Mgrs grid finder

Mgrs grid finder DEFAULT

Screenshots

Description

This application is GPS and coordinate systems helper especially for military personnel.

It is also a complete helper for mountaineering, trekking and hiking, cross running, scouting, hunting, fishing, geocaching, off-road navigation and all other outdoor activities and sports.

With satellite navigation systems such as GPS, GALILEO and GLONASS (GNSS) supported by your device and your sensors, you can see your most accurate position on different map layers.

*Import/Export KML

Version 3.3.7

Ratings and Reviews

4.7 out of 5

1.2K Ratings

Compass

I absolutely love this app. However, I wish there was a way to calibrate the compass, it is not accurate. If I were to follow it, it would take me 120 degrees in the wrong direction.

Hi. Thanks for feedback. Can you tell your phone model to us? We will check the problem.

MGRS Pro

I want to buy the pro version, but I’m not sure how much it is. The app doesn’t state it anywhere. Can you help?

Camping

This app is perfect for letting your 4 wheel drive friends find you for an outdoor get together

The developer, Vahid Cataltas, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Used to Track You

The following data may be used to track you across apps and websites owned by other companies:

Data Linked to You

The following data may be collected and linked to your identity:

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Information

Seller
Vahid Cataltas

Size
75.5 MB

Category
Navigation

Compatibility
iPhone
Requires iOS 11.0 or later.
iPad
Requires iPadOS 11.0 or later.
iPod touch
Requires iOS 11.0 or later.
Languages

English, Turkish

Age Rating
4+

Location
This app may use your location even when it isn’t open, which can decrease battery life.

Copyright
© 2017 - 2021 DAKIKTECH

Price
Free

In-App Purchases

  1. Pro Features$17.99

Supports

  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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Sours: https://apps.apple.com/us/app/mgrs-utm-map/id1439891984

MGRS grids

Components

Grids are composed of combinations of the following components:

The 100,000m Grid Zone Label and Grid Zone Designation Label components are not available for coordinate systems other than UTM.

These components are managed on the Components tab Components in the Format Map Grid pane.

Due to the dynamic nature of grids, there are limitations on modifying components. If you cannot achieve the necessary grid configuration by modifying the component properties, consider converting the grid to graphics and modifying the resulting graphics.

To add a component, click the Add button Add and choose from the list of available components. To remove a component, select it in the list and click RemoveDelete. Use the arrow buttons Move Item UpMove Item Down to move selected components up or down in the drawing order.

Select a component in the Components list to modify its properties.

Gridlines

Gridlines are the lines crossing over the map that delineate the x- and y-values of the coordinate system. Set the X and Y intervals to determine where the gridlines are drawn. Check Sync Values to keep the x- and y-values the same when one is modified.

Click the Symbol to modify the appearance of the gridlines.

Ticks

Ticks are linear marks at the edges of a grid. Multiple ticks of different styles and intervals can be used to delineate major and minor divisions on your grid. Set the X and Y intervals to determine where the ticks are drawn. Check Sync Values to keep the x and y tick values the same when one is modified.

Click the Symbol to modify the tick's appearance. Set the position of the ticks relative to the map frame by specifying an Offset value.

Under the Visible heading, use the cardinal direction check boxes to specify which ticks are shown. It is important to remember that the cardinal direction boxes refer to the direction the line is drawn, not how the line is labeled. For example, lines drawn north and south are labeled with easting and westing values.

Alternatively, on the Options tab Properties, check Define map grid edges to control the visibility by the cardinal points at each map frame edge. On the Components tab Components, set Edges to Selected. Select one or more map frame edges and use the cardinal direction check boxes to set the visibility for only those edges.

Grids with ticks turned on and off for different edges

Check Show edge visibility indicators to identify the edges with numbered buttons. Select an edge by clicking this button or choosing the number in the pane.

Labels

Labels are the textual x- and y-coordinates at the edges of the grids. Set the X and Y intervals to determine where the labels are drawn. Check Sync Values to keep the x- and y-values the same when one is modified.

Click the Symbol to modify the text symbol of the labels. Set the position of the labels relative to the map frame by specifying an Offset value.

Label text is set using tags in the Format text box. Tags can be used alone or in combination to create labels. See Work with grid label tags for descriptions of the tags along with examples.

