How to Create Points from Contour Lines in ArcGIS and Prepare Them for Analysis

 

Working with contour lines in ArcGIS often requires converting them into evenly spaced points. These points can then be clipped to a study area and cleaned up for further analysis, such as terrain modeling, hydrology, or GIS-based surveys.

In this guide, I’ll walk you through three essential steps:

1. Creating points from contour lines at a fixed interval
2. Clipping those points to your study boundary
3. Rounding coordinate values for clean attribute data

Let’s dive in! 🚀

Step 1: Create Points at a Specific Interval Along Contour Lines

Sometimes contour lines don’t have enough vertices, which makes it hard to extract accurate elevation data. To solve this, we first densify the lines and then convert vertices into points.

1.1 Densify the Contour Lines

• Go to ArcToolbox → Editing Tools > Densify.
• Input Features: Your contour line layer
• Output Feature Class: Name it something like Contours_Densified
• Densification Method: Select Distance
• Distance: Enter the spacing you want (e.g., 50 meters)

This creates extra vertices along the contour lines at your chosen interval.

1.2 Convert Vertices to Points

• Go to ArcToolbox → Data Management Tools > Features > Feature Vertices To Points.
• Input Features: Contours_Densified
• Output Feature Class: e.g., Contour_Points
• Point Type: Choose ALL

Now you have a point feature class where each point is evenly spaced (e.g., every 50 meters) along your contours.

Step 2: Clip the Points to Your Study Area

If you created points for a large region, you might only need them inside your project boundary. Clipping saves processing time and storage.

• Go to ArcToolbox → Analysis Tools > Extract > Clip.
• Input Features: Your point layer (e.g., Contour_Points)
• Clip Features: Your boundary polygon (e.g., Study_Area)
• Output Feature Class: e.g., Contour_Points_Study_Area

ArcGIS will create a new layer containing only the points that fall inside your boundary. All attribute data from the original points are preserved.

Step 3: Round the Coordinate Data

GIS datasets often contain long decimal values that aren’t practical for reporting. You can round coordinates to make them easier to read.

• Open the Attribute Table of your point layer.

• Click Table Options > Add Field.

• Name: Easting_Rounded

• Type: Double

• Right-click the new field → Field Calculator.

  Choose Python as parser.
  
  Enter the formula:
  round(!POINT_X!, 3)
  Replace POINT_X with the actual field name of your X coordinate.

• Enter the formula:

• round(!POINT_X!, 3)

• Replace POINT_X with the actual field name of your X coordinate.

For example:

• Original: 592744.6875
• Rounded: 592744.688

This makes your dataset cleaner and easier to interpret.