Making use of GIS software
- geographical "culture" such as
and vegetation is traditionally managed
in 2D by the
- a lot of the VTP software development, especially on vegetation coverage
and raw feature layers, is starting to resemble GIS functionality
- from the other direction, GIS tools are attempting to move toward 3D,
but are still fairly early in that process
- how can the terrain visualization field leverage or take advantage of
existing GIS tools?
GIS Software, Open
- QGIS and
gvSIG are among the most
prominent of the open-source GIS tools
- They both run on desktop and mobile, both read a myriad of formats
and have decent user bases.
- As of 2012, gvSIG has the more extensive 3D support.
- "raster, topological vector, image processing, and
graphics production functionality"
Includes some 2.5D and 3D visualization capabilities.
- Unfortunately, it bears a lot of historical baggage; from 2002 to
2010, despite repeatedly attempts and much effort, i did not manage to get it to open any dataset.
- For those who do manage to get GRASS working, there is an
interesting module NVIZ with
some virtual terrain capabilities: "NVIZ allows users to realistically render multiple surfaces in
a 3D space, optionally using thematic coloring, draping GRASS vector
files over the surfaces, and displaying GRASS site files either
draped on the surfaces or as 3D point locations."
- An open-source GIS application with an emphasis on scientific grid and raster
functions: digital terrain analysis, geo-statistics, image processing.
- Imports all of the
GDAL formats, exports ArcGrid and Surfer. Has an API so that people can easily add modules to it.
GIS Software, Closed
ArcGIS (around $1000 for the entry level)
- The most widely used GIS package, usually sold through dealers / resellers.
- For 3D, there is add-in called
Analyst (see Commercial Tools)
- was the leading competitor to ESRI, but now FOSS packages like QGIS
are a more relevant alternative
- some 3D possibilities exist with the optional
Vertical Mapper (~$1200?)
which from the marketing literature doesn't sound as impressive as 3D
- a lower-cost alternative to the "big two", has all the usual 2D GIS
- as of version 4.5, it added some 3D support including the ability to
turn contours into a heightfield and do a flyover
- "Drape a map over a surface to see the map in three dimensions and
control the display of 3-D maps with the new 3D Toolbox."
- 3d operations: calculate spot heights, viewsheds, shortest path over
- Manifold ($300 and up,
- A very low-cost GIS package that claims to have all the same
features as the other more expensive tools, e.g. ArcGIS and MapInfo
- consists of a large
products, "3D visualization is a built-in part of every Manifold
Cadcorp SIS ($?)
- a freeware GIS (Windows only) once with an emphasis on forestry, but
as of 2005 a general-purpose GIS
- supports a huge number of raster and vectors formats; seems to do a wide
variety of common GIS tasks
GIS Data Formats
- ESRI Shapefiles (SHP)
- these are output from the commercial GIS tools ArcInfo and ArcGIS
- it is a very common format for geographical coverages such as
land use, vegetation, etc.
- it contains "vector data" which can be point, lines or polygons
- documented in an ESRI whitepaper:
Shapefile Technical Description
- consists of up to 4 files:
- .SHP - main file, contains geometry only
- .SHX - index file, always accompanies the .SHP
- .DBF - database file that contain attributes for each
entity in the SHP file
- .PRJ - contains projection information (only rarely
- there are many available
libraries which read and write SHP/SHX/DBF nicely
- ESRI ArcInfo Export files
- a proprietary, inefficient ASCII format which is exported by ESRI's
high-end ArcInfo program
- there is no official documentation, but some
- it can contain either vector or raster data
- MapInfo files
- file extension for their "interchange" format is .MID/.MIF
- standard binary form ("TAB") has extensions .TAB,
.MAP, .ID, .IND
- can be read by the MITAB
library, which is part of the OGR
- There have been many proposed "replacements" for the ubiquitous
Shapefile format, but no clear leader.
GIS Data Model Standards
- traditionally, there has been no standards for GIS attributes making
data interchange of real-world data prohibitively complicated in general
- ESRI has begun the process of defining 'ArcGIS
Desktop Data Models'
- the good news is that there are 19 areas, and it looks to be growing
- the bad news is that the standardization is
strongly oriented toward
abstract values rather than physical descriptions, although there are
very low-level physical details e.g. the Pipeline Datamodel defines
attributes for 'OutsideDiameter' and 'WallThickness'
- probably the most relevant area to the VTP
Basemap Data Models such as for Transportation and Hydro, although
these appears to be just draft examples so far
Generalizing GIS: Development of Spatial Grammars for Landscape Planning
(pdf), Kevin Mayall and G. Brent Hall
- proposes the odd idea of using shape
grammars (more commonly used to describe buildings or cities) as a way
of generating or analyzing general GIS data