Check the Vertical check box for each cardinal point to draw those labels vertically.

Under the Visible heading, use the cardinal direction check boxes to specify which labels are shown. It is important to remember that the cardinal direction boxes refer to the direction the line is drawn, not how the line is labeled. For example, lines drawn north and south are labeled with easting and westing values.

Alternatively, on the Options tab Properties, check Define map grid edges to control the visibility by cardinal points for each map frame edge. On the Components tab Components, set Edges to Selected. Select one or more map frame edges and use the cardinal direction check boxes to set the visibility for only those edges.

Grids with labels turned on and off for different edges

Check Show edge visibility indicators to identify the edges with numbered buttons. Select an edge by clicking this button or choosing the number in the pane.

Corner Labels

Corner labels are the textual coordinates at the vertices of the map frame. Map frames in the shape of an ellipse, a circle, or a lasso have only one corner label. Each corner label represents a point and has two labels: one for the east-west direction and one for the north-south direction.

If you check Define map grid edges and change the Minimum length value to reduce or increase the number of edges or corners, those changes will be reflected in the number of corner labels.

The X and Y intervals determine the coordinate in the label. By default, the interval is set to 0,0, meaning that the coordinate of the map frame corner is shown. Increasing the interval places the labels offset from the corner at that distance. For corner labels with an interval greater than 0,0, if the angle of the gridlines is nonperpendicular or nonparallel to the edge of the map frame, there may be multiple corner labels per corner. Check Sync Values to keep the x- and y-values the same when one is modified.

To change the appearance of the corner label text, click the Symbol. Set the position of the corner labels relative to the map frame by specifying an Offset value.

Corner label text is set using tags in the Format text box. Tags can be used alone or in combination to create labels. See Work with grid label tags for descriptions of the tags, along with examples.

Corner labels can be turned on or off for each corner of the map frame using the Corner Visibility controls. To see the corners, switch the Corners toggle button to Selected and check Show edge visibility indicators. Numbered buttons appear on each corner of the map frame on the layout. Select a corner by clicking one of these buttons or choosing the corresponding number from the list in the pane.

To turn off the corner label for a single corner, switch the Corners toggle button to Selected. Select the corner to turn off, and uncheck both the North-South and East-West check boxes.

100,000m Grid Zone Labels

100,000m grid zone labels are the two letter designators for each 100,000-meter square in a UTM zone.

Label placement is set by the Positioning control. Use the Corner and Center options to place the labels at the corner of each 100,000-meter square or at the center of the square, respectively. Center positioning will display the coordinates on any map extent. Corner positioning only displays the labels if the corner of the 100,000-meter square is within the map extent.

To change the appearance of the labels, click the Symbol.

Intersection Points

Intersection points are point symbols showing where coordinate lines intersect. You can use intersection points, without gridlines, to create a grid of points on your map.

Set the X and Y intervals to determine where the intersection points are drawn. Check Sync Values to keep the x- and y-values the same when one is modified.

To change the appearance of the intersection points, click the Symbol.

Interior Labels

Interior labels are the textual coordinates within the grid, usually placed on top of gridlines.

Set the X and Y intervals to determine where the interior labels are drawn. Check Sync Values to keep the x- and y-values the same when one is modified.

To change the appearance of the label text, click the Symbol.

Label text is set using tags in the Format text box. Tags can be used alone or in combination to create labels. See Work with grid label tags for descriptions of the tags, along with examples.

The X Gap and Y Gap options set the amount of space between the gridline and the label drawn on top of it. This can be increased or decreased.

There are three options for where labels are shown on the grid: 1/2 1/2, 1/3 1/3, and 1/4 1/4. Each option has different positioning and displays a different number of labels.

Interior Ticks

Interior ticks are linear marks within the grid that show coordinate intervals. They can be displayed on top of, or in place of, gridlines.

There are two sets of intervals for interior ticks. The Grid Interval option specifies the coordinate lines where ticks draw. The Tick Interval option specifies the frequency with which ticks draw along those lines. By default, the intervals are calculated based on scale. To set the intervals manually, on the Options tab Properties, uncheck Automatically adjust. On the Components tab Components, type the X and Y intervals. Check Sync Values to keep the x- and y-values the same when one is modified.

