Google Earth Pro Easting Northing

[Violette Ransone]

HiI am working with google maps for the first time...I am getting lattitude and longitude but I want them to be converted to northing and easting using javascript and I can't find any approch for it...

You can use easting and northings to plot points on a map. You can also add any custom map services you like (WMS and TMS). I am presuming these points are for the British National Grid coordinate system

Then go into the positioning tab, scroll down and select the option to use coordinate columns, then set the column for your X and Y i.e. easting and northing. Note it may apply an aggregation by default to your columns such as sum or average, so you can click on the arrow beside the column name and set this to none if you don't want these to be aggregated.

With that your points should appear on the map. If they don't, its likely a coordinate system mismatch somewhere.Note that you can also set the coordinate system of the parent map overall. You do this from the map chart properties->appearance tab. You can mix and macth different coordinate columns. For instance use web mercator as your base map coordinate system and for WMS/TMS services, then plot points using British national grid on this.

If the data frame's coordinate system is set to the same coordinate system of your easting/northing values, you can set the units of the Go To XY tool to the same unit (aka meters or feet) and search that way.

Below is a screen grab of ArcMap 10.3 (development, but it's the same in 10.2.x). I set the data frame to use NAD 1927 BLM zone 11N which uses US survey feet. When I open the Go To XY Tool and select the pulldown on the right side, the first unit listed is that of the data frame's coordinate system. If the data frame was using a UTM instead, it would be meters instead.

I was given a csv file and told to convert it to a feature layer. The data is supposedly in State Plane coordinates, NAD 83, Florida North. When I plot this out in ArcMap it ends up being about 182 miles northwest of where it should be. What am I doing wrong? Here's my workflow:

I set the X column to be field 2 and the Y column was field 3 (also I was told the elevation was in field 4 so for a couple of attempts I used that and then discarded it). According to google, I'm about 3386 km from the equator. Should I be confident in using State Plane (ft)?

Hopefully someone in your area will chime in with the correct 'State Plane Whatever' designation. It is like UTM data, there are 120 positions on earth with the same easting and northing, making the numbers useless unless you know the utm zone and whether it is north or south of the equator.

Do you think the error is arising when I project it? Am I doing the actual add data and xy conversion correctly? No, I must not be because the event layer is off . Can I use calculate geometry to fix it?

The numbers are right for somewhere.. I don't understand how you got pairs of coordinates without a spatial reference for them. Did they come from a gps or something? is the csv the result of projecting some data and exporting it?.

Once you create the event layer, (in an empty dataframe... no basemap, nothing), then save it as featureclass/shapefile and immediately use the Define Projection tool in Arctoolbox, to 'tell it what it is' in terms of coordinates. Define the coordinate system of the dataframe using the same projection/coordinate system. If you then add a featureclass that you are absolutely sure about, regardless of its coordinate system, it will project to what you defined previously. If it was the correct definition, then stuff will line up. If not, then the coordinate system/projection was wrong.

This data was given to me by our Engineering Dept - they have a worker who does survey GPS - I've never seen his unit or gotten data from him before. When I asked, all he could tell me was 'state plane'. I sort of took a guess that the rest of his settings would be similar to what other depts here use...hopefully!

When the first standardized coordinate systems were created during the 20th century, such as the Universal Transverse Mercator, State Plane Coordinate System, and British National Grid, they were commonly called grid systems; the term is still common in some domains such as the military that encode coordinates as alphanumeric grid references. However, the term projected coordinate system has recently become predominant to clearly differentiate it from other types of spatial reference system. The term is used in international standards such as the EPSG and ISO 19111 (also published by the Open Geospatial Consortium as Abstract Specification 2), and in most geographic information system software.[3][2]

The map projection and the Geographic coordinate system (GCS, latitude and longitude) date to the Hellenistic period, proliferating during the Enlightenment Era of the 18th century. However, their use as the basis for specifying precise locations, rather than latitude and longitude, is a 20th century innovation.

