Overlays 1
This type of GIS overlay combines data from two layers to identify where both datasets share common features or attributes.
What is an intersect?
In an attribute-based GIS overlay, this operation is often used to merge two datasets based on a common attribute field, creating a new attribute table.
What is a spatial join?
This popular GIS software provides tools for performing both vector and raster overlay operations, allowing users to combine and analyze multiple layers.
What is ArcGIS?
This map projection preserves shape but distorts size, making it useful for navigational charts.
What is a Conformal projection (e.g., Mercator)?
This coordinate system uses angular measurements (latitude and longitude) to specify locations on the Earth's surface.
What is a Geographic Coordinate System (GCS)?
In this overlay method, a new layer is created by taking the features of two layers, combining all features from both and preserving their geometry.
What is a union?
This type of GIS data is most commonly used for overlay operations where features are represented by points, lines, and polygons.
What is vector data?
This GIS overlay analysis is commonly used to assess how environmental factors, like land use or elevation, overlap with endangered species habitats.
What is a suitability analysis?
This type of map projection minimizes distortion in area, making it ideal for representing large areas such as continents or countries.
What is an Equal-area projection (e.g., Albers Equal Area or Gall-Peters)?
This type of coordinate system, often used for local or regional mapping, uses perpendicular X and Y axes to represent positions on a flat surface.
What is a Projected Coordinate System (PCS)?
This GIS overlay operation involves selecting the area from one layer that is entirely within the boundaries of another layer.
What is a clip?
In map-making, when you perform an overlay of multiple layers, this type of map helps show the relationships and patterns between them, often used for thematic mapping.
What is a composite map?
This type of overlay operation allows you to combine multiple layers, preserving all the original data, including any non-overlapping areas.
What is a union?
This family of map projections, which includes the Lambert Conformal Conic, is known for its ability to preserve angles, making it useful for aeronautical charts.
What is a Conic projection?
This geodetic datum, used by GPS, is the most common reference system for the global geographic coordinate system, defining the Earth's shape and size.
What is the WGS84 (World Geodetic System 1984)?
In this overlay operation, the results show all areas where one or more features overlap between two or more layers.
What is an intersection?
This overlay method allows you to analyze the interaction between two datasets by considering their spatial relationships, such as adjacency or containment.
What is a topological overlay?
In this GIS overlay operation, a raster layer is used to mask out areas in a vector layer, so only data within the raster's defined areas is retained in the output.
What is a rasterize overlay?
This widely used map projection distorts both size and shape but shows the entire globe in a rectangular form, often used in web mapping services.
What is a Web Mercator projection?
In this coordinate system, coordinates are defined relative to a central meridian and a standard parallel, commonly used in large-scale mapping for specific regions.
What is the State Plane Coordinate System (SPCS)?
When performing an overlay on raster data, this operation calculates the cell-wise maximum or minimum between two raster layers.
What is a local operation?
This GIS overlay tool uses the geometry of one layer to subtract features from another layer, creating a new layer that only includes the features of the original minus the overlaid features.
What is a difference?
This technique is used when you want to determine which features from one layer are completely within the bounds of features in another layer.
What is a containment overlay?
This map projection type attempts to maintain equal distances from a central point, making it useful for mapping areas close to the equator or poles.
What is an Equidistant projection?
When converting between coordinate systems, this term describes the transformation needed to account for the differences between geographic and projected coordinate systems.
What is a datum transformation?