Click Symbol to modify the tick's appearance. Set the position of the ticks relative to the map frame by specifying an Offset value.

Check Show direction from origin to display ticks above, below, left, or right of the gridline, depending on the direction from the grid origin. If this box is not checked, ticks are drawn across the gridline. The grid's origin can be updated on the Options tab Properties.

Grid Zone Designation Labels

Grid zone designation labels are the letter and number combinations unique to each UTM zone. They can be drawn at the vertical and horizontal boundaries of the grid zone.

Text surrounding the grid zone designation label is set using the Format text box. The tag <dyn type="gridzonedesignator"/> specifies the grid zone designator and is added by default. Static text can be added before or after the tag to customize how the grid zone designator is displayed on the grid.

To change the appearance of the grid zone designation text, click the Symbol.

Set how many labels will draw, and their positions using the Vertical and Horizontal groups. Grid zone designation labels can be drawn on vertical UTM boundaries at the top, center, and bottom of the grid. For horizontal UTM boundaries, they can be draw at the left, right, and center of the grid. Check the boxes next to each placement to determine how many labels will draw and where each will be located. These positions are in reference to the grid itself, not to the UTM zone. If the UTM zone is visible in the map extent, the labels can be drawn at any of these positions. Use the X Offset and Y Offset properties to determine how far away from the boundary the labels will draw.

Sours: https://pro.arcgis.com/en/pro-app/latest/help/layouts/mgrs-grids.htm
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MGRS / USNG to Latitude and Longitude

Example:
  12U UA 84323 40791
  12U UA 84 40


Latitude and Longitude to MGRS / USNG

Example:
Latitude 50.00820   Longitude -112.61440

Example:
Latitude 50° 00' 29.52" N   Longitude 112° 36' 51.84" W


United States National Grid (USNG) - Grid Zone Designations (GZD)

United States National Grid (USNG) - Grid Zone Designations (GZD)

USNG Map with 6 x 8 Degree Grid Zone Designators

Click for larger United States National Grid (USNG) Index Map with 6 x 8 Degree Grid Zone Designators

United States National Grid Index Map in PDF

United States National Grid Page at Federal Geographic Committee


Click for a larger 4200 x 2200 World Map with MGRS Grid
World Map with MGRS Grid

(*) Get GPS Location Button

When supported, clicking this button automatically fills in your current Latitude and Longitude.

When not supported, clicking the button does nothing.

The best accuracy (within about 10 meters) is obtained on devices with a built in GPS chip such as smart phones which can directly receive satellite GPS signals.

On computers without a GPS chip, Latitude and Longitude are guesstimated by Google based on your IP address and the known locations of the nearest WIFI access points.


MGRS Batch Converter
Sours: https://legallandconverter.com/p50.html
UTM, MGRS and location for larger scales

Mgrs & Utm Map

This application is GPS and coordinate systems helper especially for military personnel.

It is also a complete helper for mountaineering, trekking and hiking, cross running, scouting, hunting, fishing, geocaching, off-road navigation and all other outdoor activities and sports.

With satellite navigation systems such as GPS, GALILEO and GLONASS (GNSS) supported by your device and your sensors, you can see your most accurate position on different map layers.


Features:

* Easy and Faster
* Compass.
=> Compass on map (on the map that shows your direction)
=> Compass only (shows physical directions)
=> Angular units for compass (degrees ,NATO mil, Soviet Mil, Grad)
* Follow Mode
=> The center of the map follows your location while on the move.
* You can add and removing markers.
* Distance measure. (You can add custom route and calculate total distance)
* Area measure.(You can select an area on the map and calculate the area in square meters)
* You can see the altitude of your location.
* You can find the location according to Degree/Minute/Second , MGRS, UTM or Latitude/Longitude formats.
* Location (Coordinate) format options.
=> MGRS / U.S. National Grid (USNG) (WGS84/NAD83)
=> D°M'S" (WGS84)
=> Latitude/Longitude (WGS84)
=> UTM (WGS84/NAD83)
=> SK42(Gauss Kruger)
* Map type options (Road,Terrain,Satellite,Night Mode,Hybrid)
* You can share location coordinate.
* Distance unit options. (meter and feet).
* KML viewer. (Export and import KML layers).
* GPS track recorder.

