Circles are a nice symetrical shape, but they are very unlike property lines which tend to be angular, jagged, and haphazard- following topographical, political, and arbitrary boundaries. So if you start drawing circles all around the map around the center point of where some amateur cartographer has stuck an alleged school, your 1000 foot circle is not really representative of the actual gun free school zone. In fact, in most cases, it would be well short of the schools actual gun free zone or not correctly placed, depicting a gun free school zone hundreds of feet from where it should be.
The alternative then is to examine each school in the area and carefully plot 1000 feet from the boundary of the school grounds property line and make a map depicting the school zones taking into account that schools are all over the place and sometimes are not mentioned on commercial maps.
In either event, if you create, manage, and carry such a resource with you- you are establishing that you are aware of 626.9 and are aware of all the schools you have identified by encircling them and create for the authorities the evidence that they could use to charge and prosecute you under the pretense that you knew better when you happen to stray from your appointed path or happen to base your map on incorrect information.
It is easier for me, with my knowledge of my town, neighborhood and street to memorize locales that are 'gun safe' zones. This way I can transport in a locked secure case, then when I am at my destination, I would holster up and carry on foot. Once we can get a judge to recognize the private property exemption in 626.9, our options will open up and the only time we would be concerned about the school zone issue would be while driving or walking on public property and streets. (Which is ironic, because property that is owned by the people should be permissive of the Constitution...)
I forgot to mention 626.9(l)
With a license to carry, you can disregard the gun free school zones altogether.(l) This section does not apply to a duly appointed peace officer as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2, a full-time paid peace officer of another state or the federal government who is carrying out official duties while in California, any person summoned by any of these officers to assist in making arrests or preserving the peace while he or she is actuallyengaged in assisting the officer, a member of the military forces of this state or of the United States who is engaged in the performance of his or her duties, a person holding a valid license to carry the firearm pursuant to Article 3 (commencing with Section 12050) of Chapter 1 of Title 2of Part 4 , or an armored vehicle guard, engaged in the performance of his or her duties, as defined in subdivision (e) of Section 7521 of the Business and Professions Code.