Key Terms Flashcards

Question

Types of Operators

Answer 1

Mathematical: Perform arithmetic operations. Boolean: Evaluate true or false conditions. Relational: Assess specific relational conditions (outputs true as 1, false as 0).

Answer 2

Tool allowing the use of maps in calculations, as rasters are composed of numbers.

Answer 3

Applied cell by cell, requiring both layers to be of the same size.

Answer 4

Applied from the perspective of each cell, affecting values across and down but not diagonally due to differing distances.

Answer 5

Change cell values based on their neighboring cells, such as calculating slope.

Answer 6

Subtracting one map from another reveals differences, useful for calculating changes such as temperature fluctuations on a planet.

Answer 7

Use the rastor calculator to find out if somehting is sutiable = it will change the map w colours output w t or f

Answer 8

Process of inputting values and deriving new output values. Involves replacing input values with new raster cell values. Often used to simplify or alter the interpretation of existing raster data. Can be applied to both raster and vector data. Simplifies or classifies results, serving as an answer to a query. Example: Creating a table in Excel and inputting values for reclassification.

Answer 9

For more complicated statisitics Useful for many classes in one feature file (when it is practically not possible to manually classify into groups). Typically used for raster Requires classification schemes (algorithms or mathematical formula) which will combine various classes into a single group.

Answer 10

data presented in a different way that can cause different results Equal-interval Classification Natural Breaks Classification Quantile Classification all three methods give different interpretations without corrupting the data

Answer 11

A data classification method that divides a set of attribute values into groups that contain an equal range of values. = more intuitive but ‘ doesnt respect the data’

Answer 12

A method of data classification that partitions data into classes based on natural groups in the data distribution. Natural breaks occur in the histogram at the low points of valleys. = harder to communicate but better for statisitics

Answer 13

A data classification method that distributes a set of values into groups that contain an equal number of values. = uses the data with fixed intervals but the intervals are based on the number of values within that class

Answer 14

Classifying vector data involves assigning various symbols to features (different objects within the same layer) based on their attributes. This makes it easy for map users to visually understand the attributes of different features.

Answer 15

Analyzing the relationships between an entity and its surrounding entities or attributes involves examining how one entity is related to others nearby. This is crucial because many questions rely not only on what exists at a specific location but also on what surrounds that location. A common and effective method for analyzing these relationships is by using spatial analysis techniques.

Answer 16

A zone constructed outward from an object (point or line) to a specific distance (user defined)

Answer 17

Definition: A zone inside a polygon constructed a fixed distance from the edge. It's a zone within the buffer area. Buffers may sometimes overlap, but data from only one singular buffer is typically needed. Each buffer represents one row; when connected, the lines dissolve together. Often simplifies processes, such as in the butterfly project. Important note: Once intersections are dissolved, this action cannot be undone.

Answer 18

Neighborhood operations are commonly used for data simplification on raster datasets. An analysis that averages neighborhood values would result in a smoothed output raster with dampened highs and lows as the influence of the outlying data values are reduced by the averaging process.

Answer 19

Change a value based on its neighboring cells Neighbourhood Statistics is a focal function that computes an output raster where the value at each location is a function of the input cells in a specified neighbourhood of the location. Borning for one cell but useful when changing more than one cell

Answer 20

Definition: A grid pattern that processes each cell in a raster dataset by shifting across the dataset. Usefulness: It's handy for calculating local statistics, detecting edges, and smoothing data. Smoothing Effect: It smooths data by averaging and reducing random noise. Impact of Window Size: Larger windows make data coarser and increase smoothing. Manipulation: It allows adjusting map appearance without compromising statistics, letting you confirm or challenge certain phenomena.

Answer 21

removes the randomess when smoothing data

Answer 22

difference between the smoothed map from the original making it a map of the noice – useful for seeing if the sensor is working correctly

Answer 23

Definition: Utilize Digital Elevation Models (DEMs) to depict slope (inclination), aspect, and hillshading. Methodology: These functions are typical neighborhood processes, where each pixel in the resultant layer is influenced by its own elevation value as well as those of its surrounding neighbors. Characteristic: Essentially, they apply neighborhood functions on top of elevation models to generate information about slope, aspect, and hillshading.

Answer 24

DTM – ground surface with nothing else DSM – is the ground and building with it = rastor can be both = Vector triangular irregular network – different kind of digital elevation model

Answer 25

The Slope tool measures the steepest slope between each cell by considering the values of its eight neighboring cells within a 3x3 window.

