----------------------------Original message---------------------------- Greetings, The United Nations Environment Program's Global Resource Information Database in Arendal, Norway (UNEP/GRID-Arendal) along with the Department of Surveying at the Agricultural University of Norway have initiated a project to examine data quality issues for spatial databases. Specifically, these issues will be examined for one of the world's most comprehensive and detailed GIS databases, the 1:1 million Digital Chart of the World (DCW). One of our tasks is to review and summarize present use, experiences, and quality assessments that have been carried out on the DCW and its base map material. In support of this effort we are asking the GIS and Remote Sensing community to provide some information on their experiences with the DCW. To encourage users to respond, we have provided a short questionnaire for DCW users to complete. Our project will be completed in August, 1995, at which time we will make our report available to the public. Also, we will forward a copy of our report through the post to each individual that submits information on their experiences with DCW data. More details on our project are provided after the questionnaire. Thanks in advance for your time and efforts. (Christopher G. Smith) PLEASE REPOND DIRECTLY TO: [log in to unmask] QUESTIONS: 1. Please provide your name, address, phone, and email. 2. Briefly describe your particular use of the DCW data. 3. Which geographic region(s) do you use DCW data? 4. Which layer(s) of the DCW are you using? 5. Which software package do you use to work with the DCW data? 6. Did you experience problems with the quality of the data? (Y/N) If yes, briefly describe your problems. 7. Are you willing to provide further information concerning the quality of these data? (Y/N) PROJECT TITLE: Issues of Error, Quality, and Integrity of Digital Geographic Data: The Case of the Digital Chart of the World RESPONSIBLE PERSONNEL: Langaas, S.(1), Tveite, H.(2), Baxendale, H.J.(3), and Smith, C.G.(3) (1) UNEP/GRID-Arendal c/o Dept. of Ecology, Stockholm University, S-10691 Stockholm, Sweden. (2) Dept. of Surveying (ILM), Agricultural University of Norway (NLH), P.O. Box 5034, N-1432 As, Norway. (3) UNEP/GRID-Arendal Longum Park, P.O. Box 1602, Myrene, N-4801, Arendal, Norway. Phone: +47 37 03 56 50 Fax: +47 37 03 50 50 PROJECT SUMMARY: This project will examine the concepts of accuracy, error and integrity as applied to spatial databases, and specifically relate this examination to the world's most comprehensive and detailed 'public domain' GIS database, the Digital Chart of the World (DCW) with nominal scale of 1:1million. Four interrelated tasks will be accomplished during the study: (1) To theoretically examine the issues of accuracy and integrity of spatial databases and recommend assessment techniques. (2) To provide a comprehensive summary of the documentation that describes the lineage of the data set, covering the entire process from image interpretation to final CD-ROM structuring. (3) To review and summarise present use, experiences, and quality assessments that have been carried out on the DCW and its base map material. (4) To quantitatively perform quality assessments of the DCW on selected regions using other georeferenced data sets with higher known accuracy. The anticipated beneficiaries of the project will be: (1) The GIS community, both data producers and users, both practitioners and academicians, concerned with quality aspects of georeferenced data. (2) All users of DCW data. +------------------------------------------+----------------------+ | Christopher G. Smith [[log in to unmask]] | +---+---+---+---+ | | Systems Analyst | | G | R | I | D | | | GRID - ARENDAL | +---+---+---+---+ | | P.O Box 1602, Myrene | UNEP/GRID | | N-4801 Arendal, Norway | Global Resource | | Phone: +47-370-35650; Fax: +47-370-35050 | Information Database | +------------------------------------------+----------------------+