Command and Control (C2) Tactical Symbols, as specified in Mil-STD-2525C, represent Units, Equipment, or Installations. They present information that can be pinpointed in one location at a particular point in time. These symbols are composed of frames, fills, icons, and text. The size and shape of a symbol are fixed and remain constant, regardless of the scale of the background projection, unless changed by the operator.
Given the requirements of the standard, how do we represent them in ArcGIS? Tactical Symbols are created in ArcGIS as Unit, Equipment, and Installation (UEI) Features. The UEI Features are stored as point features in a geodatabase. UEI Features are drawn with marker symbols, which are composed of one or more symbol layers that show the frames and fills, with additional symbol layers that provide information about each symbol’s identity, battle dimension, status, and mission.
Composition of tactical symbols
In Mil-STD-2525C terms, a fully displayed tactical symbol is composed of a frame, fill, and icon. It may include text and/or graphic modifiers that provide additional information. The frame attributes (i.e., standard identity, battle dimension, and status) determine the type of frame for a given symbol. Fill color is a redundant indication of the symbol’s standard identity, with red representing enemy and blue representing friendly.
The number of possible combinations of the various Tactical Symbol components is in the millions. Rather than attempting to create a unique symbol for each of these, we’ve stored the components used to draw a UEI Feature as individual marker symbols in style files. These style files are installed with ArcGIS, so they’re available in the Symbol Property Editor and Symbol Selector dialog boxes when you need to define a new UEI Feature. You can combine these marker symbols in multiple symbol layers to properly represent a given UEI Feature.
So, how would you go about doing that? First, you’d decide in which layer to create the new UEI Feature. Layer packages make it easy to generate the layers that you need. See the links here to download layer packages.
A new Friendly Mechanized Infantry unit feature would go in the Friendly Units layer.
Next, you’d change the symbol for the new type of unit.
Next, you’d search for the right base symbol.
To show that the unit is wheeled, you’d add a symbol layer to represent that graphic modifier.
You’d search for the appropriate modifier in the Symbol Selector, much the same way you found the initial symbol.
If necessary, you could use the controls on the Symbol Property Editor to adjust the placement of the new symbol layer.
For all UEI symbols there exists a base symbol in one of the styles which contains the frame and icon referenced by the Symbol ID code. Identity, Status, and symbol modifiers can be added to the symbol as additional layers to differentiate it. For most UEI symbols a feature template may not exist. In these cases the feature template needs to be added to the layer to which the symbol belongs.
Task Force, Headquarters, and Echelon graphic modifiers are examples of symbol layers that would frequently be added to a base symbol as part of defining a new UEI feature template. Unit symbols consist of a frame, a color, branch or functional symbols, and text or graphic symbol modifiers.
In the diagram below, the callouts indicate the required positions for the graphic components of Tactical Symbols (as defined by the 2525-C standard). Many other text modifiers exist as well, but they’ll be covered in another post.
Unit symbol graphic components
|Symbol Icon||The innermost part of a symbol that represents a warfighting object.|
|Echelon||A graphic modifier in a unit symbol that identifies command level.|
|Task Force||A graphic modifier that identifies a unit or SO symbol as a task force.|
|Frame Shape Modifier||A graphic modifier that displays standard identity, battle dimension, or exercise amplifying descriptors of an object.|
|Direction of Movement Indicator||A graphic modifier for units and equipment that identifies the direction of movement or intended movement of an object.|
|Mobility Indicator||A graphic modifier for equipment that depicts the mobility of an object.|
|Headquarters Staff Indicator/Offset Location Indicator||Headquarters staff indicator: A graphic modifier for units, equipment, and installations that identifies a unit as a headquarters. Or: Offset location indicator: A graphic modifier for units, equipment, and installations used when placing an object away from its actual location.|
|Feint/Dummy Indicator||Feint or dummy indicator: A graphic modifier for units, equipment, and installations that identifies an offensive or defensive unit intended to draw the enemy’s attention away from the area of the main attack.|
|Installation||Installation: A graphic modifier for units, equipment, and installations used to show that a particular symbol denotes an installation.|
|Auxiliary Equipment Indicator||A graphic modifier for equipment that indicates the presence of a towed sonar array.|
|Operational Condition||An optional graphic modifier for equipment or installations that indicates operational condition or capacity.|
|Engagement Bar||A graphic amplifier placed immediately atop the symbol. May denote, 1) local/remote status; 2) engagement status; and 3) weapon type.|
The ArcGIS style files for Military Features contain symbols that combine the frame and color, as well as many branch or functional symbols. They also contain additional symbols for the various graphic modifiers. The text modifiers are added in a separate process, as they are labels based on individual feature attributes; the workflow for adding text modifiers will be covered in another post.
