Map data
Match Timeline Data Position Values
Match timeline provides positions for various events. Here is a list of the maps and the bounds used for that. Example in Javascript on how to use maps and positions : http://jsfiddle.net/ow4tsbne
Name  Image  Notes 

Summoner's Rift  https://ddragon.leagueoflegends.com/cdn/10.18.1/img/map/map11.png  Map bounds :

Twisted Treeline  https://ddragon.leagueoflegends.com/cdn/10.3.1/img/map/map10.png  Map bounds :

Howling Abyss  https://ddragon.leagueoflegends.com/cdn/10.18.1/img/map/map12.png  Map bounds :

Nexus Blitz  https://ddragon.leagueoflegends.com/cdn/10.18.1/img/map/map21.png 
Additionally, list of buildings :
Summoner's Rift :
{
"BLUE_TOP_LANE_OUTER_TURRET":{"x":981,"y":10441},
"BLUE_TOP_LANE_INNER_TURRET":{"x":1512,"y":6699},
"BLUE_TOP_LANE_BASE_TURRET":{"x":1169,"y":4287},
"BLUE_MID_LANE_OUTER_TURRET":{"x":5846,"y":6396},
"BLUE_MID_LANE_INNER_TURRET":{"x":5048,"y":4812},
"BLUE_MID_LANE_BASE_TURRET":{"x":3651,"y":3696},
"BLUE_BOT_LANE_OUTER_TURRET":{"x":10504,"y":1029},
"BLUE_BOT_LANE_INNER_TURRET":{"x":6919,"y":1483},
"BLUE_BOT_LANE_BASE_TURRET":{"x":4281,"y":1253},
"BLUE_TOP_LANE_NEXUS_TURRET":{"x":1748,"y":2270},
"BLUE_BOT_LANE_NEXUS_TURRET":{"x":2177,"y":1807},
"RED_TOP_LANE_OUTER_TURRET":{"x":4318,"y":13875},
"RED_TOP_LANE_INNER_TURRET":{"x":7943,"y":13411},
"RED_TOP_LANE_BASE_TURRET":{"x":10481,"y":13650},
"RED_MID_LANE_OUTER_TURRET":{"x":8955,"y":8510},
"RED_MID_LANE_INNER_TURRET":{"x":9767,"y":10113},
"RED_MID_LANE_BASE_TURRET":{"x":11134,"y":11207},
"RED_BOT_LANE_OUTER_TURRET":{"x":13866,"y":4505},
"RED_BOT_LANE_INNER_TURRET":{"x":13327,"y":8226},
"RED_BOT_LANE_BASE_TURRET":{"x":13624,"y":10572},
"RED_TOP_LANE_NEXUS_TURRET":{"x":12611,"y":13084},
"RED_BOT_LANE_NEXUS_TURRET":{"x":13052,"y":12612},
"BLUE_TOP_LANE_INHIBITOR":{"x":1171,"y":3571},
"BLUE_MID_LANE_INHIBITOR":{"x":3203,"y":3208},
"BLUE_BOT_LANE_INHIBITOR":{"x":3452,"y":1236},
"RED_TOP_LANE_INHIBITOR":{"x":11261,"y":13676},
"RED_MID_LANE_INHIBITOR":{"x":11598,"y":11667},
"RED_BOT_LANE_INHIBITOR":{"x":13604,"y":11316}
}