Exercise 3: Finding temperature difference between two time steps

Complexity: Beginner Data Requirement: ArcGIS Tutorial Data Setup Data Path: C:\arcgis\ArcTutor\NetCDF Goal: Perform analysis using a netCDF file.

In this exercise, you'll create a model to find the temperature difference between two time steps. This exercise will take approximately 20 minutes to complete.

Creating a new toolbox

You'll first create a new toolbox to store the model you will create in this exercise.

Steps:

1. Click the Catalog Window button on the Standard toolbar to open the Catalog window.
2. Click the Default Geodatabase button on the Catalog.
3. Right-click Default.gdb and click New > Toolbox.

   

4. Change the name of the toolbox you just created from Toolbox to NetCDF.

   

Creating a new model

You'll create a new model and name it TemperatureDifference.

Steps:

1. Right-click the NetCDF toolbox and click New > Model.

   

2. On the model's Main menu, click Model > Model Properties.

   

3. Click the General tab.
4. Type TemperatureDifference in the Name text box.
5. Type Temperature Difference in the Label text box.
6. Click OK to close the dialog box.

   

Building the Temperature Difference model

You'll add the netCDF file and the Make NetCDF Raster Layer tool in your model to create two raster layers for the years 1935 and 1940.

Steps:

1. From your NetCDF folder in Windows Explorer, drag the temperature.nc file onto your model.
2. Locate the Make NetCDF Raster Layer tool and drag it onto your model.
3. Connect the temperature.nc variable to the Make NetCDF Raster Layer tool.
4. Double-click the Make NetCDF Raster Layer tool.
5. Type tmin_1935 in the Output Raster Layer text box.
6. Click the Dimension Values arrow and choose the year dimension.
7. Click the cell next to year in the Value column, click the arrow, then choose 1/1/1935.
8. Click OK on the Make NetCDF Raster Layer dialog box.

   

9. Locate the Make NetCDF Raster Layer tool again and drag it onto your model.
10. Connect the temperature.nc variable to the resulting Make NetCDF Raster Layer (2) tool.
11. Double-click the Make NetCDF Raster Layer (2) tool.
12. Type tmin_1940 in the Output Raster Layer text box.
13. Click the Dimension Values arrow and choose the year dimension.
14. Click the cell next to year in the Value column, click the arrow, then choose 1/1/1940.
15. Click OK on the Make NetCDF Raster Layer (2) dialog box.

    

Finding temperature difference

Now you'll finish up your model to find the minimum temperature difference between years 1935 and 1940 by subtracting two raster layers.

Steps:

1. Locate the Minus tool in the Spatial Analyst or 3D Analyst toolbox and drag it onto your model.
2. Connect tmin_1935 then tmin_1940 to the Minus tool.
3. Right-click the output of the Minus tool and click Rename.
4. Type Temperature_Difference in the text box and click OK.
5. Right-click Temperature_Difference and click Add To Display.
6. Click the Auto Layout button to arrange the model elements.

   

7. Click the Save button to save your model.
8. Click the Run button to run your model. The output raster layer is added to the table of contents.
9. Click the legend of the Temperature_Difference layer and choose a color ramp for better display.

   

Saving the map document

You are done with the exercise. However, you may want to save the map document to explore other functionalities.

Steps:

1. On the main menu, click File > Save.