Answer 26

Neighborhood analysis as well The angle the slope is facing The aspect tool calculates the compass direction that a topographic slope faces, with the aspect value for each cell in the raster calculated using an algorithm that incorporates the values of the cells eight neighbours (3 x 3 window) – usually measure in degrees. Based on its neighbor it will respond based on the way that it is facing

Answer 27

The hypothetical illumination of a surface according to a specified azimuth and altitude for the sun, which creates a three-dimensional effect that provides a sense of visual (shaded) relief Just changes the way that we look at the map Not statisical analysis We create a fake sun and the shading is based on its neighbor A good way of communicating a map without color

Answer 28

The viewshed analysis tool is useful when you want to know, for example, what can be seen from one or more points. It tells you what you can and cannot see based on where a person is standing

Answer 29

Where we have gaps in out knowledge = e.g. a satelitte is trying to take a photo but there is a cloud = it makes a guess on whats missing and tries to fill in the wholes

Answer 30

Going beyond the data to guess the future

Answer 31

Using google maps to find out how far and how long it will take us to get from A to B Can factor in traffic , road network and other layers can be included

Answer 32

(e.g. tree, roads, habitat) can be described in terms of points, polylines and/or polygons (area). Non-spatial data (data without inherently spatial qualities such as a description) or attributes have to be stored in a tabular format, linked to these entities.

Answer 33

provide information and/or description of spatial entity (e.g. point = tree, polyline = road, and polygon = grass field) . - classes as a common thing – something that all the entities have in common

Answer 34

the same thing as a colum on a table - something that all the entities will have in common

Answer 35

The table controls how we change the symbol

Answer 36

Whatever is in the value of the cell Rastor calculator to extract attributes

Answer 37

Can join tables to make more complicated queries The nature of the queries you can make is based on the relationship

Answer 38

In QGIS LAYERS can come in many filetypes but the most common are vector shapefiles and raster Tiffs. The style (display) of a layer is set manually or via an imported style guide. The style settings will be lost if you open the layer in a new project or transfer the file to another person…..but you could save the style setting and transfer that too

Answer 39

Raster layers, such as IMG, GEOTIFF, and TIFF, utilize a grid-cell data structure where the geographic area is divided into cells identified by rows and columns. Note that raster data layers created within GIS are usually, but not always, permanent. IMG files may reduce file size but may also result in data loss, which is why TIFF is typically preferred.

Answer 40

Shapefiles (*.shp) are used to store the geometric location, shape, and attributes of VECTOR features. A shapefile comprises a set of related files and can accommodate only one feature class, which could be a point, polyline, or polygon. MANDATORY FILES: *.shp: Contains the feature geometry. *.shx: Serves as a positional index of the feature geometry. *.dbf: Stores columnar attributes of each entity in dBase IV format, directly openable in software like Excel. These files are essential for the shapefile to function as a complete dataset. OTHER FILES (12 in total): *.prj: Provides projection information and the coordinate system. These are supplementary files for additional data. Remember: A shapefile can consist of a maximum of 15 files. Changing a layer in the browser automatically updates related files. When sharing a layer, ensure to include all associated file formats from the browser.

Answer 41

In GIS, a hierarchical system refers to the organization of geographic data into layers or levels based on their scale or detail: Base Layers: Provide general features covering large areas. Intermediate Layers: Offer medium-level detail for specific regions. Top Layers: Provide the highest level of detail for specific features in smaller areas. This structure allows for efficient data management and analysis at different scales or levels of specificity in GIS.

Answer 42

In GIS, a root folder refers to the main directory where GIS data, projects, and related files are stored. It serves as the starting point for accessing and managing GIS data and workflows.

Answer 43

In GIS, a relational system refers to a database management approach where data is organized and stored in tables that are related to each other based on common attributes. This model allows for efficient management, querying, and analysis of spatial and attribute data

Answer 44

A function that combines the attributes in two layers based on distance (one feature closest to another) or containment (one feature inside another)

Answer 45

Merge' combines two or more raster layers, such as merging 100 aerial photos into a single layer. Similarly, 'Merge vector layers' combines multiple vector layers of the same type. Note that 'Explode lines' performs the opposite action by breaking apart connected lines into separate entities.

Answer 46

Summary statistics can be obtained with the "purple E thing" in GIS, similar to summary functions in R. This tool allows users to calculate statistics such as mean, median, sum, minimum, maximum, standard deviation, and count for attribute data associated with geographic features.