Features

Remcom Inc.315 S. Allen St., Suite 416 State College, PA 16801 USA

Tel: 1-814-861-1299 Fax: 1-814-861-1308 sales@remcom.com www.remcom.com© 2011 Remcom Inc. All rights reserved.

What are Features?

• Types: City, Terrain, Foliage, Indoor Floor Plan and Object

• Hierarchical organization: Feature Structure group Structure Sub-structure Face

• Geometrical data in vector format• Electromagnetic material properties• Display properties• Geographic positioning and reference system

Hierarchical Organization of FeaturesH ie ra rch ica l la yo u t o f a s tru c tu re

F a ce F a ce F a ce F a ce

S u b -s tru c tu re

S truc tu re S truc tu re

S truc tu re g ro up

F e atu re(C ity, T e rra in , e tc)

Feature

Structure Group

Structure

Sub-Structure

Face

Motivation for Hierarchy

• Having a multi-layered topology provides the user with flexibility

• Tools will be added to allow more extensive editing of the organization of these layers

Geometry File Formats

• All feature types use a very similar file format described in the Appendix in the User’s Manual

• Usually, files only differ by extension and the highest level “delimiter”

• File extensions: – .city for buildings– .ter for terrain– .veg for foliage– .flp for indoor floor plans– .obj for objects

Importing Building Data

• InSite’s physics-based propagation models require full three-dimensional building data

• Accurate data for a large number of cities is now available from a growing number of sources

• Data is often available in AutoCAD’s DXF format• After importing, material properties can be quickly

assigned to each building with the GUI• Buildings are automatically fit to the underlying terrain• Imported building data can be in latitude/longitude, UTM,

or Cartesian coordinates

Fitting Buildings to Terrain

• Enabled when terrain is present in the project• Options are to extrude the footprint of all sub-

structures down to the terrain, or to lower the entire sub-structure to the terrain. With extrusion, the roofs of the sub-structures remain constant.

• Building is either extruded or lowered to the minimum terrain elevation below each sub-structure

Importing DXF Files

• Primarily used for importing city data• Coordinate system used in the DXF file must be

known• Whether the elevations in the file are relative to

sea level or terrain must be known• Wall materials and roof material can be set

independently

Allowed DXF Data Types

• InSite is only capable of converting the following DXF tags:– Polylines– Polyface meshes– 3D faces

• Roofs should be placed on top of all buildings to ensure calculations are performed correctly

• “Floor” faces on the bottom of the building are not usually necessary, but can be retained if they are present in the DXF file

Importing ESRI Shapefiles

• To import an ESRI shapefile containing building footprint and height information into the current project, select ProjectImportShapefile

• Only polygon and polygonZ shape entities are supported

• Some shapefiles are accompanied by a .prj file containing coordinate projection information. The .prj file projection information is not currently supported and the imported geometry may not be correctly geo-referenced.

Raster Data Import

• Raster data files contain grids of height values

• Data usually measured from aerial or satellite photography or LIDAR

• Raster converter extracts footprints from the grids and creates buildings from the footprints

Raster Data Import (2)

• Raster Data Import window previews raster and vector data• Allows cropping, scaling and extrusion• Supports PGM and ARC ASCII grid files

Building Preprocessor

• InSite’s building preprocessor puts data into a form ready for calculation

• Building databases are usually obtained from high resolution aerial photographs and will often include very small features which can lead to long computation times and, in some cases, less accurate results

• Remcom’s building simplification algorithms are based on removing small building faces, combining nearby coplanar faces, and removing concave corners

• The change in the area and perimeter of the footprint is monitored during modification to avoid changes which distort the basic shape of the building

Building Simplification Interface

Building Preprocessor Example:Before

Before

Building Preprocessor Example:After

After

City Editor

• Draw footprints of new buildings (sub-structures) and then set height

• Edit and delete existing buildings

• “Snap-to” grid lines and vertex options are available

• Active images will appear in the editor window

Origin of Cartesian Reference Frame

• Wireless InSite supports data in:– Cartesian form relative to an origin at a given latitude/longitude– Latitude/Longitude– UTM using various ellipsoids

• Points close to the origin are transformed with least error• All feature origins do not have to use the same latitude

and longitude • It is recommended that foliage items and terrains have

the same origin• A feature’s default origin is determined from the first

point read in and is centered on imported terrains

The Global Origin

• Wireless InSite converts all projections to Cartesian for display and for calculation

• A global origin is determined from all loaded features, transmitters, receivers and study areas– Usually the minimum of all geometrical elements– Can be manually set in order to reduce error