Status modifiers and amplifying descriptors
In Mil-STD-2525C terms, the status and details of a tactical symbol can be conveyed using various frame patterns or additional graphic elements. A dashed frame indicates Pending, Assumed, or Suspected status.
These graphic modifiers can be applied to UEI features by adding layers with corresponding marker symbols to the base symbol.
When adding symbols to a base, be aware that the symbols draw in order from the bottom to the top of the stack of symbol layers.
Exercise, Feint, and Dummy modifiers
A symbol can be modified by adding a symbol layer to indicate that a given UEI Feature is part of an exercise.
The same process would be used to indicate that a unit is a Feint, or that a piece of equipment is a Dummy. Add a new layer to the Unit symbol, and search for “Exercise.” Choose an appropriate exercise modifier and click OK.
Operational condition modifiers
Equipment symbols can be given an Operational Condition modifier to indicate the status of the equipment. Add a new layer to the equipment symbol, and search for “operational condition.” Choose an appropriate condition modifier and click OK.
The military symbology styles contain the base symbols and graphic modifiers needed to create the symbols in the MILSTD-2525C standard. ArcGIS also comes other style files and fonts that can be used to construct additional symbols.
Content provided by Bob Booth.
There are many ways of representing locations. One of the most common uses angular latitude and longitude coordinates to specify the location of a point. These Geographic coordinates may be expressed in several different notations, including Decimal Degrees (DD), Degrees Decimal Minutes (DDM), and Degrees Minutes and Seconds (DMS). The formula for converting Degree Minutes and Seconds to Decimal Degrees is discussed in the ArcGIS 10 Help. Another common method is to use a projected coordinate system and X and Y coordinate pairs, that is, two sets of numbers in a planar Cartesian system.
Mosaic datasets were introduced at ArcGIS 10 and are now the best management tool for large sets of raster tiles. If you currently use Military Analyst (MA) DTED and RPF (CADRG and/or CIB) catalogs, we recommend that you move to using mosaic datasets to manage and display these collections of raster data. There are two methods to migrate DTED, CADRG, and CIB data: by reloading the source data into a mosaic dataset; or, by including the MA catalog in a referenced mosaic dataset. Of these, we generally recommend the first method, as it has advantages over referenced catalogs. However, there are cases where you will want to use a referenced catalog, for example, when you are using ArcGIS with an ArcView license. Continue reading
It is common to see data in a geographic coordinate system (GCS). It’s an easily understood, world-wide coordinate system, and many datasets use GCS as part of their spatial reference. However, there are drawbacks to using a geographic coordinate system. One of the most prominent is evident when doing surface analyses over terrain with X,Y coordinates stored in latitude longitude and with elevation values stored in linear units such as meters. This is a problem because degrees of latitude and longitude are angular units measured on a sphere, and meters are linear units measured along a plane. Degrees of longitude are also of variable length, depending upon the latitude, and degrees of longitude represent significantly larger distances than meters over most of the globe (except very close to the poles). Continue reading
Join us at the Esri Federal User Conference in Washington DC this January 19th – 21st. We will be hosting several Defense and Intelligence technical workshops Thursday and Friday of the week, including: Continue reading
The ArcGIS Defense & Intelligence team and Helyx SIS Ltd. have posted the new Patrol Data Capture template for immediate download from Arcgis.com. This desktop application template is designed to help you import and clean patrol tracks from a GPS into ArcGIS. This template assists in separating patrol tracks, removing duplicate points, and detecting and removing error spikes. It includes a sample GPX file and a toolbox with geoprocessing tools to help you work with the imported track data. The template also includes a “Getting Started with the Patrol Data Capture Template” guide to help you set up the template and a “Using the Patrol Data Capture Template” guide to walk you through exercises using the template.
The Imagery basemap template is now available on Arcgis.com! This desktop application template is designed to show you how to view and load CIB data in mosaic datasets. It contains sample data, a map, and a layer file to let you explore how CIB imagery works in mosaic datasets. It also contains a toolbox with a geoprocessing tool to create a mosaic dataset with CIB-specific parameters, and a tool to load CIB data into the mosaic dataset. The quickstart tutorial PDF will walk you through the process of creating the mosaic dataset and loading the sample data.
