Termen GIS

GIS

A system used to collect, store, analyze, and display spatial data.

Spatial question

A question about location, patterns, trends, conditions, or implications.

Five components of GIS

Data, software, hardware, people/organisation, and rules/procedures.

Layered approach

GIS works with separate thematic layers that can be combined for analysis.

Spatial data

Data that refers to a location on Earth.

Attribute data

Non-spatial information that describes the characteristics of a feature.

Vector data

Coordinate-based data represented as points, lines, and polygons.

Raster data

Cell-based data arranged in a grid where each cell has a value.

Discrete data

Separate objects with clear boundaries, such as roads or buildings.

Continuous data

Data with a value everywhere in space, such as elevation or temperature.

Point

A vector feature representing a single location.

Line

A vector feature representing a linear object such as a road or river.

Polygon

A vector feature representing an area with boundaries.

Resolution

The size of raster cells; smaller cells mean more detail.

High resolution

Small raster cells, more detail, larger file size.

Low resolution

Large raster cells, less detail, smaller file size.

Large-scale map

A map showing a small area with much detail.

Small-scale map

A map showing a large area with less detail.

WGS84

A global geographic coordinate system using latitude and longitude.

RD New

The common projected coordinate system used in the Netherlands.

Projection

A method for representing the curved Earth on a flat map.

Why projection matters

Different projections affect area, distance, shape, and direction.

Topology

The spatial relationships between features in GIS.

Adjacency

A topological relationship where objects share a boundary.

Containment

A topological relationship where one object lies inside another.

Connectivity

A topological relationship showing that objects are linked.

Metadata

Data about data, such as source, date, scale, and coordinate system.

Primary data

Data collected directly from the real world.

Secondary data

Data created or collected by someone else.

Georeferencing

Assigning real-world coordinates to data such as a scanned map.

Digitizing

Converting analogue spatial data into digital GIS data.

Clip

A tool that cuts data to a specific boundary.

Buffer

A tool that creates a zone around a feature.

Erase

A tool that removes selected areas from a dataset.

Intersect

A tool that keeps only the overlapping parts of datasets.

Union

A tool that combines polygon layers into one output.

Near

A tool that calculates the distance to the nearest feature.

Reclassify

A tool that changes values into new categories.

Raster to Polygon

A tool that converts raster data into vector polygons.

Map Algebra

Raster calculations performed with raster layers.

Input

The starting dataset used in a GIS tool or model.

Tool

The GIS operation that processes the data.

Output

The result produced by a GIS tool or model.

GIS workflow

Spatial problem, data input, data maintenance, data analysis, data output, presentation.

Model

A simplified representation of reality or a process.

Conceptual model

A simplified diagram showing inputs, criteria, analysis, and outputs.

Geospatial model

A workflow that automates spatial data analysis.

ModelBuilder

A visual ArcGIS tool used to automate workflows.

Why ModelBuilder is useful

It improves automation, reproducibility, consistency, and transparency.

Basic ModelBuilder structure

Data → Tool → Output.

Reproducibility

The ability to repeat an analysis and get the same result.

Transparency

Making the analysis process clear and understandable.

Intermediate data

Temporary data created during model processing.

Parameter

A value required to run a tool, such as distance or output name.

MCA

Multi-Criteria Analysis; a method to combine multiple criteria to determine suitability.

Suitability map

A map showing which locations are more or less suitable based on criteria.

Equal weighting

Giving every criterion the same importance in MCA.

Weighted criteria

Giving some criteria more influence than others in MCA.

Socio-economic criteria

Human-related factors such as roads, buildings, or accessibility.

Ecological criteria

Nature-related factors such as habitats, wetlands, or protected areas.

Validation

Checking whether GIS results match reality.

Field validation

Comparing GIS data with real-world observations in the field.

Accuracy

How close data is to the true value.

Precision

The level of detail recorded in the data.

Error

A mistake or difference between GIS data and reality.

Bias

A systematic error that consistently shifts data in the same way.

Completeness

Whether all necessary data is included.

Consistency

Whether the same methods and rules are used throughout the dataset.

Compatibility

Whether datasets can be used together properly.

Applicability

Whether data is suitable for the intended purpose.

GIGO

Garbage in, garbage out; poor input data leads to poor output.

Generalization

Simplifying real-world detail in maps or GIS data.

Cartography

The science and art of making maps.

Purpose of a map

To communicate spatial information clearly and support decision making.

Title

A map element showing what the map is about.

Legend

A map element explaining symbols and colors.

Scale

A map element showing the relationship between map distance and real distance.

North arrow

A map element showing direction on the map.

Coordinate system

A system used to define location on Earth.

Source

A map element showing where the data comes from.

Visual hierarchy

A map design principle where the most important information stands out.

Sequential colors

Colors used for continuous data from low to high.

Categorical colors

Colors used for different classes or categories.

Map bias

Maps are not neutral because they select and simplify reality.

DEM

Digital Elevation Model; a raster dataset showing terrain height.

DTM

Digital Terrain Model; a model of the ground surface without buildings and trees.

DSM

Digital Surface Model; a model including buildings, trees, and other surface objects.

Flood modelling

Using GIS to predict areas that may be flooded.

Bathtub model

A simple flood model that identifies areas below a certain water level.

Connectivity in flooding

Flooding only occurs when low areas are connected to the water source.

Surface analysis

Analysis of 2.5D terrain data such as slope, aspect, or visibility.

Slope

The steepness of terrain.

Aspect

The direction a slope faces.

Hillshading

A visualization method that simulates light and shadow on terrain.

Viewshed

A map showing which areas are visible from a chosen location.

Network analysis

Analysis of connected lines such as roads, rivers, or electricity lines.

Shortest path problem

Finding the most efficient route between locations.

Location-allocation modelling

Determining the best location for services based on supply and demand.

Overlay

Combining multiple map layers to create a new dataset.

Point-in-polygon

Determining which polygon contains a point.