most of that the data into change the paste Rename the sheet this:

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Maude Cunningham
5 years ago
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have any difficulty understanding any of

The goal of this portion of the tutorial

2) The data will be manipulated with some

3) The data will then be written out to a

Hooman s tutorial if you decide to follow

textt file directly, but I prefer to copy

1 Tutorial 2: A more advanced and useful macro Now that you are somewhat familiar with the programing environment of VBA, this will introduce you, quickly, to some of the more useful commands you can do within VBA, note that at any time if you have any difficulty understanding any of the commands I am using, the help section in VBA is very good, simply hit F1 and search for the command. The goal of this portion of the tutorial is to: 1) Read some data in from a sheet. The data will be stored in a two dimensional array. 2) The data will be manipulated with some loops and some if statements. 3) The data will then be written out to a different sheet. These simple commands will allow you to do virtually anything in excel that you could do in your C++ programing course (you could even program a kriging or inverse distance program!). Of course theree are added benefits in excel like user interfaces and buttons that you can add (ActiveX controls). But I will leave that to your own self study, note most of that is covered in Hooman s tutorial if you decide to follow it. Part 1: Read in the data Theree are a number of ways to set up a program. You can have excell read the data from a textt file directly, but I prefer to copy and paste the data into excel and have the program read it inn from a sheet. This way you can easily change the data in the sheet, not the text file. So, first open the data I have givenn you in text pad or note pad. Copy the data and paste into excel, you might have to use the Text to Columns button in the data tab if each row is in one cell. Simply select all the data and click this button, use the delimitedd option, clickk next, and finally click on space then finish. Rename the sheet to input_data. Also rename the second sheet too output_data. You should have something like this:

2 The data is an environmental data set with soil contamination levels. now we have to read the data into an array with VBA. There is also a rocktype and land use variable. Ok, 1) First make a new macro called data_analysis : 2) Now let s look at the command active cell. This is a useful command for reading in data from the sheet. It is essentially the location that is highlighted on the workbook with a box, i.e. right now the active cell is A2: 3) We can extract the value of this cell and store it in a variable.. First activate cell A2 and read it in with the following code in your new macro. This will copy that data header (cell A1) to the output sheet. Run the code and see what happens Range("A1").Select v = ActiveCell.Value Sheets("output_data").Select Range("A1").Select ActiveCell.Value = v

3 4) Debuging is an important part of programing. When in the VBA IDE you can run your code by pressing F5. You can also run it line by line if you want (helps with debugging long programs). Click just to the left of the line you want to stop at (the line is highlighted red) and then hit F5, every time you hit F5 the code jumps to the next stop, right now my program has stopped just BEFORE switching to the output_data sheet in the code below. Note, while debugging, if you mouse over a variable you can see the value of that variable, try it. 5) Let s read in all the header data. We could repeat the above block of code for each header, but this seems redundant (don t type in the following, but this is one way too do it):

4 Part 2: Use some loops 6) A better way to copy the header data is it to use a loop. Consider this block of code. There are two VERY importantt and powerful commands here, the offset and the loop. The offset lets you activate different cells andd the loop lets you loop until you reach the end of the data (until the last cell is empty) IMPORTANT NOTE: if you are prone to seizures, the screen flicker can be very annoying (and slows down the program). You can turn this off with Application.ScreenUpdating = False at the start of your code: 7) Now, let s read in the real data. First we need an array to store the data, so define an array A at the start of your code: Dim A(9999, 999) As Double 8) Now loop over the data and read it into the array, here is my program so far (next page):

5 Part 3 (HARD): Manipulate the data and write it out ( you can consider part 3: easy below if this gets frustrating) 9) Now I willl leave the last part up to you, you need to manipulate the data and write it out. Let s say that when Cdd was measured in forest (Land use indicator==1) the measurement was biased, and is 25% below the true value. Your task is to output the corrected data set in the output_data sheet. Also, when the Cd value is >2.0 it exceeds the local environmental regulations. Highlight thesee samples with a red background like the following: Part 3 (EASY): Manipulate the data and write it out. 9) Rather than considering the cell formatting (which is nice butt may not be that important), if you are frustrated, consider adding a 12 th column where you just correct the Cd value measured in forest. This involves one added if statement right before you finish your final do loop.

6 If you get board: Of course there are endless things you could do now that you know how to use do loops and if statements. Maybe try inverse distance modeling at a unsampled location in space, say x=2, y=2. I suppose you could loop over all locations in space (0 >6 in x and 0 >6 in y, with a 0.1x0.1 sized grid) and perform inverse distance modeling using the given data for Cd. Then you could highlight the expected areas that are above the threshold

Civil Engineering Computation

Civil Engineering Computation First Steps in VBA Homework Evaluation 2 1 Homework Evaluation 3 Based on this rubric, you may resubmit Homework 1 and Homework 2 (along with today s homework) by next Monday