Sours: https://play.google.com/

Grid finder mgrs

A Quick Guide to Using MGRS Coordinates

Standing at the center of the marker shown on the map below, a GPS unit set to display position in US National Grid format, would report a location of:

GPS Display MGRS

Let's look at where the various parts of the MGRS position come from on the map.

Map with MGRS position

The map has grid lines spaced every kilometer or 1000 meters. The grid is labeled with UTM coordinate values. But the same grid is used for both MGRS and USNG positions. When using MGRS or USNG the small type numbers to the left of the larger type numbers are replaced by the 100,000m Square ID. The vertical grid lines determine East-West position and the horizontal grid lines determine North-South position.

Look along the bottom edge of the map at the labels for the vertical grid lines.

Grid Labels

The label, 706000m E, reads "seven hundred and six thousand meters East." The label, 707, is an abbreviation for, 707000m E The two grid lines are 1000 meters apart. The horizontal grid lines are labeled in a similar manner.

The 10S is the Grid Zone Designation you are in. The Grid Zone is necessary to make the coordinates unique over the entire globe.

The GJ is the 100,000 meter Square ID. It identifies a unique 100,000m square within the Grid Zone.

The top set of numbers, 06832, represent a measurement of East-West position, within the 100,000 meter square, in meters. It's called an Easting. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the west of the position. The last 3 digits are the distance in meters measured from the western grid line.

The bottom set of numbers, 44683, represent a measurement of North-South position, within the 100,000 meter square, in meters. It's called a Northing. Using a map with a 1000m grid, the first two digits are come from the large type on the label for the grid line to the south of the position. The last 3 digits are the distance in meters measured from the southern grid line.

The MGRS standard states that "To facilitate machine-to-machine communication, an MGRS string is to have no intermediate spaces or punctuation marks and all the letters are to be capitals." I have not strictly followed this part of the standard in these tutorials. The inclusion of spaces to separate the logical parts of the coordinate string has been shown to facilitate the understanding and communication of coordinate strings between humans. I would encourage you to use spaces when writing MGRS coordinate strings, and to pause briefly between logical parts when communicating MGRS coordinate strings verbally.

Truncated position formats for less precise positions

The MGRS format is designed to support measurement precisions of 1m, 10m, 100, 1,000m, and 10,000m. by truncating the grid coordinate values.

10S GJ 06832 44683 - Locates a point within a 1 meter square
10S GJ 0683 4468 - Locates a point within a 10 meter square
10S GJ 068 446 - Locates a point within a 100 meter square
10S GJ 06 44 - Locates a point within a 1,000 meter or 1 kilometer square
10S GJ 0 4 - Locates a point within a 10,000 meter or 10 kilometer square
10S GJ - Locates a point within a 100,000 meter or 100 kilometer square


When all of the coordinates you are working with are localized within the same 100,000 meter square identifier, it is permissible to drop the Grid Zone Designator and the 100,000 meter square id.

06832 44683 - Locates a point within a 1 meter square
0683 4468 - Locates a point within a 10 meter square
068 446 - Locates a point within a 100 meter square
06 44 - Locates a point within a 1,000 meter or 1 kilometer square
0 4 - Locates a point within a 10,000 meter or 10 kilometer square

Note: It is easy to make an mistake using truncated position formats. Slipping a digit left or right results in a very different position. Worse, there is no visual clue that an error has been made, until the coordinate is plotted.

Truncate, don't round

When using less precise representation, it is important to truncate rather than round the Easting and Northing values. The Easting and Northing always refer to the southwest corner of the grid square. The size of square represented by a given coordinate will vary with the coordinate's precision. Truncating ensures the more precise squares will always remain within the less precise squares.

Using various tools to plot and measure MGRS positions on a map

Learn more about...

Map Datums and why they are so important

Locating MGRS grid information on USGS topographic maps

Grid Zone Details

The 100,000 meter square identifier letter pairs

Metric Distance Measurements

The small differences between USNG and MRGS

Some of the history behind the military adoption of UTM and MGRS

More than you probably want to know...