Geographic Projections

• Everything positioned in a project has an origin• Every origin has a latitude/longitude• Cartesian data includes latitude/longitude of

origin

Transform to Cartesian Coordinates

• Coordinates given in UTM are first converted to latitude/longitude

• Coordinates in latitude/longitude are converted to Cartesian coordinates using:X = REarth * cos(0) * ( - 0)

Y = REarth * ( - 0 )

Where = Latitude

= Longitude

0 = Global origin latitude

0 = Global origin longitude in radians, and REarth is the mean radius of the earth

Minimizing Projection Error

• By default, the global origin is set to minimum latitude/longitude– Unfortunately, this can introduce errors in relative

positions

• Averaging all latitude/longitude values to determine the global origin produces less error

• Averaging the locations of all vertices will produce the least amount of error

Materials

• Each feature maintains its own list of material definitions for all items within it

• Predefined types are accessible in the Material database• Identified by an integer value within each feature file• Each face is assigned a material using this integer• A face can be double-sided (mainly indoor)

– Material thickness is used to display depth in walls– Same material will be assigned to both sides

• Material properties, with respect to the calculation, are covered in another section

Material Type Legend

• A color coded legend of all materials in a project can display on the right side of the project view

• Clicking on an entry in this table brings up the material’s properties, which can be edited

Terrain• A new terrain can be created either as a rectangular

region or as a profile• The editor that is available is determined by which

type of terrain is being created/edited

Editing a terrain surfaceEditing a terrain profile

Terrain Surface Editor

• Points can be moved and added• Point elevation is changed by right clicking• Terrain can be created as a grid initially• Heights can automatically be set to either fit the

terrain or to lower the edges of buildings• Useful for creating relatively simple terrains to

place below cities

Terrain Profile Editor

• Points can be added or removed from the profile• Points can be moved within the profile as long

as it remains between the points to its side• To modify the material on a face to the right of a

point, right-click on the point and select the Modify option from the context menu

Importing Terrain

• Terrain can be imported from USGS, DTED, or DTA (SoftWright) data files– DTED levels 0, 1, 2– USGS 7.5’, and 1º

DEMs – 30” DTA

Importing Terrain (2)

• A region of any size can be imported. It is recommended that users adjust the settings of the importer to minimize the number of faces while retaining the accuracy of the calculation.

• Local repositories of terrain data can be indexed to allow Wireless InSite to locate the files it needs automatically

• A terrain can be imported as a profile or a rectangular region

View of Terrain in Colorado Mountains with Tx and Rx Locations

Foliage Data

• Foliage can be imported from the Global Land Cover Characteristics (GLCC) database available from the Land Processes Distributed Active Archive Center (LDAAC) website

• New foliage can be created manually using the Foliage editor

Foliage Editor

• Works in a manner very similar to the City editor • New foliage areas can be added/deleted• Points can be moved or deleted after a foliage

area has been created• The height of individual foliage areas can be

adjusted• Foliage areas can be conformed to the terrain

Foliage Editor (2)

Foliage Database

• Geo-referenced foliage information can be imported using the Global Land Cover Characteristics (GLCC) version 2 database

• Data is available through the Land Processes Distributed Active Archive Center (LDAAC) website

• Includes foliage information in 1km2 resolution and is available for 5 major geographical regions; Africa, Australia Pacific, Eurasia, North America and South America

• During the import process foliage areas can be previewed. This enables the user to cut out unnecessary/unwanted foliage areas and make adjustments to the materials

Foliage Capabilities

• Foliage areas can be created and edited from the GUI• The horizontal footprint is defined first using the GUI’s

drawing tools• An upper and lower height can be assigned to each area• Areas can be stacked vertically in order to distinguish

between the canopy and the undergrowth• An effective permittivity and conductivity is assigned to

each area• A roughness parameter can be assigned to each face

Foliage Capabilities (2)

• Transmitters and receivers can be inside or outside of foliage areas

• No change in direction of rays through foliage is calculated

• The distance propagated through each foliage area is found for each ray path

• An exponential decay is applied to each E-field• Phase change of E-field can be also included• Lateral wave along canopy-air interface is also included

Foliage Capabilities (3)• Foliage areas can be created and

edited from the GUI

• The horizontal footprint is defined first using the GUI’s drawing tools

• An upper and lower height can be assigned to each area

• Areas can be stacked vertically in order to distinguish between the canopy and the undergrowth

• An effective permittivity and conductivity is assigned to each area

Foliage Areas in an Urban Environment