1. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Geographic data Geographic data are categorized on the basis of a scaling system called “levels of measurement”. There are four levels of measurement.

2. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Nominal data: identification only, non-numerical Geographic levels of measurement Ordinal data: ranked, non-numerical Interval data: ranked on a standard scale where intervals between ranks are given in arbitrary standard units, e.g. Celsius temperature scale Ratio data: numerical with a known starting point

3. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Data Unit of measurement Level of measurement (Scale) Resort nameidentitynominal Resort rankingpositionordinal Average winter ºCinterval temperature Size of ski areasquare metresratio Table 2.1 in Heywood et al

4. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Nominal data are qualitative in nature. Ordinal data are ranked. Interval and Ratio data are quantitative. Map type or cartographic symbolization is linked to whether the data are qualitative or quantitative.

5. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl When data are qualitative, cartographic symbolization uses shape, colour hue, and pattern to differentiate features. The original of this chart and the charts on the following two slides are found at: http://atlas.gc.ca/site/english/learningresources/carto_corner/map_content_carto_symbology.html#3

6. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl When data are ranked, cartographic symbolization uses size or weight, colour value or intensity, and pattern to differentiate features.

7. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl When data are quantitative, cartographic symbolization uses size, thickness, and weight, colour value, and colour intensity to differentiate features.

8. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl ShapeAV Map optionsData characteristics point or line 1. single symbol 2. unique value 3. graduated symbol 1. no differentiation, base only 2. identification only, nominal data 3. ordinal, interval, or ratio variation in hue or symbol shape variation in size

9. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Shape point or line 4. graduated colour 5. chart 4. ordinal, interval, or ratio 5. interval, or ratio Data characteristics variation in colour value or intensity AV Map options

10. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl ShapeData characteristics polygon1. single symbol 2. unique value 3. graduated colour 1. no differentiation, base only 2. identification only, nominal data 3. ordinal, interval, or ratio variation in hue variation in colour value or intensity AV Map options

11. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl 4. dot 5. chart 4. ratio 5. interval, or ratio variation in unit quantity ShapeMap optionsData characteristics polygon

12. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl Most GISs include a DBMS which allows searches of the database and controls them. Then the users do not need to know how the data are physically stored and coded. Database management

13. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl DBMSs support retrieval functions in the form of queries. There are two general types of queries: 1. spatial queries: what is here? 2. attribute queries: where is this?

14. GEOG 2007A An Introduction to Geographic Information SystemsFall, 2004 C. Earl 1. spatial queries: what is here? query the map (View) 2. attribute queries: where is this? query the database (Table)