National Geospatial Intelligence Agency Standardization Document, Universal Grids and Grid Reference Systems (101 page pdf)

Sours: https://www.maptools.com/tutorials/mgrs/quick_guide
How to Plot 8 Digit Grid Coordinates


Anyone can use the following 'live' GISsurfer map to help learn about Military Grid Reference Sysytem (MGRS) coordinates. This map with a MGRS grid will work in most browsers on most devices including cell phones.

The map is displayed by GISsurfer which is a general purpose web map based on the Leaflet map API (Application Program Interface). For a description of all the features of GISsurfer that support MGRS coordinates (search, geolocation, etc) and links to videos plus other educational material, please download the USNG and MGRS Coordinates pdf file.

USNG stands for U.S. National Grid. MGRS and USNG are the same except MGRS is often written without spaces. If you know MGRS then you already know USNG.

As you zoom in the grid will become more detailed. Note that different basemaps let you zoom in different amounts. Use the Menu button to toggle the MGRS coordinates grid on/off.

While the map is open you can now display data from *any* public-facing (i.e. no login required) ArcGIS server along with an MGRS grid on top of that data. To get started, click the basemap button (next to the 'Menu' button) then under the 'Overlay' heading, click "Add GIS overlays". In the popup that appears, click 'Help'.

For more information about GISsurfer, please visit the GISsurfer homepage.

Up until the middle of 2018 the map on this page was based on the Google map API (Application Program Interface). But that year Google started charging $$$ for its API use on popular web maps that got a high volumn of hits. As a result, the web maps I produce are now based on the free open-source Leaflet map API.

And if you would like a web app for your smartphone that will display your MGRS/USNG coordinates and the equally important accuracy value, then take a look at FindMeSAR (https://findmesar.com). The "Tips" button has more information about this web app.

View the map full screen

Sours: https://mappingsupport.com/p2/coordinates-mgrs-gissurfer-maps.html

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Military Grid Reference System

The Military Grid Reference System (MGRS)[1] is the geocoordinate standard used by NATO militaries for locating points on Earth. The MGRS is derived from the Universal Transverse Mercator (UTM) grid system and the Universal Polar Stereographic (UPS) grid system, but uses a different labeling convention. The MGRS is used as geocode for the entire Earth.

An example of an MGRS coordinate, or grid reference, would be 4QFJ12345678, which consists of three parts:

  • 4Q (grid zone designator, GZD)
  • FJ (the 100,000-meter square identifier)
  • 12345678 (numerical location; easting is 1234 and northing is 5678, in this case specifying a location with 10 m resolution)

An MGRS grid reference is a point reference system. When the term 'grid square' is used, it can refer to a square with a side length of 10 km (6 mi), 1 km, 100 m (328 ft), 10 m or 1 m, depending on the precision of the coordinates provided. (In some cases, squares adjacent to a Grid Zone Junction (GZJ) are clipped, so polygon is a better descriptor of these areas.) The number of digits in the numerical location must be even: 0, 2, 4, 6, 8 or 10, depending on the desired precision. When changing precision levels, it is important to truncate rather than round the easting and northing values to ensure the more precise polygon will remain within the boundaries of the less precise polygon. Related to this is the primacy of the southwest corner of the polygon being the labeling point for an entire polygon. In instances where the polygon is not a square and has been clipped by a grid zone junction, the polygon keeps the label of the southwest corner as if it had not been clipped.

  • 4Q .....................GZD only, precision level 6° × 8° (in most cases)
  • 4QFJ ...................GZD and 100 km Grid Square ID, precision level 100 km
  • 4QFJ 1 6 ...............precision level 10 km
  • 4QFJ 12 67 .............precision level 1 km
  • 4QFJ 123 678 ...........precision level 100 m
  • 4QFJ 1234 6789 .........precision level 10 m
  • 4QFJ 12345 67890 .......precision level 1 m

Grid zone designation[edit]

UTM zones on an equirectangular world map with irregular zones in red and New York City's zone highlighted

The first part of an MGRS coordinate is the grid-zone designation. The 6° wide UTM zones, numbered 1–60, are intersected by latitude bands that are normally 8° high, lettered C–X (omitting I and O). The northmost latitude band, X, is 12° high. The intersection of a UTM zone and a latitude band is (normally) a 6° × 8° polygon called a grid zone, whose designation in MGRS is formed by the zone number (one or two digits – the number for zones 1 to 9 is just a single digit, according to the example in DMA TM 8358.1, Section 3-2,[1] Figure 7), followed by the latitude band letter (uppercase). This same notation is used in both UTM and MGRS, i.e. the UTM grid reference system; the article on Universal Transverse Mercator shows many maps of these grid zones, including the irregularities for Svalbard and southwest Norway.

