You can create a photometric data file in the IES (Illuminating Engineering Society)
LM-63-1991 standard file format for photometric data.

The luminous intensity distribution (LID) of a luminaire is measured at the nodes
of a photometric web for a fixed set of horizontal and vertical angles. The poles
of the web lie along the vertical axis, with the nadir corresponding to a vertical
angle of zero degrees. The horizontal axis corresponds to a horizontal angle of zero
degrees and is oriented parallel to the length of the luminaire. This type of photometric
web is generated by a Type C goniometer and is the most popular in North America;
other types of goniometry are supported by the IES standard file format but are not
discussed here.

The photometric data is stored in an ASCII file. Each line in the file must be less
than 132 characters long and must be terminated by a carriage return/line-feed character
sequence. Longer lines can be continued by inserting a carriage return/line-feed character
sequence.

Each field in the file must begin on a new line and must appear exactly in the following
sequence:

1. IESNA91
2. [TEST] The test report number of your data
3. [MANUFAC] The manufacturer of the luminaire
4. TILT=NONE
5. 1
6. The initial rated lumens for the lamp used in the test or -1 if absolute photometry
   is used and the intensity values do not depend on different lamp ratings.
7. A multiplying factor for all the candela values in the file. This makes it possible
   to easily scale all the candela values in the file when the measuring device operates
   in unusual units—for example, when you obtain the photometric values from a catalog
   using a ruler on a goniometric diagram. Normally the multiplying factor is 1.
8. The number of vertical angles in the photometric web.
9. The number of horizontal angles in the photometric web.
10. 1
11. The type of unit used to measure the dimensions of the luminous opening. Use 1 for
    feet or 2 for meters.
12. The width, length, and height of the luminous opening. It is normally given as 0
    0 0.
13. 1.0 1.0 0.0
14. The set of vertical angles, listed in increasing order. If the distribution lies
    completely in the bottom hemisphere, the first and last angles must be 0آ° and 90آ°,
    respectively. If the distribution lies completely in the top hemisphere, the first
    and last angles must be 90آ° and 180آ°, respectively. Otherwise, they must be 0آ° and
    180آ°, respectively.
15. The set of horizontal angles, listed in increasing order. The first angle must be
    0آ°. The last angle determines the degree of lateral symmetry displayed by the intensity
    distribution. If it is 0آ°, the distribution is axially symmetric. If it is 90آ°, the
    distribution is symmetric in each quadrant. If it is 180آ°, the distribution is symmetric
    about a vertical plane. If it is greater than 180آ° and less than or equal to 360آ°,
    the distribution exhibits no lateral symmetries. All other values are invalid.
16. The set of candela values. First, all the candela values corresponding to the first
    horizontal angle are listed, starting with the value corresponding to the smallest
    vertical angle and moving up the associated vertical plane. Then, the candela values
    corresponding to the vertical plane through the second horizontal angle are listed,
    and so on until the last horizontal angle. Each vertical slice of values must start
    on a new line. Long lines may be broken between values as needed by following the
    instructions given earlier.

Example of Photometric Data File

The following is an example of a photometric data file.