Hi, this is Jeff Kitchen.
I'm the surface water specialist
for the data section in California.
I would like to talk about the SAC-conversion spreadsheet,
which can be used to convert data
from an azimuth-stadia-survey
typically obtained using a laser or optic engineer's level
into the cartesian coordinate format
needed for input into the iRIC program.
The iRIC-SAC program is the preferred software platform
for running the USGS Slope Area Computation 1-D model,
otherwise known as SAC.
This program requires input data
that are in a X, Y, Z format
or, to be more specific to our surveys,
an Easting, Northing, and Elevation.
If you are using GNSS or a Total Station for the survey
you can easily create an input file
from the instrument in this format.
However, if you are surveying with a laser or optic level,
your data will be in polar coordinates,
which are measured using angles and distances
and will need to be converted.
Let's open the SAC-conversion spreadsheet and take a look.
The first sheet, named 'SurveyData',
is where you will input your field data.
The second sheet is the plan view plot of our data.
The third sheet, named 'Output',
is where the macro creates the final output file.
There should be no need to change
or interact with anything on this page.
The last sheet, named 'Read Me',
contains some of the basic instructions
I will be discussing in this video.
It also contains my contact information
if you have any questions
or issues regarding this spreadsheet.
Let's take a closer look at the 'SurveyData' sheet.
Data that are input into the yellow highlighted cells
on the left are converted into the X, Y, Z format,
which can be seen in the gray cells on the right.
Let's start with Hub-1.
Since this is the starting point of your survey,
the angle and distance will be zero.
The elevations of the hubs are not used in the planview
or the computations performed by the spreadsheet
and therefore are not required.
However, I recommend entering them
for consistency between the field notes and input file.
Enter a remark if you wish.
If you have additional hubs, enter those now.
The program assumes that Hub-2 was surveyed from Hub-1,
Hub-3 was surveyed from Hub-2, and so forth.
When one enters the angles and distance
on the shot of Hub-2,
the program will calculate a coordinate for Hub-2
based on the coordinate for Hub-1.
Proceed to enter the hubs in the order they were surveyed.
You can enter up to seven hubs.
The spreadsheet can be modified if more are needed.
Once all the hubs are entered,
we can start entering the rest of our survey data.
The 'Note' column is the name of the surveyed point.
A specific naming convention must be followed,
as described in the SAC-Tutorial.
Angles can be entered as decimal degrees
or degrees and minutes.
If entering decimal degrees in the 'Degrees' column,
simply leave the 'Minutes' column as zero.
The 'Remarks' column is where we can enter details
related to the point,
such as 'fair debris line' for a high-water mark.
Enter a number in the 'Hub' column
corresponding to the hub from which that point was surveyed.
For example, if all of the survey
was done from a single setup,
you would simply enter a '1' for each point.
When all the points are entered,
click on the 'PlanView' sheet
to see a plot of the X-Y coordinates.
Due to the auto-scaling feature of the plot,
this planview may not be to the same scale along both axes,
but it should still allow you
to check for any obvious entry errors.
If you see a point that plots in an unexpected position,
double-check the entry and modify if needed.
The points will most likely plot on both sides of the axis.
To avoid negative values,
we can add an offset to our coordinates
to make them all positive.
We add this on the 'SurveyData' sheet,
using the 'Offset' cell.
The value entered is added
to both the Easting and Northing coordinates.
We can see in this example that adding an offset of 300
causes all the values to be positive.
Once all of your points
have been properly entered and adjusted,
you are ready to export the data.
From the 'SurveyData' sheet,
simply enter a file name into the highlighted cell
and click the blue 'Export File' button
to create the output file.
We now have a file that is properly formatted
for input into the iRIC and SAC-GUI programs.
If you need help, contact your field office chief,
surface water specialist,
or indirect measurement specialist.