Until now it had been common View UTM and geographic coordinates in Google Maps. But usually keeping the datum that Google supports which is WGS84.
What if we want to see in Google Maps, a coordinate of Colombia in MAGNA-SIRGAS, WGS72 or PSAD69?
A coordinate of Spain in ETRF89, Madrid 1870 or even REGCAN 95?
And how about a Mexico coordinate in GRS 1980 or International 1924?
A couple of days ago there is a system that lets you do that, and it's PlexScape WebServices. From Greek friends Creators of Plex.Earth, which integrates data between Google Earth and AutoCAD, which by the way are now doing a tremendous smoke for AutoCAD 2013 that changed the rules of the game.
And this PlexScape service supports no less than 3,000 coordinate systems and 400 Datums, the same ones that support Plex.Earth.
Let's see a test: I will try to explain step by step because honestly the interface is not very intuitive at first glance:
I am now in Bogotá and I am interested in seeing the difference of a coordinate between WGS84 and SIRGAS:
Well, suppose I'm around Top, As shown on the map:
PlexScape Web Services, has now three services: One that is a simple tracking to know the coordinate of a point (Coordinates Tracking), Another to place points on the map and export them to kml / txt (Open Digitizer) And the other is the one we will now use, called Convert Coordinates.
1 Choose the Origin System
For this we select in the tab on the left, the country of our interest. In this case Colombia, and once selected we will indicate WGS84 as Datum of interest.
Between the latitude / longitude tab and Easting / Norting there are different selection options. Interesting that they are nested by country because it would be crazy to look for them among many that the system supports.
2 Place origin point
For this, having visible on the map the area that interests us, we pass the mouse over the lower icon and select «Bring the marker into map«, This will show us the point of interest on the map. Then we drag it to the exact place where we want to locate it. The same can be done with the upper lashes, but it seems more practical to do it from the icon and I will show it throughout the exercise.
If we want to know the coordinate of the point where we have located it, then we go back to the icon and choose «Get coordinates from marker«, With this in our panel the coordinate will be shown.
And if what we want is to place a specific coordinate, then we write it on the panel and passing the mouse over the icon we choose «Set marker to coordinates«, And with this the point will be in the coordinate that interests us.
3 See UTM coordinates
To know the UTM coordinates of this point, we will occupy to indicate the reference zone. If we had doubts we can choose one of them, and with the option «Show boundaries»The area marked in blue appears. Great help, let's remember that Colombia not only falls in the zones 17 North, 18 North and 19 North but also in the same but in the south since the country is crossed by Ecuador with what falls in six zones. Hence, they have adapted their own system of regions that complicate their lives.
In this case, we have chosen UTM Zone 18 N and in effect, we see that there is our point.
3 Move the coordinate of the left panel to the right
So far, what we've seen is how to show a UTM coordinate in Google Maps. But we are interested in seeing that same coordinate in another coordinate system, for the MAGNA-SIRGAS case. First, we use the green arrow to indicate that the same coordinates are moved from the left side to the right side. This is done with a click and what will interest us is that both sides are equal.
Now to activate the right pointer, we do the same: We move the mouse over the icon, and we choose «Bring the marker into map«. If it falls elsewhere, we look for the location again and indicate «Move marker to map center»And to match the coordinate«Set marker to coordinates«.
The signal that everything is fine, is that the blue pointer must be in the same point of the brown pointer if the coordinate system is the same in both. It has some mess, but it works.
4 Know the coordinate WGS84 in SIRGAS
For this we changed from WGS84 to SIRGAS in the right panel. And then we pass the mouse over the icon and say «Get coordinates from marker«, This way we obtain the coordinate of the point that we already have but in the other system. note that in lat / lon the coordinate is just the same, and that is that SIRGAS is based on WGS84.
But if we look at what happens in UTM units, the coordinate in X differs 3 centimeters and the coordinate in Y another centimeter. And this is the reason why it can be said that both systems are equivalent. As we move, this difference changes in millimeters. I clarify that this is according to the parameters that PlexScape Web Services has configured, anything weird has to be reported because it happened to me a couple of times before.
5 Know the coordinate in PSAD
We can choose any other system, and request that you return the coordinate with «Get coordinates from marker«. The pointer should not move, because we are in the same point, what is returning is a coordinate in another system. For this case, in PSAD 1956 this same point has the coordinates X = 604210.66 Y = 512981.6.
Imagine, then, that what we want to see is the same coordinate in the two systems (not the same point), then we copy the coordinate from the left side to the right and then «Set marker to coordinates»And there we have it. The same coordinate below, in both panels, but the blue point drops us displaced 228 meters to the west and 370 meters to the south.
Interesting the PlexScape Web Services tool. In my sole criterion. And another day we will talk about another of its services, of which some of them are paid, including this conversion from a file with many points.