(Note: the Projector extension in ArcView 3.1 and lower cannot be used to convert between the NAD27 datum and the NAD83 datum)

ArcView comes with a number of extensions that are basically samples of how one can customize and extend ArcView's capabilities.  One of these extensions is called Projector and allows you to project a theme or coverage into a new projection system.  The result is a new shape file in the new projection. To use this extension, you must know what the current projection and map units of the theme you want to re-project.   For Arc/Info coverages, information about a projection can be often be found in the prj.adf file under the in the coverage subdirectory.  You can view this file with a text editor like Wordpad, but not in ArcView (go figure....). Other places to look for projection information include any readme.txt or similar files that come with the data set. (Note: use this Projector extenion to create new projections, not the View-Properties dialog box in ArcView - the latter only works with decimal degree datasets and creates a temporarily projected view.)

To use the Projector extension, you must first have it loaded as an extension.  Choose File-Extensions and look for the Projector extension. Checkmark it if you find it  and press OK to add it to your extensions in ArcView.  If you don't find it in the list, you need to copy the prjctr.avx file from the c:\esri\av_gis30\arcview\samples\ext\ directory into the c:\esri\av_gis30\arcview\ext32 directory.  Then check for the Projector extension in ArcView again - it should appear.

Once the extension is loaded, the Projector icon should appear as part of your View menu in ArcView -

To use the Projector, do the following:

1. Bring up the theme you want to project to a new projection (e.g., rivers) in a new view (not in the same view as your other data).
2. Make that theme the active theme
3. Set the View-Properties map units (the map units must be set to the units of the theme's existing projection)
4. Click on the Projector icon
5. You will be asked for the Input Projection - this is the current projection of the theme. For a standard projection, choose a category and then a type (e.g., State Plane 1927 as category, Texas Central as type). For customized projections, see the note below. (Note: if the theme you are projecting is in decimal degrees, you will not be asked for an input projection.  ArcView will know that this data is in decimal degrees already and the only projection you are asked to define is the new projection)
6. You will then be prompted for output units - you must choose the unit of the coordinate system into which you are projecting (e.g., if you are converting from UTM Zone 14 meters to Texas Central State Plane  feet, you must choose feet, or the new theme will not show up with other themes in the State Plane feet coordinate system)
7. The next dialog box simply says "Projection Properties" - here you select what you want for the new projection (again, category and type)
8. Press OK - you are then asked if you want to have the program recalculate area, perimeter and length values based on your selected output units.  Choose yes.
9. You are then asked if you want to add the newly projected shape file to the view.  You can choose Yes, but make sure you add it to a NEW view - because it is a new projection, it cannot be seen together with the old theme.
10. In the next dialog box, choose a directory location and new name for the new shape file - it's a good idea to include something about the projection in the name so you don't forget what projection it is (e.g., rivers-utm.shp)
11. Press OK and the re-projection begins.  The result will be the shape file you specified.

Specifying custom projections

ArcView has a list of standard projections that it can handle.  Some projections, like the Texas State Mapping System, are customized to fit a cartographer's needs better.  The Texas State Mapping System uses a Lambert Conformal Conic projection with parameters specific to Texas in order to create maps of the entire state in such a way that distortion is minimized.  Ideally all Texas state agencies will use this Texas  State Mapping System, allowing data layers from different agencies to be combined. (In the past, each agency used a different projection system.)

The following gives all the information you need to create a custom Texas State Mapping System projection in ArcView, either as an input projection (say you downloaded a coverage from TNRIS and want to convert it from the Texas State Mapping System into latitude and longitude in order to view it with federal data for Texas in the latter format) or as an output projection (you want to convert latitude/longitude layers into the Texas State Mapping System).

Important! The latitude/longitude information above is in degrees and minutes;  ArcView Projector requires information in decimal degrees. Recalculate degree minutes into decimal degrees before you start.  E.g., 27 degrees, 25 minutes = 27 degrees, 25/60 minutes = 27.416667 decimal degrees.

• Projection: Lambert Conformal Conic
• Ellipsoid: Clarke 1866
• Datum: North American 1927
• Longitude of Origin (also called Central Meridian): 100 degrees west (-100)
• Latitude of Origin (also called Reference Latitude): 31 degrees 10 minutes north
• Standard Parallel # 1: 27 degrees 25 minutes north lat.
• Standard Parallel # 2: 34 degrees 55 minutes north lat.
• False Easting: 3,000,000 feet
• False Northing: 3,000,000 feet
• Unit of Measure: feet (international)

11 October1998
The School of Architecture at UT Austin
Comments to: Barbara Parmenter