Creating the mosaic dataset for Landscape Modeler

Creating the actual mosaic dataset that the Landscape Modeler application will use is fairly straightforward since the application does not display the mosaicked data except as the result of an analysis. The process includes the following steps.

• Creating a mosaic dataset
• Adding rasters to the mosaic dataset
• Configuring the mosaic dataset
• Clipping the dataset
• Adding and populating fields used by Landscape Modeler
• Adding a function chain on individual layers within the mosaic

Creating a mosaic dataset

The first part of the process is creating the mosaic dataset in a geodatabase. This is accomplished using the Create Mosaic Dataset geoprocessing tool. The dataset will be created in a file geodatabase because the dataset will later be an image service.

Steps:

1. Start ArcCatalog.
2. Create a file geodatabase in the directory where the mosaic dataset will be stored.
3. Right-click the geodatabase and click New > Mosaic Dataset.

   The Create Mosaic Dataset dialog box appears.

4. Type a name in the Mosaic Dataset Name text box.
5. Specify an equal-area projection for the Coordinate System parameter.
6. Expand the Pixel Properties group and click the Pixel Type drop-down arrow to choose the bit depth.

   The pixel depth will be inherited from the first raster, which may not be optimal.

7. Type the number of raster dataset bands that will be supported by the mosaic dataset in the Number of Bands text box.
8. Click OK.

Adding rasters to the mosaic dataset

After the mosaic dataset has been created, the rasters can be added to it. You can add the rasters to the dataset using the Add Rasters To Mosaic Dataset tool in the Mosaic Dataset toolset in the Data Management toolbox.

Steps:

1. Right-click the mosaic dataset and click Add Rasters.
2. For the Raster Type parameter, leave the default of Raster Dataset.
3. Click the Input Data drop-down arrow and choose Dataset.
4. Click the browse button below the Input Data drop-down list and browse to the rasters to add.
5. Select the rasters to add to the dataset and click Add.
6. Check the Update Overviews check box.
Assuming pyramids have been created for the input rasters, there is no need to build overviews or pyramids on the mosaic dataset.
7. Click OK.

Configuring the mosaic dataset

Now that the rasters have been added to the mosaic dataset, it is recommended that you verify some of the default properties to ensure that they appear correctly in Landscape Modeler.

Steps:

1. Right-click the mosaic dataset and click Properties.
2. click the Defaults tab.
3. Click the Default Resampling Method drop-down arrow and choose Nearest Neighbor.
4. Click the General tab and verify that the Pixel Type value matches what was set for the Create Mosaic Dataset tool.
5. Leave the defaults for the other properties.
6. Click OK.

Clipping the dataset

If clipping is necessary, you can add a Clip function to the mosaic dataset.

Steps:

1. Right-click the mosaic dataset and click Properties.
2. Click the Functions tab.
3. Right-click the Mosaic Function node and click Insert > Clip Function.
4. Modify the properties to reflect the extent of the rasters.
5. Click OK on the Raster Function Properties and Mosaic Dataset Properties dialog boxes.

Adding and populating fields used by Landscape Modeler

To work with Landscape Modeler, some fields must be added to the mosaic dataset. These fields allow you to add information that is displayed in the Landscape Modeler interface.

After the fields are initially added to the mosaic dataset, you can populate the fields for each raster. However, for the fields with ranges of values, you must identify the ranges that will be used to classify the values. For example, suppose you have a raster that has values from 0 to 100 with the following classifications:

• 0: No Data
• 1–20: Very poor
• 21–40: Poor
• 41–60: Average
• 61–80: Good
• 81–100: Excellent

Based on these values, you would populate the fields as follows:

Field name	Value
InputRanges	1,21,21,41,41,61,61,81,81,101
OutputValues	1,3,5,7,9
NoDataRanges	0,0
RangeLabels	Very Poor,Poor,Average,Good,Excellent
NoDataRangeLabels	No Data

Note:

The bottom end of each range is inclusive, and the top end is exclusive. There should also not be any spaces between values in the comma-delimited lists.

Steps:

1. Right-click the mosaic dataset and click Properties.
2. Click the Fields tab.
3. Add the following fields using the information provided below.

   Field name	Data type	Alias	Allow Null values	Length
   Title	Text	Title	Yes	50
   Url	Text	URL	Yes	1024
   InputRanges	Text	Input Ranges	Yes	256
   OutputValues	Text	Output Values	Yes	256
   NoDataRanges	Text	NoData Ranges	Yes	256
   RangeLabels	Text	Range Labels	Yes	1024
   NoDataRangeLabels	Text	NoData Range Labels	Yes	1024

4. Populate the fields for each of the rasters.
   1. Populate the Title field with the title of the dataset. This is what the user will see when the raster appears in the Select Layers and Design Model views of the Landscape Modeler pane.
   2. Optionally populate the Url field with the URL to an image service that can be used to preview the raster data as a layer on the map.
   3. Identify ranges to classify the values for InputRanges and enter a comma-separated list of input range bounds that will be used as the InputRanges argument to the Remap function on that raster.
   4. Identify ranges to classify the values for OutputValues and enter a comma-separated list of output values that will be used as the OutputValues argument to the Remap function on that raster.
   5. Identify ranges to classify the values for NoDataRanges and enter a comma separated list of NoData range bounds that will be used as the NoDataRanges argument to the Remap function on that raster.
   6. Identify ranges to classify the values for RangeLabels and enter a comma separated list of labels for each input range.
   7. Identify ranges to classify values for NoDataRangeLabels and enter a comma-separated list of labels for each NoData range.

Adding a function chain on individual layers within the mosaic

When the fields and values have been added, a function chain needs to be added to allow the option to display NoData as NoData or zero (0) values. This allows the Landscape Modeler user to select whether an individual layer's NoData values are used as NoData in the analysis, thus excluding analysis results from all areas where the participating raster contains NoData; or will be used as 0 in the analysis, though the analysis will still produce results over areas containing 0 values.

Steps:

1. Start ArcMap.
2. Add the mosaic dataset to the map.
3. Right-click the mosaic dataset in the table of contents and click Open > Attribute Table.
4. Click the Functions tab.
5. Right-click the RasterInfo Function node and click Insert > Local Function.
6. In the Operations list on the Raster Function Properties dialog box, choose Con.
7. Change the default values as needed and click OK.
8. Repeat steps 5 through 7to add an IsNull function beneath the Con function.