CREATE VIEW [dbo].[LatestDeviceLocation]
AS
SELECT DISTINCT t.Imei, t.Accuracy, t.UserId, t.Lat, t.Lng, t.Timestamp
FROM (SELECT Imei, MAX(Timestamp) AS latest
    FROM      dbo.DeviceLocation
    GROUP BY Imei) AS m INNER JOIN
    dbo.DeviceLocation AS t ON t.Imei = m.Imei AND t.Timestamp = m.latest
GO

/****** Object:  Index [GangHeatMapIndex]    Script Date: 02/26/2015 22:38:38 ******/
CREATE NONCLUSTERED INDEX [GangHeatMapIndex] ON [dbo].[DeviceLocation]
(
    [UserId] ASC,
    [Timestamp] ASC,
    [Imei] ASC
)
INCLUDE ( [DeviceLocationId],
[Accuracy],
[Lat],
[Lng]) WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO