GWR 3D Mapping
ESRI online course on
Data in Three Dimensions: A
Guide to ArcGIS 3D Analyst
(Thomson/Delmar Learning, 2004).
I: Background for 3D & ArcScene
Surfaces & features: a map layer may contain surfaces or features.
Surfaces: model a phenomenon that varies continuously across an
area (e.g., elevation, slope, aspect, rainfall).
Surfaces are modeled
data (i.e. consisting of grids of identically sized cells, or
pixels, each of which represents a unit of surface areas & stores a
measured or estimated value for a particular unit).
A surface can be estimated from sampled data via
(see Spatial Analyst and Geostatistical Analyst: e.g., IDW,
spline, nearest neighbor, kriging; see ArcGIS help).
Features: entities with discrete boundaries (e.g., houses, districts);
features are represented
data (i.e. by a polygon, line, or point).
Features are represented by 2D or 3D
of like features)
such as shapefiles and geodatabases.
3D feature: a point, line, or polygon with not only x,y
coordinates also z-values as parts of its geometry.
A z-value stores a measurement such as a base height.
A point stores has one z-value, while lines & polygons
have a single z-value for each vertex in the shape.
How to identify shapefiles & geodatabase feature classes
that store 3D features: the ‘shape’ field in the attribute
table contains z-values that end with ‘ZM’ (e.g.,
(i.e. Triangulated Irregular Network) represents
space via a set of non-overlapping triangles that border
each other & vary in size & proportion.
A TIN is created from a set of input points with x,
y, & z values; the points become triangle vertices
(nodes) that are connected by lines that form
boundaries (edges)—a final product that is a
continuous surface of triangles made of nodes &
Slope & aspect can be calculated for each triangle
3D features are manipulated in ArcMap via
which you need to load (
menu>3D view tools).
II: 3D in ArcCatalog
Note: see Part VI, “Trouble shooting”
How to preview 3D features in ArcCatalog:
Note the symbols that represent a TIN & a raster.