When you find the shortest flight path between distant points, measure the true length of a flight path with multiple waypoints, or model the effective range of a directional antenna, the geometry you use needs to take the Earth’s curvature into account. Geometry that takes into account the curvature of the Earth is called geodetically-correct geometry, or geodesics, and it can be useful in a variety of Defense and Intelligence tasks.
The new Construct Geodetic tool in ArcMap lets you construct geodetically-correct geometry.
For example, you can use the tool to create a feature showing the shortest flight path between Boston and Cape Town.
The geodesic line between Boston and Cape Town is the shortest distance between the two points on the curved surface of the Earth. A straight line drawn in most projected coordinate systems will diverge from this route.
The tool works in an edit session; first select the feature template you want to edit, select the type of geodetic geometry you want to create (in this case, a Geodesic Line), and click the start and end points (or type them). Click Create to finish the line, or click Add to add another geodesic line segment to the line.
Adding a segment can be useful when you are drawing a flight line with multiple waypoints; each segment will represent the shortest distance (following a geodesic) between each waypoint.
You can also create geodetic circles and ellipses. These may be used to represent range rings for aircraft, weapons, or directional antennas.
Measuring along geodesics
The Measure tool has been enhanced to allow geodetically correct measurements. You can use it to measure the distance between way points in a flight path, or the major axis of a directional antenna range ring.
With snapping enabled you can easily snap to endpoints or vertices of geodetic features for high accuracy geodetic measurements.
Geoprocessing geodetic features
For the Buffer tool to create geodetically-correct buffers, the input geometry must be point or multi-point, the coordinate system must be geographic, and the buffer distance must be given in linear units. For more information on geodesic buffering, see this Help topic.
Storage of geodetic features
Geodetic features are constructed as curves using calculations based on your input parameters, but they are converted to standard feature geometry for storage in the geodatabase when you click the Create button. They’re stored in the geodatabase as a series of densely spaced vertices that closely approximate the geodesic on the GCS spheroid. Since they are densified, rather than parameterized (like arcs and Bezier curves), geodetic features don’t require any special treatment for storage in geodatabases.
If you are designing an ArcSDE geodatabase in which you plan to store geodetic features, we recommend that you avoid using the MS SQL Server 2008 Geography type for feature geometry storage. The SQL Server 2008 Geography type can only store feature geometries that fit in a single hemisphere. This can cause unexpected results when creating or editing geodetic features, and makes the type unsuitable for storing large geodetic features.
Content provided by Dave McGuire
At ArcGIS 10 we’ve moved away from the symbol-centric approach we used in MOLE and built the infrastructure for full-fledged Military Features, stored in databases with appropriate attributes and with full ArcGIS feature-based symbology. Why? Well, for several reasons, but mainly because Military Features provide improved functionality and greater flexibility.
Military Features in geodatabases have attributes better suited to their unique characteristics. For example, Unit features have attributes like echelon and higher formation, while Equipment features have attributes like equipment type, range, and quantity. For all point features we use marker symbols and unique value renderers, which provide the best capability across the ArcGIS technology stack; they work well in desktop, server, and mobile.
In addition to the changes we made within Core ArcGIS to better accommodate military features, we’ve created 13 new style files with the symbols and symbol components needed to symbolize just about any military feature. These symbols are easily modified with standard ArcGIS symbology tools. This flexibility allows warfighters to adapt to changing circumstances and create their own symbols (such as symbols for IEDs); previously, it required a developer to add a new symbol to the system.
What about Symbol Identification Codes?
In our conversations with many military GIS users, we found that the Symbol Identification Codes (SIC) used to identify and construct military symbols with MOLE added an extra layer of complexity to the process. However, they are used by specific systems and databases, and we will support SIC in a couple of ways at ArcGIS 10.
First, we will support ETL of data from others systems where the data is represented using SIC codes. This will be done via a new GP tool called “Append Military Features.” This tool is not part of ArcGIS 10 Pre-Release; it will be released later as an AddIn.
Second, the symbols in the 13 new style files have Symbol ID Code tags, to make it easier for application developers to locate the correct symbols to apply to the layers they create in their solutions. We will provide sample code for doing this.
[Update: We're planning the AddIn and developer sample for the 10.1 timeframe.]
Content provided by Ben Conklin