How do I get started using GIS at Harvard School of Public Health?

Harvard University has a site license for ESRI software. Click on the above link to the site license information and follow the directions for downloading and installing the software and connecting to the license server. Countway Library covers the cost of the site license for the Longwood Medical Area faculties. Harvard faculty, students and staff can run ESRI software on Harvard network computers at no charge. If you have the space on your computer I recommend installing the ArcGIS 8.3 Workstation version (ARC/INFO). Since the interface for the workstation and desktop versions are the same and there is no additional cost under the site license, you might as well get the additional tools available with the workstation version in case you need them later.

Make sure you also download the books and maps, and take a look at some of the books for tips on how to get started. (For example "Getting Started with ArcMap"). The tutorial data you can download during the installation is designed to be used with the books.

Refer to the site license web page link to Tech Support, Training and Hard Copy Documentation for information about free access to the ESRI Virtual Campus for online training. The ArcGIS online help is actually pretty useful and the ESRI web site knowledge base is extremely helpful.

What happens if the Harvard ESRI license server goes down while I am running ArcGIS?
Here's a tip Bonnie Burns from the Harvard Map Library posted to the Harvard GIS Users ABCD Group:
> There is a bug in ArcGIS 8.3 (shocking!). Anyway, this
> particular beastie will keep the desktop administrator
> from opening if the license server it points to is down.
> I got a message that esri-lm was down, tried to change
> to mercator, and my Desktop admin didn't start. And I got
> crabby. Then I got over it. The solution is listed here:
> http://support.esri.com/index.cfm
> Article Number: 24775 (You will need to log on to the ESRI site, but it is free)

Where do I find data?

There are numerous sources of free data available through the internet. It is also possible to purchase data from various vendors. I have found government agencies to be very willing to provide data to academic researchers at no cost, although it sometimes takes some detective work to find the right person with access to the data you want.

In Massachusetts MassGIS is a tremendous resource. ESRI's Geography Network is a good place to start looking for data from around the world. Check out the Harvard Geospatial Library for electronic data available at the university. For additional sources of data refer to Links.

How do I get longitudes and latitudes (or other x and y coordinates) from a spatial dataset?

Frequently researchers want to know the coordinates of geocoded points in order to analyze the data with a statistical model. To get the coordinates in the coordinate system of the dataframe (map) in use:
-Open the attribute table
-Add two new fields for x-coordinate and y-coordinate. I usually use double for the field type
-Go to the Editor toolbar and start editing the point layer. You may need to go to View, Toolbars in order to see the Editor toolbar.
-Right click on the new x-coordinate field and choose Calculate Values
-Load the script xcoord.cal and click on OK
-Repeat for the y-coordinate field, changing the x's to y's in the xcoord.cal script.
-Save your edits and stop editing
-You can export the attribute table, or if you are working with shapefiles, the .dbf file will now contain the coordinates.

How do I find the centroid of a polygon?