Helps to calculate values for intervals by transforming potentially unscaled interval (e.g. 08:22 – 17:34) into a series of scaled intervals (e., 08:30 – 09:00, 09:00 – 09:30 …)
To decide whether such a scaled interval is considered to be a interval caused by the original interval is surprisingly tricky.
Example: Scaling of a table with raw time data
Raster the time interval 2007/01/01 6:00 to 2007/01/01 14:30 into 1-hour-intervals
|Operation setting||Choose date columns, scaling and calculation method (other examples see below). |
|TIS Project||Confluence Op Scaling.gzip|
Want to learn more?
Time periods are set in a specific scale (minutes or hours).
Columns of input table
|opt.||Which columns should be evaluated for the identifier?||-|
|Date + Time (from)|
|-||Column containing the start (date+time) of the time period.||-|
|Date + Time (to)|
|-||Column containing the end (date+time) of the time period.||-|
|opt.||Column whose values are counted during scaling.||-|
|-||Input scaling, e.g. 10 minute scale.||-|
|-||Example of calculation method '100% in scale': Scaling 1:00h, start day 0:00. Time period 6:05 to 8:10 occurs only in scaling 7:00 to 8:00.||-|
|Convert 0 lines?|
|-||Prevents the output of rows which exclusively contain 0 values||-|
|Cancel if more than 500,000 rows?|
|-||Cancel if more than 500,000 rows are generated?||-|
Example 1: Different calculation methods
The time interval 2007/01/01 6:00 to 2006/01/01 14:30 is applied to different calculation methods.
See example above:
100% in a 1-hour raster
if Convert 0 lines? is not selected
100% in a 1-hour raster
if Convert 0 lines? is selected
50% in a 1-hour raster
no matter if Convert 0 lines? is selected or not
Example 2: Proportional time*value <> proportional time
The following time interval, value = 27 is rastered with different scaling methods.
Explanation: Scaling interval = 2 minutes (120 seconds) determines the resulting proportion
row 1: half of the interval met, therefore 60/120*27=13.5
rows 2 and 3: interval fully met, therefore 120/120*27=27
row 4: half of the interval met, therefore 60/120*27=13.5
Explanation: Duration of the period in the whole data set (6 minutes = 360 seconds) determines the resulting proportion
row 1: 16:13 – 16:14 = 60 seconds, therefore 60/360*27= 4.5
row 2: 16:14 – 16:16 = 120 seconds, therefore 120/360*27= 9
row 3: 16:16 – 16:18 = 120 seconds, therefore 120/360*27= 9
row 4: 16:18 – 16:19 = 60 seconds, therefore 60/360*27 = 4.5
|There are surprisingly high requirement peaks! – How can I check if they are plausible?|
The following steps can help understand these peaks:
1) Check if the result is due to the scaling method:
2) Check if the peak is due to a few individual values:
3) Check the underlying data.
In case the peaks are really errors, eliminate the faulty data records or time intervals e.g. with TIS:Zeitbereichsfilter (old Wiki) .
There are only points in time. What shall I do?
|Use "Calculation" to add e.g. 30 minutes to create a virtual interval and then analyse with >>Count only start time<<. “Normal scaling” would not make sense in this case.|
The calculated staffing level seems incorrect
|This may be due to the interval selected.|
If in doubt, try using shorter intervals
15 minute scaling can produce strange results for intervals of 10 minutes or less: in case of 50% overlapping e.g.
- A detailed description of how to allocate time data along a time raster (time interval) using different calculation methods can be found under Basics: Scaling and time raster
- This operation can be used to determine how many persons were present in certain time intervals.
- Please also refer to the operation Sum and count
- Please execute Link to calendar only after scaling, otherwise two raster intervals will be created per type of calendar day.