Q群里面有人说添加以下语句开启贸易路线视野没有用
<Effect type="Data" amount="1.00" subtype="EnableTradeRouteLOS" relativity="Absolute">
<Target type="Player"/></Effect>
我告诉他需要先研究驿马车升级一次贸易路线才能获得视野，然后他又问怎样才能在发现时代获得贸易马车视野？
根据经验，这个设定不在techtreey，有可能是protoy里面的Flag或Unittype，也有可能在traderoutes.xml里面，当然也有可能是主程序写死的。在查了一下protoy后并没有发现有什么可疑的flag或unittype
贸易马拉雪橇
<Unit id ='479' name ='Travois'>
<DBID>511</DBID>
<DisplayNameID>29375</DisplayNameID>
<ObstructionRadiusX>0.9900</ObstructionRadiusX>
<ObstructionRadiusZ>2.4900</ObstructionRadiusZ>
<MaxVelocity>4.0000</MaxVelocity>
<MaxRunVelocity>6.0000</MaxRunVelocity>
<MovementType>land</MovementType>
<AnimFile>units\trade\travois.xml</AnimFile>
<Icon>units\trade\travois_icon_64</Icon>
<PortraitIcon>units\trade\travois_icon_portrait</PortraitIcon>
<RolloverTextID>29374</RolloverTextID>
<ShortRolloverTextID>29373</ShortRolloverTextID>
<InitialHitpoints>240.0000</InitialHitpoints>
<MaxHitpoints>240.0000</MaxHitpoints>
<LOS>15.0000</LOS>
<TrainPoints>30.0000</TrainPoints>
<MinimapColor red ='0.0000' blue ='0.0000' green ='0.0000'></MinimapColor>
<Armor type ='Ranged' value ='0.9000'></Armor>
<UnitType>LogicalTypeHealed</UnitType>
<UnitType>LogicalTypeHandUnitsAutoAttack</UnitType>
<UnitType>LogicalTypeGarrisonInShips</UnitType>
<UnitType>LogicalTypeRangedUnitsAutoAttack</UnitType>
<UnitType>LogicalTypeVillagersAttack</UnitType>
<UnitType>LogicalTypeHandUnitsAttack</UnitType>
<UnitType>LogicalTypeRangedUnitsAttack</UnitType>
<UnitType>Unattackable</UnitType>
<UnitType>RailroadUnit</UnitType>
<UnitType>Unit</UnitType>
<UnitType>UnitClass</UnitType>
<UnitType>HasBountyValue</UnitType>
<Flag>NoProjectileDamage</Flag>
<Flag>NonCollideable</Flag>
<Flag>OrientUnitWithGround</Flag>
<Flag>NonAutoFormedUnit</Flag>
<Flag>Invulnerable</Flag>
<Flag>InvulnerableIfGaia</Flag>
<Flag>NoHPBar</Flag>
<Flag>DoNotCreateUnitGroupAutomatically</Flag>
<Flag>Tracked</Flag>
<Command page ='10' column ='0'>Delete</Command>
</Unit>
驿马车
<Unit id ='480' name ='Stagecoach'>
<DBID>512</DBID>
<DisplayNameID>29379</DisplayNameID>
<ObstructionRadiusX>0.9900</ObstructionRadiusX>
<ObstructionRadiusZ>2.4900</ObstructionRadiusZ>
<MaxVelocity>7.0000</MaxVelocity>
<MaxRunVelocity>9.0000</MaxRunVelocity>
<MovementType>land</MovementType>
<AnimFile>units\trade\trade_stagecoach.xml</AnimFile>
<ImpactType>Wood</ImpactType>
<Icon>units\trade\stagecoach_icon_64x64</Icon>
<PortraitIcon>units\trade\stagecoach_portrait</PortraitIcon>
<RolloverTextID>29378</RolloverTextID>
<ShortRolloverTextID>29377</ShortRolloverTextID>
<InitialHitpoints>240.0000</InitialHitpoints>
<MaxHitpoints>240.0000</MaxHitpoints>
<LOS>15.0000</LOS>
<MinimapColor red ='0.0000' blue ='0.0000' green ='0.0000'></MinimapColor>
<Armor type ='Ranged' value ='0.1000'></Armor>
<UnitType>LogicalTypeHealed</UnitType>
<UnitType>LogicalTypeHandUnitsAutoAttack</UnitType>
<UnitType>LogicalTypeGarrisonInShips</UnitType>
<UnitType>LogicalTypeRangedUnitsAutoAttack</UnitType>
<UnitType>LogicalTypeVillagersAttack</UnitType>
<UnitType>LogicalTypeHandUnitsAttack</UnitType>
<UnitType>LogicalTypeRangedUnitsAttack</UnitType>
<UnitType>HasBountyValue</UnitType>
<UnitType>UnitClass</UnitType>
<UnitType>Unit</UnitType>
<UnitType>RailroadUnit</UnitType>
<UnitType>Unattackable</UnitType>
<Flag>NoHPBar</Flag>
<Flag>Invulnerable</Flag>
<Flag>InvulnerableIfGaia</Flag>
<Flag>NoProjectileDamage</Flag>
<Flag>NonCollideable</Flag>
<Flag>OrientUnitWithGround</Flag>
<Flag>NonAutoFormedUnit</Flag>
<Flag>Tracked</Flag>
<Command page ='10' column ='0'>Delete</Command>
</Unit>
对比马拉雪橇与驿马车后，基本上可疑否认是flag或者unittype了。接下来就是去traderoutes.xml寻找了，打开traderoutes.xml后，随便观望了一下，发现有个<grantsvisibility/>非常可疑（看英文名称，然后等级2与等级3都有，就只有等级1-FindNugget没有），然后通过几次测试得出，就是<grantsvisibility/>定义了贸易路线视野，给FindNugget加上，再利用科技开启贸易路线单位视野，再建造一个贸易站就能获得视野了。
发现时代建造贸易站也能获得贸易马车视野 
再来重复一下获得贸易路线单位视野的三个条件：
1.traderoutes.xml对于的贸易路线等级要添加<grantsvisibility/>
2.要改良以下科技
<Effect type="Data" amount="1.00" subtype="EnableTradeRouteLOS" relativity="Absolute">
<Target type="Player"/></Effect>
3.在贸易路线建造一个贸易站
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