As Figure 1 illustrates, Honolulu is in grid zone 4Q.

Figure 1. The origin of the MGRS grid, in the Pacific. Honolulu is in 4QFJ.

100,000-meter square identification[edit]

The second part of an MGRS coordinate is the 100,000-meter square identification. Each UTM zone is divided into 100,000 meter squares, so that their corners have UTM-coordinates that are multiples of 100,000 meters. The identification consists of a column letter (A–Z, omitting I and O) followed by a row letter (A–V, omitting I and O).

Near the equator, the columns of UTM zone 1 have the letters A–H, the columns of UTM zone 2 have the letters J–R (omitting O), and the columns of UTM zone 3 have the letters S–Z. At zone 4, the column letters start over from A, and so on around the world.

For the row letters, there are actually two alternative lettering schemes within MGRS:

  • In the AA scheme,[2] also known as MGRS-New,[3] which is used for WGS84 and some other modern geodetic datums, the letter for the first row – just north of the equator – is A in odd-numbered zones, and F in even-numbered zones, as shown in figure 1. Note that the westmost square in this row, in zone 1, has identification AA.
  • In the alternative AL scheme,[2] also known as MGRS-Old,[3] which is used for some older geodetic datums, the row letters are shifted 10 steps in the alphabet. This means that the letter for the first row is L in odd-numbered zones and R in even-numbered zones. The westmost square in the first row, in zone 1, has identification AL.

If an MGRS coordinate is complete (with both a grid zone designation and a 100,000 meter square identification), and is valid in one lettering scheme, then it is usually invalid in the other scheme, which will have no such 100,000 meter square in the grid zone. (Latitude band X is the exception to this rule.) Therefore, a position reported in a modern datum usually can not be misunderstood as using an old datum, and vice versa – provided the datums use different MGRS lettering schemes.

In the map (figure 1), which uses the AA scheme, we see that Honolulu is in grid zone 4Q, and square FJ. To give the position of Honolulu with 100 km resolution, we write 4QFJ.

Figure 2. The MGRS grid around Hawaii. Honolulu is in the 10 km square that is called 4QFJ15.

Numerical location[edit]

The third part of an MGRS coordinate is the numerical location within a 100,000 meter square, given as n + n digits, where n is 1, 2, 3, 4, or 5. If 5 + 5 digits is used, the first 5 digits give the easting in meters, measured from the left edge of the square, and the last 5 digits give the northing in meters, measured from the bottom edge of the square. The resolution in this case is 1 meter, so the MGRS coordinate would represent a 1-meter square, where the easting and northing are measured to its southwest corner. If a resolution of 10 meters is enough, the final digit of the easting and northing can be dropped, so that only 4 + 4 digits are used, representing a 10-meter square. If a 100-meter resolution is enough, 3 + 3 digits suffice; if a 1 km resolution is enough, 2 + 2 digits suffice; if 10 km resolution is enough, 1 + 1 digits suffice. 10 meter resolution (4 + 4 digits) is sufficient for many purposes, and is the NATO standard for specifying coordinates.

If we zoom in on Hawaii (figure 2), we see that the square that contains Honolulu, if we use 10 km resolution, would be written 4QFJ15.

If the grid zone or 100,000-meter square are clear from context, they can be dropped, and only the numerical location is specified. For example:

  • If every position being located is within the same grid zone, only the 100,000-meter square and numerical location are specified.
  • If every position being located is within the same grid zone and 100,000-meter square, only the numerical location is specified.
  • However, even if every position being located is within a small area, but the area overlaps multiple 100,000-meter squares or grid zones, the entire grid reference is required.

One always reads map coordinates from west to east first (easting), then from south to north (northing). Common mnemonics include "in the house, up the stairs", "left-to-right, bottom-to-top" and "Read Right Up".

