Comprehensive GPS, Raster Analysis, and Spatial Interpolation Concepts

Three major sources of error in GPS measurement

Satellite, receiver, atmospheric interference

Tool to create road buffers as a raster

Euclidean Distance

Do you need the internet to use GPS?

FALSE

Tobler's Law

Values close together are more likely to be similar

Components of a GPS signal

Navigation message, carrier waves, and digital codes

Map algebra

Analyzing stacks of raster maps using mathematical or Boolean operators

Better interpolation method has _____ RMS error

Lower

Raster function to identify slopes greater than 20 degrees

Raster Calculator

Function used to estimate values between known points

Interpolation

Tool used to map saltwater intrusion from chloride values

IDW

When automatic raster resampling occurs

When rasters with different cell sizes are used together

Why projected coordinate systems are important for rasters

Many raster tools rely on distance and area calculations

Reclassify function

Replaces ranges of raster values with new values

Semivariogram describes dissimilarity over distance

TRUE

Weighted overlay weights must sum to 1

TRUE

Lower DOP values indicate

Better satellite geometry and accuracy

Stochastic interpolation method

Kriging

Higher power in IDW means

Closer points have greater influence

Why rasters should share projection, extent, and cell size

To reduce resampling errors

Purpose of suitability criteria

Defines data, tools, and transformations used

Raster function that uses a moving window

Neighborhood Statistics

Purpose of an analysis mask

Exclude areas outside the area of interest

Cost-distance analysis determines

The easiest path between locations

How to normalize non-normal spatial data

Apply an empirical transformation

Deterministic vs geostatistical interpolation

Geostatistical uses spatial statistics

Purpose of cross-validation

Validate a model by systematically removing points

Einstein's relativity in GPS

Corrects for satellite time dilation

GPS code at 1.023 MHz

C/A Code

Factor that does NOT contribute to satellite error

Attitude Control

Other GNSS besides GPS

GLONASS, Galileo, BeiDou

Applications of suitability modeling

Locating parks, housing, agriculture, evacuation routes

Binary suitability modeling

Suitable (1) or not suitable (0)

Weighted overlay modeling

Uses ranked values with assigned weights

Fuzzy suitability modeling

Assigns values from 0 (unsuitable) to 1 (suitable)

Local raster operation

Analyzes a single cell

Neighborhood raster operation

Analyzes surrounding cells

Zonal raster operation

Analyzes cells within the same zone

Global raster operation

Analyzes the entire raster

Spatial autocorrelation

Nearby locations are more similar than distant ones

Limitation of deterministic interpolation

No estimate of uncertainty

Why DGPS improves accuracy

Reduces satellite clock, orbit, and atmospheric errors

Purpose of a semivariogram range

Distance where spatial autocorrelation ends

Why L-band is used for GPS

Penetrates clouds, rain, and vegetation