Sometimes data is provided in CSV format from other packages that contain Latitude and Longitude information. To ensure this data to be seen and read in Surpac, it is necessary to convert the data into a grid reference system. In this example, the reference will be MGA94, however the technique can be equally applied to other grid systems.
The first step is to take the csv data and turn it into a string file. This can be done in numerous ways including via excel, using a macro or importing the file into Surpac. For this example we will use excel and then import the file.
The csv currently looks like the image below, with Longitude in column 1, Latitude in column 2 and height in column 3. The other fields will be carried through to the resulting string file but aren’t important for the conversion.
Use excel and add some dummy data so that each row has a string number, Y, X and Z value.
We can use the existing heights in the csv for our z values. It doesn’t matter if all the string numbers, Y and X values are the same at this point.
You can now see that string number is in column 1, Y is in column 2, X is in column 3, Height in column 4 and so on. Having it in this format allows us to import it into Surpac as a string file.
NOTE: It is important that the Latitude and Longitude are stored in a dfield so that the decimal place precision is preserved.
Import the file into Surpac.
Use File -> Import -> Data from one file for this purpose.
Map the fields (columns) as shown below:
We now have a string file (transformed_data1.str) with Longitude in the d1 field and Latitude in the d2 field.
Transform the Latitude and Longitude into MGA values.
Use File tools -> Transformations -> Lat/Long to transverse mercator
Select the file to transform and select the output name.
- Pay attention to the input fields and be careful to match the Lats and Longs to the right field.
- Output fields should be Y for northing and X for easting. The TM zone can go into any empty dfield.
If all the parameters have been filled out correctly, a string file will be created that is in MGA coordinate system. In this example, the string file name will be new_transformed1.str