To Add X Y Z co-ordinates to point shapefile

1. Create a point shapefile and add points to it.
2. Add created shape file in Arcmap.
3. Open its attribute table.
4. Add field – given name and select double as its Format.
5. Right click on the added Field and select Calculate geometry
6. Select in the given field X-co-ordinate or y-co-ordinate as desired.
7. Repeat for second coordinate
8. To add Z-co-ordinate you need DEM of that area; add DEM to Arcmap
9. Use extract values to point tool in spatial analyst tool to add Z-co-ordinate
10. Select input raster as DEM.

Creating a New Point shapefile in ArcGIS 9.3

1. Start Arc Catalogue
2. Move to folder where you want to create shape file
3. Right click in that folder and select New shapefile
4. Feature type “point”
5. Edit –Coordinate system
6. Select appropriate Geographic or/and Co-ordinate
7. Move to Arc-map and add created shape file  in Arc-map
8. Start Editor
9. Use sketch tool to create points
10. Save and stop Editor.

How to create and project a Point shapefile from XY coordinates using from dbf or Excel files

Creating shape file from points in GIS

1. use Excel 2003 or earlier to create a dbf III file .dbf format
2. Keep one sheet only. remove all the remaining sheets
3. give labels in first row for longitudes and Latitudes in first two columns 
4. Type  data  in two columns X and Y  in decimal degrees
5. save file as dbfIII format as filename.dbf
6. open filename.dbf file in Arcmap
7. Display XY data in arcmap by right clicling on the file 
8. select label for X for longitudes and Y for Latitudes field
9. give only geographic coordinate systems of the points
10. Project the file using project tools located in data management and feature project tools in arcgis 9.3 
11. export the projected file 

To Use directly Excel file  see the reference below


Follow the below instructions to turn an Excel file containing latitude/longitude

coordinates into a Shapefile using ArcMap.



Open ArcMap.

1. Add your Excel worksheet (97-2003 or 2007) to ArcMap 9.3 just as you would spatial data,
2. Filename.xls(x) will appear in the table of contents (TOC). Right-click on the worksheet
3. name in the TOC, and choose "Display XY Data..."
4. In the dialog box, the X Field should be Longitude and the Y Field should be Latitude.
5. If you know the spatial reference of the input coordinates, click the "Edit..." button and
6. select it.
7. For example, if your coordinates are based on a WGS84 Geographic Coordinate System, Click
8. the "Edit..." button, then the "Select..." button, Geographic Coordinate Systems 
9. If you do not select a spatial reference, the shapefile will have an Unknown Coordinate System.
10. Click OK.
11. The coordinates should plot as a point event theme. Note that it is not a shapefile, just an event theme. To create a shapefile from the event theme, right-click the layer in the TOC and select Data and  Export Data... Then select a location for the new shapefile, name it and click OK.
12. TIP: Make sure that coordinates South of the Equator and West of the Prime Meridian arenegative, or your points will plot in the wrong hemisphere!

Reference

http://www.lib.unc.edu/reference/gis/faq/xy.html

Latitude and Longitude

Latitude is the angular distance from the Earth’s equator and is expressed as either north or south. Longitude is the angular distance from the Greenwich meridian and is expressed as east or west.

Latitude 

The largest latitude circle is the equator itself, which is zero degrees. Other latitude circles are parallel to the equatorial plane, and grow smaller nearer the poles. You can imagine a toy with bottom most ring as equator (Figure 1). The earth is divided into two hemispheres : Northern and Southern . The northern circles are marked as 0º to 90 º N and southern circles are marked 0 an 0º to 90 º S. All the circles are parallel to each other so these are sometimes referred to as parallels (Figure 2)

Figure 1 Toy with rings of reducing   diameter

Figure 2 Latitude  measurement (http://homepage.mac.com/kvmagruder/bcp/sphere/terreslat.htm)

Longitude 

Longitude circles are not parallel to each other, but pass through both poles and intersect the equator perpendicularly. All longitude circles are great circles of equal diameter. The prime meridian, which equals zero degrees longitude, is the longitude arc from the North pole to the South pole that runs through Greenwich Observatory in England. The longitude arc 180 degrees opposite (the other half of the same great circle) is the international dateline. Longitudes are measured in degrees east or west of the Greenwich meridian (Figure 3).

Figure 3 Longitude measurement (http://www.physics.miami.edu/huerta/class/110/110_gif/LATITUDE_LONGITUDE_MERIDIA.GIF