Truncate, don't round[edit]

As mentioned above, when converting UTM coordinates to an MGRS grid reference, or when abbreviating an MGRS grid reference to lower precision, one should truncate the coordinates, not round. This has been controversial in the past, since the oldest specification, TM8358.1,[1] used rounding, as did GEOTRANS[4] before version 3.0. However, truncation is used in GEOTRANS since version 3.0, and in NGA Military Map Reading 201[3] (page 5) and in the US Army Field Manual 3-25.26.[5] The civilian version of MGRS, USNG, also uses truncation.[6]

Squares that cross a latitude band boundary[edit]

The boundaries of the latitude bands are parallel circles (dashed black lines in figure 1), which do not coincide with the boundaries of the 100,000-meter squares (blue lines in figure 1). For example, at the boundary between grid zones 1P and 1Q, we find a 100,000-meter square BT, of which about two thirds is south of latitude 16° and therefore in grid zone 1P, while one third is north of 16° and therefore in 1Q. So, an MGRS grid reference for a position in BT should begin with 1PBT in the south part of BT, and with 1QBT in the north part of BT. At least, this is possible if the precision of the grid reference is enough to place the denoted area completely inside either 1P or 1Q.

But an MGRS grid reference can denote an area that crosses a latitude band boundary. For example, when describing the entire square BT, should it be called 1PBT or 1QBT? Or when describing the 1000-meter square BT8569, should it be called 1PBT8569 or 1QBT8569? In these cases, software that interprets an MGRS grid reference should accept both of the possible latitude band letters. A practical motivation was given in the release notes for GEOTRANS,[4] Release 2.0.2, 1999:

The MGRS module was changed to make the final latitude check on MGRS to UTM conversions sensitive to the precision of the input MGRS coordinate string. The lower the input precision, the more "slop" is allowed in the final check on the latitude zone letter. This is to handle an issue raised by some F-16 pilots, who truncate MGRS strings that they receive from the Army. This truncation can put them on the wrong side of a latitude zone boundary, causing the truncated MGRS string to be considered invalid. The correction causes truncated strings to be considered valid if any part of the square which they denote lies within the latitude zone specified by the third letter of the string.

Polar regions[edit]

Figure 3. The MGRS grid around the South Pole.
Figure 4. The MGRS grid around the North Pole.

In the polar regions, a different convention is used.[7] South of 80°S, UPS South (Universal Polar Stereographic) is used instead of a UTM projection. The west half-circle forms a grid zone with designation A; the east half-circle forms one with designation B; see figure 3. North of 84°N, UPS North is used, and the west half-circle is Y, the east one is Z; see figure 4. Since the letters A, B, Y, and Z are not used for any latitude bands of UTM, their presence in an MGRS coordinate, with the omission of a zone number, indicates that the coordinates are in the UPS system.

The lettering scheme for 100,000 m squares is slightly different in the polar regions. The column letters use a more restricted alphabet, going from A to Z but omitting D, E, I, M, N, O, V, W; the columns are arranged so that the rightmost column in grid zone A and Y has column letter Z, and the next column in grid zone B or Z starts over with column letter A. The row letters go from A to Z, omitting I and O. The restricted column alphabet for UPS ensures that no UPS square will be adjacent to a UTM square with the same identification.

In the polar regions, there is only one version of the lettering scheme.[7]

See also[edit]

There are other geographic naming systems of this alphanumeric kind:

References[edit]

  1. ^ abcDMA Technical Manual 8358.1, Chapter 3. Datums, Ellipsoids, Grids, and Grid Reference Systems
  2. ^ abNGA Guidance for the Military Grid Reference System (MGRS).
  3. ^ abcMilitary Map Reading 201, published by NGA
  4. ^ abGEOTRANS Geographic Translator software and source code from the US National Geospatial-Intelligence Agency.
  5. ^Map Reading and Land Navigation, U.S. Army Field Manual No. 3-25.26 (see section 4-6).
  6. ^J. Anthony Cavell, USNG: Getting it right the first time. The American Surveyor, June 2005.
  7. ^ abDMA Technical Manual 8358.1, Appendix B. Datums, Ellipsoids, Grids, and Grid Reference Systems.

External links[edit]

Sours: https://en.wikipedia.org/wiki/Military_Grid_Reference_System


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