How to modify tile improvents with a building?

[n1ddeh]

For this, I am using a granary. What I want it to do is to if built to add +1 to all farm tiles.
So far I have created an XML file with the following,

Spoiler :

<GameData>
<Buildings>
<Row>
<Type>BUILDING_GRANARY</Type>
<BuildingClass>BUILDINGCLASS_GRANARY</BuildingClass>
<FreeStartEra>ERA_RENAISSANCE</FreeStartEra>
<Cost>100</Cost>
<GoldMaintenance>1</GoldMaintenance>
<PrereqTech>TECH_POTTERY</PrereqTech>
<Help>TXT_KEY_BUILDING_GRANARY_STRATEGY</Help>
<Description>TXT_KEY_BUILDING_GRANARY</Description>
<Civilopedia>TXT_KEY_CIV5_BUILDINGS_GRANARY_TEXT</Civilopedia>
<Strategy>TXT_KEY_BUILDING_GRANARY_STRATEGY</Strategy>
<ArtDefineTag>ART_DEF_BUILDING_GRANARY</ArtDefineTag>
<MinAreaSize>-1</MinAreaSize>
<ConquestProb>66</ConquestProb>
<HurryCostModifier>25</HurryCostModifier>
<IconAtlas>BW_ATLAS_1</IconAtlas>
<PortraitIndex>0</PortraitIndex>
</Row>
<Update>
<Improvements>
<Row>
<Type>

</Type>
</Row>
</Improvements>
</Update>
</Buildings>
</GameData>

I am not sure how to update the building so that it could add the food to the farms.

 

[Machiavelli24]

Unfortunately Buildings can't add yields to improvements, there is no existing table that provides that functionality. The closest you can get is having Buildings boost resources.

 

[n1ddeh]

Would it be possible to make the granary unlock a new tile?

 

[LeeS]

Not sure what you mean by "unlock a new tile" ?