that multiple coordinate systems must be used to account for large entities. The lower 48 United States, for instance, is spread across ten UTM zones. The fact that there are many narrow UTM zones can lead to confusion. For example, the city of Philadelphia, Pennsylvania is east of the city of Pittsburgh. If you compare the Eastings of centroids representing the two cities, however, Philadelphia's Easting (about 486,000 meters) is less than Pittsburgh's (about 586,000 meters). Why? Because although the cities are both located in the U.S. state of Pennsylvania, they are situated in two different UTM zones. As it happens, Philadelphia is closer to the origin of its Zone 18 than Pittsburgh is to the origin of its Zone 17. If you were to plot the points representing the two cities on a map, ignoring the fact that the two zones are two distinct coordinate systems, Philadelphia would appear to the west of Pittsburgh.

Yeah UTM is actually 60 different map projections that can be treated as one as long as you are working within one UTM zone. Essentially besides the abnormal distortion and lack of repeatable measuring accuracy UTM still depends on four factors in it's description of a single point - the UTM Zone number, North or South of the Equator, the Easting and the Northing. Just as many factors as Lat/Long.

There is a lot more to this whole thing of map projections and which one is best but in the end each map projection has it's own strengths and weaknesses. I myself use UTM on some of my small local map projects when that's the best choice for the use intended. We have thousands of different map projections so we can use the right one for the job at hand. Although UTM is a fine projection on a small local level the compromises involved don't make it a good projection for large scale grids and graticules.

Thanks for the input Dave.

Barry