Datums and Projections - Hawaii & Pacific GIS User Groups

Tips and Tricks for Hawaii Datums and Projections

Understanding Hawaii Coordinate Systems - What are the coordinate systems most frequently used in Hawaii? Here is a map showing the State Plane and UTM zones, with a table of common Hawaii coordinate systems and their .prj file locations.
Organizing Hawaii Coordinate Systems for Quick Use - Navigating through the thousands of ArcGIS coordinate systems to find the one you need can be time consuming! Here is a simple way to organize your most-used .prj files so that you can access them with only 2 or 3 mouse-clicks. This document also contains the table of common Hawaii coordinate systems.
Setting the Datum Transformation Method in ArcMap - Here are step-by-step instructions for setting the datum tranformation method for a data frame in ArcMap. This enables correct datum transformation when projecting on-the-fly and also when exporting to a new dataset.
ArcGIS 9.1 Batch Define Coordinate System - This is a sample script-tool for Batch Definitions in version 9.1 only.

Workarounds for Datum Conversion in ArcGIS 9.x Projection Tools

Projection On-The-Fly and Data/Export Data... *** no workaround needed *** - In ArcGIS 9.x ArcMap you need to set the data frame transformation method if you have data layers in two or more different datums. Once you have done this (see Tips & Tricks Link above), both projection-on-the-fly and “Data/Export Data…” will perform the datum conversion correctly.
Project Tool Workarounds - The Project Tool may drop features if you are projecting to a geodatabase feature class. Here is what to do to work around this problem.
Batch Project Tool Workarounds - The Batch Project Tool has the same problem as the Project Tool. There are also a few other things you should know.
Project Raster Tool Step-By-Step Workaround - Raster projection is greatly enhanced in ArcGIS 9.x. If you are only reprojecting a raster from one projection to another, then no workaround is needed. If your reprojection requires a datum conversion, then you can use this workaround.