A Control Field Δ (or Field Δ for short) is created in-Scanner when three Portals controlled by the same Faction are linked together in a triangle and are used to collect the primary scoring metric, Mind Units (MU). They are shown on the map as Control Fields Δ of Enlightened 
or Resistance 
in accordance with the Faction that controls them.
The creation and maintenance of Control Fields Δ provides the controlling Faction with additional score, while the other Faction benefits from disrupting them. Control Fields Δ can be disrupted by attacking and capturing one or more of the Portals whose Links form them.
Control Fields Δ can range from very small (a few hundred square meters) to very large (conceivably stretching over hundreds of kilometers), depending on the level of the Portals involved and Agents' willingness to travel between Portals to link them. Fully upgraded Portals (those with eight Level 8 Resonators 
) can link to Portals hundreds of kilometers away if an Agent has the Portal Keys 
for the (remote) target Portal, allowing large areas of land to be "controlled" quickly.
Creating Control Fields Δ is a very efficient method of gaining Access Points (AP) for leveling up, as the Agent receives 313 AP for each Link created and an additional 1 250 AP if a Field Δ results from the creation of the new Link (or 2 500 AP in case two Control Fields Δ are created simultaneously by a single Link).
Creating Control Fields Δ[]
To create a Control Field Δ, three Portals must be linked in a triangle. The three Portals where the Links forming the Control Field Δ originate from are often called Anchors. Portals inside the Field Δ can only be linked to from the anchor Portals unless the distance from the Portal to the target Portal does not exceed 500m. Control Fields Δ can overlap (see: Advanced Control Field Building) as long as none of the Links cross. The three anchor Portals whose Links form the Field Δ are always considered outside of the Control Field Δ, but may be covered by another Field Δ later.
MU score formula is not known, however, it is known that it is proportional to the surface area of the Field Δ, and there is a correlation with the population density under the Control Field Δ, and the amount of population immediately surrounding the anchor Portals.
Medals[]
The following Medals can be earned by creating Control Fields Δ:
| Bronze | Silver | Gold | Platinum | Onyx |
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|
|
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| 100 | 500 | 2 000 | 10 000 | 40 000 |
Advanced Control Field Δ Building[]
Layering Control Fields Δ is the most efficient way to gain MU. Setting up certain Links that might end up in a Field Δ is essential to creating layered Control Field Δ. No Link can create more than two Control Fields Δ; one on either side.
Principles[]
For instance, if the AB-Link is made last in this image, Δ ABE and Δ ABD will become Control Fields Δ, but Δ ABC will not become a Control Field Δ. The inner most Control Field Δ must be created first. If Δ ABC is the first Control Field Δ then it will become two layers deep when Δ ABD is created. When CD-Link is created after Δ ABD, Δ BCD and Δ ACD will be formed, creating two layers all over Δ ABD. Δ ABE can be created anytime.
Double Anchor Pyramids[]
Double Anchor Pyramids Control Field Δ are a popular way to field boulevard Portals in a straight line. This example shows one way to field a three point top pyramid. The DE-Link is created first so that the Agent no longer has to move to those Portals. The Δ ABC outer most Control Field Δ is then created. Δ BCD is created next by pointing the outside Portals to the inside. AD-Link is created next to get the two Control Fields Δ. Finally, Δ BCE is created to get three more Control Fields Δ.
For pyramids with more than 3 top points, first collect from each of the two base points of the pyramid enough Portal Keys to connect to every top point. At the line of Portals link them from closest to the base to the farthest. Starting at the second Control Field Δ, link each Portal to the top of the previous Control Field Δ. If the Agent had up to eight Portal Keys for the line of Portals when at the base, they can all be connected while the Agent is there so long as they are all connected to only one of the base points. This can greatly decrease the time to field.
In the event there are Portals inside the Control Fields Δ for which the Agent has Portal Key , they can be linked to the base right away, then linked to the Control Field Δ just before them. After they are covered by a Control Field Δ, and before another Control Field Δ is laid, they can be linked to the next top point for a double Control Field Δ creating a clover Control Field Δ (see below).
Single Anchor Pyramids[]
These pyramids take significant time and Portal Key inventory. This is better done when the anchor can be well secured (has limited access) or a lot of Agents will be protecting it and fielding the other Portals. Again, it is built smallest to largest, but the base is being extended out instead of the tip. Each base is connected to the previous and then linked across to create double Control Fields Δ.
Clover[]
A single Portal with three or more Control Field Δ covering all 360 degrees around it.
Ingress Details on Field Maximization
Advanced Field Creation
Other Multi-layered Fielding[]
Dai T's lessons for multi-layered fielding cover many setups, including ways to profit from a long row of 8/16/24 Portals by only visiting each Portal three times (without getting as many Portal Keys from the base Portals).
Field Art[]
A lot of Agents enjoy creating Field art with the Control Fields Δ. They are often done for special events and cross-faction.