Data Analysis Vector Flashcards
What is nontopological analysis
This is when the spatial relationships between geographic features is not modeled or required.
In vector geo data processing there are three main phases the first one being input functions , name what the subcategories under inpUt functions and define them .
Table digitization: this is manually entering geographic coordinates and attributes into a database.
Importing : bringing external digital data into the GIS database.
Image scanning : converting physical maps /documents into digital format using a scanner
In vector geo data processing there are three main phases the first one being analysi functions , name what the subcategories under analysis functions and define them .
Analysis functions can be divided into two main areas topological and non topological functions
In vector geo data processing there are three main phases the first one being analysi functions , define the subcategories under topological analysis.
Topological analysis : has two main subcategories:
Feature based analysis ; this has functions like feature overlay analysis ( combining multiple layers to determine relationship between features. Another function is buffering : where a zone is created around features at a specified distance.
The second subcategory is layer based analysis : this is also has the function of layer based overlay analysis , where different thematic layers are measured to analyse relationship between them.
There is also the net work analysis: where interconnected pathways are analyzed to determine the connectivity(finding the shortest path way for emergency services).
There function is reclassification, which is assigning new categories to existing values of data based on specific criteria.
In vector geo data processing there are three main phases the first one being analysi functions , define the subcategories under nontopological analysis.
This has the following analysis functions:
Address geocoding : converting address into geographic coordinates.
Statistical computation: performing statistical analysis on spatial data attributes.
Attribute database query: retrieving specific data based on specific attribute criteria.
Area calculation: measuring size of geographical features.
In vector geo data processing there are three main phases the first one being output functions , define the subcategories under this function.
Vector based composition : creating maps and assembling vector data layers.
Vector-raster conversion : transforming vector data( points, lines , polygons) into raster format.
True or false : long or short refers to space needed to store numbers.
True
What is the difference between an integer and a double
Integer represents whole numbers without decimal points .
Double represents double precision floating numbers allowing fractional values .
Why is understanding the distinction between an integer and a double important?
These two are important to understand because they are crucial for accurate data representation and storage efficiency.
What is the difference between selection by location and selection by attributes.
Select by attributes : selects /finds features in your data that match specific criteria or values.
Select by location : finds features based on their geographic location relative to other features..
What are some operators for attribute based data query.
EQ(=): equal to
NE: not equal to
LE(<=)
LT(<)
GT(>)
GE(>=)
What does reclassifying a table influence, in terms of reducing or increasing classes.
It influences the way data is interpreted and grouped. Reducing can make data simple and easier to understand but in some cases can lead to loss of data .
Increasing can lead to enhance details in data sets but can lead increased complexity.
True or false: there is a tool called calculate geometry located where the field calculator is in the attribute table that can help with geometric calculation .
True
What are spatial calculations.
These are calculations performed as an intermediate step to obtain attribute data for certain tasks. Provide additional attribute data .
How do you do access the geometric and field calculator.
Open attribute table , right click on a column a drop down appears with both options .
In geometry you can pick to calculate area, perimeter,or x or y coordinates of centroid.
Why is buffering done
It helps with understanding surroundings : through identifying and understanding what is around a location.
Can help delineate an area for protection , study focus , or identify hazardous risks.
True or false : buffer zones are always polygons but can be used in both raster and vector mode .f
True.
How will buffering be done on say if the city wants to regulate the liquor stores in school areas
After adding necessary layers , use select by attribute feature to highlight the schools that are needed.
Then access the buffers tool by clicking the editor menu and choosing buffer from the drop down options . T
Then specify buffer parameter : in the buffer dialog box specify desired distance, choose appropriate units . Decide on if it will be a single or merged buffer and click ok to create buffers .
Map overlay facts
Integrates two data sets
Is a layer based topological operation.
Here features of two layers are intersected to create new output features .
Everything that is a transformation creates new data , name some of these transformation functions
Buffering
Map overlay
Reclassification
True or false: different types of overlay possible depending on point, line, polygon
True
What does dissolve do ?
Combines adjacent features that share similar attribute values into a single feature removing internal boundaries.
What is merge
This combines multiple datasets (usually layers) with the same geometry ( points, line polygons) into a single data set, while still maintains original boundaries and features.
How to dissolve :
After all layers and dataset has been added ,:
Go to analysis tab and click on geoprocessing toolbox , in there you can search for and select dissolve tool , set the appropriate input features to desired data set , specify the fields to be dissolved, and run .
How to merge
After loading in layers and data sets , go to analysis table, open the geoproces pane /toolbox, search and click on the merge tool, set the input datasets you want merged , set the output data set where the merged data will be stored, map the field from input to output data sets as required and then run .
What is function of descriptive summaries ?
To reduce complexity in data , get an overview .
Usually answers questions like how was the weather in Sweden like last summer.
True or false : a histogram is a two dimensional plot of attribute values grouped together by magnitude and frequency of records.
True
True or false: statistics on attributes do not contain location
True .
What are centroids
These can also be called mean center: it is the average location of a set of points
What does a central feature in the geoprocessing tool box pane do?
It locates the most centrally located feature in a points, polygon or line feature class.
What does a mean center feature in the geoprocessing tool box pane do?
It computes or contains the average x and y coordinates of all features in the study area. Useful for tracking changes in distribution or for comparing distributions of different types of features.
