3Steven M Frank, Michael F. GoodChild, Harlan J Onstrud, Jeffrey K Pinto. Framework Data Sets for the NSDI, 1995: 15-16.http: //www. ncgia. ucsb. edu/Publications/Tech_Reports/95/95 - 1. pdf
4Wulan. Methodology for Selection of Framework DataCase Study for NSDI in China [D]. Master Thesis, ITC, 2002.
7Section on Survey Research Methods. American Statis tical Association. Designing a Questionnaire [ M ]. Alexandria: American Statistical Association, 2002.
8Ellen Taylor-Powell. Questionnaire Design: Asking questions with a purpose [ M ]. Madison: Cooperative Extension Publications, 1998.