How to transform datum in ArcGIS?

Here is the video explaining how to transform datum in ArcGIS:

Steps to transform datum in ArcGIS

Objectives:

• Changing projection from geocentric (EVEREST 1830) to geographic (WGS84)
• Create KML from shapefile
• Visualize in Google Earth
• Digitizing feature in Google Earth
• Create Shapefile from KML
• Defining projection
• Changing projection from geographic (WGS84) to geocentric (Everest1830)

Data Necessary:

• nep_vdc.shp

Task 1: Changing Projection from EVEREST1830 to WGS84

1. Add nep_vdc.shp shapefile from exercise VII folder.
2. Check its coordinate system; if it is not Everest_Bangladesh_Transverse_Mercator, define it as such.
3. Now, create a custom geographic transformation using Data Management Tools > Projections and Transformations > Create Custom Geographic Transformation.

Create Custom Geographic Transformation:

• Geographic Transformation Name: Everest1830_to_WGS84
• Input: GCS_Everest_1830
• Output: GCS_WGS_1984
• Method: MOLODENSKY
• Parameters:
  • X-axis transition: 282
  • Y-axis transition: 726
  • Z-axis transition: 254

4. Now, perform the datum transformation from Everest1830 to WGS84:
   • Click on Management Tools > Projections and Transformations > Features > Project.

Run Project:

• Input: nep_vdc
• Output: Provide desired location and name nep_vdc_WGS84
• Output coordinate system: GCS_WGS_1984
• Geographic Transformation (Optional): Everest1830_to_WGS84

Once complete, the coordinate system of nep_vdc will be changed to WGS84.

Task 2: Create KML File from the Shapefile

1. Ensure you have the shapefile components (.dbf, .sbn, .sbx, .shx, .shp, .prj).
2. Open ArcToolbox, navigate to Conversion Tools > To KML > Layer to KML.

Layer to KML:

• Layer: Choose Nep_vdc_WGS84.shp.
• Output File: Select the location and name the file vdc.kmz.
• Layer Output Scale: 1

Task 3: Visualizing in Google Earth

1. Open vdc.kmz in Google Earth.
2. Ensure the shape is visible and tick the boxes in the Places panel.
3. Double-click vdc to visualize the map in Google Earth.

Task 4: Creating Shapefile from KML (Digitizing in Google Earth)

1. Navigate to your district (e.g., Dhulikhel).
2. Use the Add Polygon/Add Path icon to digitize the desired feature.
3. In the Places panel, right-click the new feature (e.g., Dhulikhel), and click Save Place As:
   • File Name: Dhulikhel.kml
   • Save as type: KML (*.kml)

Task 5: Converting KML to Shapefile

1. In ArcToolbox, navigate to Conversion Tools > From KML > KML to Layer.
2. Input the KML file (Dhulikhel.kml) and provide the output location and name.

Task 6: Defining Projection

• Use Data Management > Projection and Transform > Define Projection to define the projection as WGS84 for the shapefile.

Task 7: Datum Transformation from WGS84 to Everest1830

1. Run Create Custom Geographic Transformation:

   • Name: WGS84_to_Everest1830
   • Input: GCS_WGS_1984
   • Output: GCS_Everest_1830
   • Method: MOLODENSKY
   • Parameters:
     • X-axis transition: -282
     • Y-axis transition: -726
     • Z-axis transition: -254

2. Perform the datum transformation:

   • Input: Dhulikhel.shp
   • Output: Provide the desired location and name.
   • Output coordinate system: GCS_Everest_1830
   • Geographic Transformation: WGS84_to_Everest1830

After the transformation, the coordinate system will be changed from WGS84 to Everest1830.