Mapping GIS Data & Data Management Flashcards
What do we mean by the terms “convention” and “connotation” when making maps?
convention: how things are usually done
connotation: what emotions your symbols convey
how would you visually alter a change in category on a map? change is quanity?
category: vary shape, line type, pattern, color, font
quantity: vary size, thickness, color
what is the HSV color model and how is it useful on a map?
-vary hues for changes in category (i.e. shade)
-vary saturation (i.e. intensity) and/or value (light or dark) for changes in quantity
what are the map types of data that you will encounter, and what are the appropriate maps we can make with each data type?
nominal data: names or uniquely identifies objects / e.g. state names, parcel ID number / SINGLE SYMBOL MAPS
categorical data: place features/feature classes into defined number of distinct categories / e.g. highway classes, landcover types / UNIQUE VALUES MAP
ordinal data: type of categorical data
ranks categories along an arbitrary scale / e.g. Grades: A,B,C,D,F or low, medium, high slope / UNIQUE VALUES MAP
numeric data: interval and ratio data must be divided into classes before mapping. mapped using variations in symbol size, thickness, or saturation/value / QUANTITIES MAPS (graduated color, graduated symbol, dot density)
what is a classed map? what are some of the ways we can classify data?
maps with classes like graduated color map (choropleth map) and graduated symbol map
what is MAUP? How do we account for MAUP when making maps?
mapped units that are larger will tend to have larger values because they take up more space. we can account for MAUP by normalizing our data (e.g. normalize # of whatever by area of the state)
what is a raster stretch? why might it be useful when mapping with rasters?
a raster stretch is when the values are placed in a gradient. COME BACK TO THIS ONE
what is the difference between a standalone (source) table and an attribute (destination) table?
Attribute table: stores attributes of map fts. associated with a spatial data layer. has special fields for spatial information. FID (shapefile), OBJ (if in a geodatabase) DESTINATION
Standalone table: stores any tabular data. not associated with spatial data. cannot be a destination table. contains OID, or OBJECTID in geodatabase SOURCE
what is cardinality? how do we assess the cardinality of a join?
Cardinality is how many join records match the target record. destination on the left, source on the right
-one to one (states to governors/ countries to capitals)
-one to many (states to cities/districts to schools)
-many to one (cities to states/ schools to districts)
-many to many (students to classes / stores to customers)
what is the rule of joining tables?
each record in the destination table must match one and only one record in the source table
what is meant by the term “logical consistency?” when might it be necessary to edit shapefiles?
logical consistency measures how well features in the data set mimic the relationships of features in the real world
-to avoid dangles (where two lines fail to connect)
when entering an edit session, why is it important to save often?
editing can sometimes corrupt map files
