Chapter 4 - Maps, Data Entry, Editing & Output Flashcards
Building a GIS database needs these two elements
Spatial data and many coordinates
What are the two types of data used to build GIS databases?
Hardcopy and digital data
This was the form of all spatial data before 1960
Hardcopy
These maps date from the mid-1900s
Cartometric maps
Is hardcopy data scarce?
No
What are three examples of hardcopy data that can be used to build a GIS database?
Paper maps, photos, legal records
This type of data is in computer compatible form
Digital data
Can digital data be stored in hardcopy?
Yes
What are the two common types of hardcopy maps?
Feature and thematic maps
This type of hardcopy map displays one or more features such as roads, streams, boundaries and cities
Feature map
What is another name for feature maps?
Reference maps
This type of hardcopy map displays spatial patterns of attributes
Thematic map
What are two things that thematic maps use to display spatial patterns of attributes?
Color shading or symbology
What are three of four different types of thematic maps?
- Choropleth maps; 2. Dot density maps; 3. Isopleth maps; 4. Proportional symbol map
These thematic maps use shading to represent attribute values
Choropleth maps
These thematic maps use dots to represent attribute values
Dot density maps
These thematic maps use lines to connect attributes of equal values
Isopleth maps
These thematic maps scale symbols to attribute values
Proportional symbol maps
What is another name for proportional symbol maps?
Graduated symbol maps
What are four properties of hardcopy maps?
- Map elements; 2. Coordinate lines; 3. Scale; 4. Map media
What are five of eight elements of hardcopy maps?
- Data plane; 2. Scale bar; 3. Title; 4. Legend; 5. Neatline; 6. Cartographer name; 7. North arrow; 8. Date
What are two types of coordinate lines that can be used on hardcopy maps?
Lat-long or x-y coordinates
This is the relation between a map unit and a related distance on the ground
Scale
These maps cover a large area with lower detail
Small scale maps
These maps cover a small area with higher detail
Large scale map
What are three ways to report scale on a map?
Verbally, as a ratio, or as a scale bar
Most maps are printed on this
Paper
Paper maps can shrink and swell with changes in this
Humidity
What are two rarer materials for maps to be printed on?
Vellum and film
Media alterations on hardcopy maps can distort these
Map features
What are two spatial issues that can arise with hardcopy maps?
Map generalizations and boundary discontinuities
These address approximations made during map creation
Map generalizations
Map generalizations can be a source of these
Errors
These often occur at map edges
Boundary discontinuities
Boundary discontinuities arise due to differences in these three things
- Time of data collection; 2. Map interpreters; 3. Coordinate registration
This process converts map and image data into digital coordinates
Digitization
What are two types of digitization?
Manual and automated digitization
In this type of digitization, human users draw features
Manual digitizing
This type of error arises with decreasing map scale in manual digitization
Positional error
Humans can interpret this type of map and correct errors during data capture
Deteriorated maps
Manual digitization results depend on these two things
Equipment and operator experience
What are two sources of inconsistency in manual digitization?
Different operators and fatigue
Is the manual digitization process slow and labor intensive?
Yes
Does manual digitization cost more than automated scanners?
No
What are the two types of manual digitization?
Hardcopy and onscreen digitization
What is another term for hardcopy digitization?
Heads-down digitization
In this type of manual digitization, hardcopy is secured to a digitizing table and traces with a puck
Hardcopy digitization
This form of manual digitization produces the most operator fatigue
Hardcopy digitization
This form of manual digitization needs costly equipment and trained operators
Hardcopy digitization
What is another term for onscreen digitization?
Heads-up digitizing
In this type of manual digitization, hardcopy is scanned into raster format
Onscreen digitization
In this type of manual digitization, features are traced on a computer screen with a mouse
Onscreen digitization
What is the more precise type of manual digitization?
Onscreen digitization
Digitizing software uses this process to reduce errors in manual digitization
Snapping
This function creates smooth curves through points during manual digitization
Spline function
This process removes unnecessary vertices in manual digitization
Line thinning
This type of digitization uses a scanner or other device to digitize hardcopy data
Automated digitizing
This type of digitization saves input time but often needs heavy editing
Automated digitizing
What are two types of automated digitization?
Scan digitization and automated vectorization
In this type of automated digitization, a scanner records hardcopy into raster format
Scan digitization
Scan digitization works best with this kind of hardcopy
Pristine hardcopy
This type of automated digitization can work with single feature and without text
Scan digitization
In this type of automated digitization, a computer creates vector data from hardcopy
Automated vectorization
In automated digitization, this process reduces width of raster linear features
Skeletonizing
This describes the assignment of coordinates to a scanned image
Image georeferencing
What is another term for image georeferencing?
Image registration
Image georeferencing enables a scanned image to align with this
Existing layers in GIS
The image georeferencing process requires these
Control points
In image georeferencing, control points are these with known lat-long coordinates
Ground features
What are the four steps to georeferencing a digital image?
- Identify control points on an image; 2. Determine lat-long coordinates for control points; 3. Fit registration model equations using control points; 4. Transform scanned image using fitted equations
In georeferencing an image, these must be common to the image and the ground
Control points
In georeferencing an image, these must be clear and unambiguous
Control points
These types of features make good control points in georeferencing an image
Permanent, well-defined features
These make good control points in image georeferencing
Benchmarks
Equations relate digitized coordinates to these
Lat-long values
What are two kinds of image georeferencing equations?
Affine transformation and higher ordered polynomial
This type of image georeferencing equation requires a minimum of 4 control points (18-30 optimal)
Affine transformation
This type of image georeferencing equation requires more control points and often produces a poorer fit
Higher ordered polynomial
In raster resampling, a GIS project may include many of these
Different raster layers
Layers may differ in these two aspects
Cell size and x-y orientation
Analysis of multiple raster layers may need this
Alignment of raster cells
Raster resampling takes an input raster layer and creates this
An output raster layer with different configuration
What are two types of raster resampling?
Nearest neighbor and interpolation
In this type of raster resampling, an output cell is given the value of the nearest source cell
Nearest neighbor
What is nearest neighbor raster resampling ideal for?
Classified images
Do class values change for images in nearest neighbor raster resampling?
No
In this type of raster resampling, output value is a weighted average of a cell neighborhood
Interpolation
What is the purpose of a map?
To communicate spatial information
What are four things that map design must consider?
- Intended audience; 2. Information to communicate; 3. Area of interest; 4. Physical/resource limitations
What are seven map design decisions to consider?
- Scale/size/shape; 2. Data to plot; 3. Symbol shapes/sizes/patterns; 4. Labeling properties; 5. Legend properties/borders; 6. Layout/proportion; 7. Projection/datum info
What are the two components of digital data?
Data and metadata
GIS software contains utilities for this
Data import/export
The long history of GIS has led to many of these
Different data formats
This was established in 1992 to easily transfer data between platforms
Spatial data transfer standard
This is data about data
Metadata
What are seven considerations when transferring digital data?
- Identification; 2. Data quality; 3. Spatial data organization; 4. Spatial reference; 5. Entity/attribute; 6. Distribution; 7. Metadata