ArcGIS Pro Tutorial: Reclassify and Convert Raster to Polygon Shapefile & Calculate Area Using ArcGIS Pro

Getting Started

Before beginning this tutorial, ensure you have:

• ArcGIS Pro installed and licensed
• A raster dataset (e.g., land use, elevation, or satellite imagery)
• Basic familiarity with the ArcGIS Pro interface

Step 1: Reclassify Raster Data

Opening the Reclassify Tool

1. Open ArcGIS Pro and create a new project or open an existing one
2. Add your raster dataset to the map
3. Navigate to the Analysis tab in the ribbon
4. Click on Tools to open the Geoprocessing pane
5. Search for “Reclassify” and select the Reclassify tool

Setting Reclassification Parameters

1. In the Input raster field, select your raster dataset
2. Choose the Reclass field (usually the Value field for single-band rasters)
3. Define your reclassification ranges in the table:
   • From: Lower boundary of the range
   • To: Upper boundary of the range
   • New Value: The value to assign to this range
4. You can add new ranges using the +Add button or delete existing ranges
5. Select Save reclass as to save your reclassification scheme for future use
6. Define the Output raster name and location
7. Click Run to execute the reclassification

Step 2: Convert Raster to Polygon Shapefile

Using the Raster to Polygon Tool

1. Return to the Geoprocessing pane or open it again
2. Search for “Raster to Polygon” or navigate to Conversion Tools > From Raster > Raster to Polygon
3. Set the following parameters:
• Input raster: Select your reclassified raster
• Field: Choose the field to convert to polygons (typically the Value field)
• Output feature class: Define the output polygon shapefile name and location
• Simplify polygons: Choose whether to simplify polygon boundaries
4. Click Run to convert your raster to polygons

Optimizing the Conversion Process

For better performance and cleaner results:

• Ensure your reclassified raster has a reasonable number of unique values
• Consider using the Simplify polygons option for cleaner boundaries
• Check the output coordinate system to ensure it matches your project requirements

Step 3: Calculate Area

Adding Area to Polygon Attributes

1. Right-click your polygon layer in the Contents pane
2. Select Attribute Table to open the table view
3. Click the Table Options button (three dots or plus sign)
4. Select Add Field
5. Configure the new field:
   • Name: Area_SqM or Area_Acres (depending on your preference)
   • Type: Double
   • Alias: Area in Square Meters or Area in Acres
6. Click Save to create the field

Calculating Area Values

1. Right-click the new area field header in the attribute table
2. Select Calculate Field
3. In the calculator window:
   • Set the Parser to Python 3
   • For square meters: !shape.area@squaremeters!
   • For acres: !shape.area@acres!
   • For hectares: !shape.area@hectares!
4. Click Calculate to populate the area values

Advanced Tips and Best Practices

Data Preparation

• Always check your raster’s coordinate system before reclassification
• Consider resampling your raster if it has very high resolution
• Use meaningful new values in reclassification for easier interpretation

Performance Optimization

• For large rasters, consider clipping to your area of interest first
• Use appropriate data types to minimize file sizes
• Save intermediate results for complex workflows

Quality Control

• Verify reclassification results by examining the output raster
• Check polygon boundaries for any unexpected gaps or overlaps
• Validate area calculations using known values or manual measurements

Common Applications

This workflow is commonly used for:

• Land use and land cover analysis
• Environmental impact assessments
• Urban planning and development analysis
• Agricultural land classification
• Forest type mapping
• Watershed management studies