Among the earliest was the State Plane Coordinate System (SPCS), which was developed in the United States during the 1930s for surveying and engineering, because calculations such as distance are much simpler in a Cartesian coordinate system than the three-dimensional trigonometry of GCS. In the United Kingdom, the first version of the British National Grid was released in 1938, based on earlier experiments during World War I by the Army and the Ordnance Survey.[4]

During World War II, modern warfare practices required soldiers to quickly and accurately measure and report their location, leading to the printing of grids on maps by the U.S. Army Map Service (AMS) and other combatants.[5] Initially, each theater of war was mapped in a custom projection with its own grid and coding system, but this resulted in confusion. This led to the development of the Universal Transverse Mercator coordinate system, possibly adopted from a system originally developed by the German Wehrmacht.[6] To facilitate unambiguous reporting, the alphanumeric Military Grid Reference System (MGRS) was then created as an encoding scheme for UTM coordinates to make them easier to communicate.[5]

After the War, UTM gradually gained users, especially in the scientific community. Because UTM zones do not align with political boundaries, several countries followed the United Kingdom in creating their own national or regional grid systems based on custom projections. The use and invention of such systems especially proliferated during the 1980s with the emergence of geographic information systems. GIS requires locations to be specified as precise coordinates and performs numerous calculations on them, making cartesian geometry preferable to spherical trigonometry when computing horsepower was at a premium. In recent years, the rise of global GIS datasets and satellite navigation, along with an abundance of processing speed in personal computers, have led to a resurgence in the use of GCS. That said, projected coordinate systems are still very common in the GIS data stored in the Spatial Data Infrastructures (SDI) of local areas, such as cities, counties, states and provinces, and small countries.

Because the purpose of any coordinate system is to accurately and unambiguously measure, communicate, and perform calculations on locations, it must be defined precisely. The EPSG Geodetic Parameter Dataset is the most common mechanism for publishing such definitions in a machine-readable form, and forms the basis for many GIS and other location-aware software programs.[3] A projected SRS specification consists of three parts:

To establish the position of a geographic location on a map, a map projection is used to convert geodetic coordinates to plane coordinates on a map; it projects the datum ellipsoidal coordinates and height onto a flat surface of a map. The datum, along with a map projection applied to a grid of reference locations, establishes a grid system for plotting locations. Conformal projections are generally preferred. Common map projections include the transverse mercator (used in Universal Transverse Mercator, the British National Grid, the State Plane Coordinate System for some states), Lambert Conformal Conic (some states in the SPCS), and Mercator (Swiss coordinate system).

Every map projection has a natural origin, e.g., at which the ellipsoid and flat map surfaces coincide, at which point the projection formulas generate a coordinate of (0,0).[7] To ensure that the northing and easting coordinates on a map are not negative (thus making measurement, communication, and computation easier), map projections may set up a false origin, specified in terms of false northing and false easting values, that offset the true origin. For example, in UTM, the origin of each northern zone is a point on the equator 500km west of the central meridian of the zone (the edge of the zone itself is just under 400km to the west). This has the desirable effect of making all coordinates within the zone positive values, being east and north of the origin. Because of this, they are often referred to as the easting and northing.

Grid north (GN) is a navigational term referring to the direction northwards along the grid lines of a map projection. It is contrasted with true north (the direction of the North Pole) and magnetic north (the direction in which a compass needle points). Many topographic maps, including those of the United States Geological Survey and Great Britain's Ordnance Survey, indicate the difference between grid north, true north, and magnetic north.[8]

The grid lines on Ordnance Survey maps divide the UK into one-kilometre squares, east of an imaginary zero point in the Atlantic Ocean, west of Cornwall. The grid lines point to a Grid North, varying slightly from True North. This variation is zero on the central meridian (north-south line) of the map, which is at two degrees West of the Prime Meridian, and greatest at the map edges. The difference between grid north and true north is very small and can be ignored for most navigation purposes. The difference exists because the correspondence between a flat map and the round Earth is necessarily imperfect.

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