Originally Posted by grounded27
In my experience terrain DB's are global.
No, not so. The scope of the terrain database depends on what model of TAWS it will be loaded into. If your experience has been gained on Boeing or Airbus aircraft, it is understandable that you would presume databases are global. But, that is not so for all aircraft.
The TAWS that are intended for the commuter and regional aircraft market (for example, the Honeywell MK VI TAWS) can only hold 1/3 of the world. Honeywell has segmented the world up into three regions; Atlantic (Europe, Africa, Middle East), Americas (North and South America, including the western 1/5th of Greenland), and Pacific (Asia, Australia, and the Pacific Coast of North America). The operator chooses the appropriate database for the region that the regional/commuter aircraft will operate in - regional and commuter aircraft being, by definition, not used for intercontinental operations - then loads that database.
TAWS such as the MK V that are intended for use in large aircraft (Boeing or Airbus types) and in long-range corporate aircraft (Gulfstreams, Challengers, anything else that could reasonably be expected to operate intercontinentally) have a much larger flash memory storage capacity, and can hold a global database. The global database is nothing more than all three of the regional databases combined into one file.
The practice of having less flash memory in the regional aircraft TAWS dates from many years ago when flash memory was very expensive. Today, sufficient flash memory to hold the global database would probably only cost Honeywell about $5 per aircraft, however, there are two possible reasons why Honeywell has stuck with the original practice:
1) It's a difficult and painful process to get approval for hardware changes, and the existing model range of TAWS hardware is already approved, and;
2) Cynics might observe that Honeywell can charge a heck of a lot more money than just $5 for the airline and 'heavy iron' TAWS models that can contain a global database. Having hardware for two different segments (regional and intercontinental) allows Honeywell to charge intercontinental operators a premium price, but offer the same hardware at a significantly lower price to small aircraft operators who might be unwilling to pay the price charged to the big aircraft operators.
Anyone at all can go to the Honeywell website and see what the most recent release of TAWS data for the various models of TAWS is. The website (provided earlier in this discussion by another forum member) is Honeywell Aerospace - Database Services. It is necessary to register with Honeywell in order to be able to download the (free) database updates, however, it is not necessary to register - or have any login or password information - in order to find out what the version number of the most current database for your aircraft is. That information is at the bottom of that web page, along with the scheduled date for the next (upcoming) update. You will, however, need to know what kind of TAWS (EGPWS, to use Honeywell's trademark for their version of TAWS) you have installed in your aircraft in order to make sense of the release schedule.
Pilots who fly aircraft equipped with Honeywell TAWS equipment can easily determine what database version is installed in their aircraft by invoking the "TAWS Test" function. A multicoloured test screen will appear, and in the middle of the test screen, you will see a number. That number is the version number of the currently loaded database. At the same time, the TAWS will voice several aural alerts (PULL UP, TERRAIN, or similar).
The picture below shows the test screen from a Twin Otter aircraft that has Terrain Data Base (TDB) version 450 installed. The N after the version number means it is an Americas database. An A after the version number would mean an Atlantic database, and a P after the version number would mean a Pacific database.
Hope this information helps.
It's also worth mentioning that if pilots are really curious about what data is contained in their Honeywell EGPWS database, it is possible to go to a different Honeywell website and download an Excel spreadsheet that lists every single runway at every single airport that is contained in the world database.
This document does not tell you what areas of the world (away from runways) have been mapped for terrain height, or with what precision (in arc-seconds) various areas of the world have been mapped for terrain height, but it does tell you which runways ('runways' implies final approaches) have been mapped. When a runway is included in the terrain database, the TAWS will know that it is 'acceptable' for the aircraft to descend closer and closer to the ground (eventually reaching the ground and landing on it), provided that the aircraft stays laterally within the appropriate confines of the extended centerline, and provided that the vertical descent path angle of the aircraft is 'sensible' for the runway to which the approach is being conducted.
Other factors are also considered during the final approach - radar altitude, glideslope deviation, aircraft configuration, rate of descent, and so forth - to determine whether the TAWS stays silent or whether it generates an alert, but, if a particular runway has been mapped for the database, this means that the likelihood of hearing a spurious terrain alert during approach is very, very low; provided that the aircraft follows a published approach.
Here is the website you can go to to download all the details about the current database release: Honeywell EGPWS Airport / Runway Search. You can also enter the Airport Name, City Name, Country Name, or ICAO Airport Identification Code and look up specific information that way, without having to download the entire Excel document.
The soil and physiographic database for north and central eurasia covers China, Mongolia and all countries of the former Soviet Union. The soil information has been derived from several sources, in particular the 1:2.5M Soil Map of the Former Soviet Union prepared by Friedland in the Dokuchaiev Institute, Moscow; and the soil map of China at 1:4M prepared by the Soil Science Institute of the Academia Sinica in Nan-Jing. All soil information has been correlated with the Revised Legend of the Soil Map of the World.Soil and Terrain database for China
The Soil and Terrain database for China primary data (version 1.0), at scale 1:1 million (SOTER_China), was compiled of enhanced soil information within the framework of the FAO's program of Land Degradation Assessment in Drylands (LADA). The primary database was compiled using the SOTER methodology. The SOTER unit delineation was based on a raster format of the soil map of China, correlated and converted to FAO’s Revised Legend (1988), in combination with a SOTER landform characterization derived from Shuttle Radar Topographic Mission (SRTM) 90 m digital elevation model (DEM). Reference profiles for the dominant soil of the SOTER units has been directly linked to the polygons.
SOTER forms a part of the ongoing activities of ISRIC. FAO and UNEP to update the world's baseline information on natural resources. The project involved collaboration with national soil institutes from the countries in the region as well as individual experts.Country Soil Maps and Geographic Databases
The ASRIS map window provides access to a Geographic Information System via the web. The maps are created in response to the settings you specify with the buttons and selectors. Map layers are the different sets of information that can be added to your map. The system can add and subtract layers from the map according to the scale. This stops your map becoming cluttered with lots of fine detail when large areas are being viewed.New-Zealand
S-map provide a seamless digital soil map coverage for New Zealand. S-map is designed to be applied at any scale from farm to region to nation.
Existing soil databases are patchy in scale, age and quality. Many maps do not adequately describe the underlying properties of the soil types they represent. S-map integrates existing reports and digital information and updates soil maps where existing data are of low quality. The goal is to provide comprehensive, quantitative soil information to support sustainable development and scientific modelling.Papua New Guinea
PNG National Agricultural Research Institute - Mapping and geographical information systems
This unit of NARI provides technical advice on Geographical Information Systems and produces maps that when retrieved and manipulated can enable one to have a “birds eye view” of natural resources and agricultural practices or crops grown in different parts of the country. There are three major agricultural databases kept at NARI. These databases are available in a Geographical Information Systems format or simply map-linked databases. They can be presented as maps, tables and graphs.These databases are relevant to Researchers, Agriculturalists, Planners, Investors, Environmentalists, Schools and Universities or to anyone involved in planning development and land management in PNG.
Last Update: December 12, 2016
Goal: To increase pilot situational awareness both on the ground and airborne to improve safety and efficiency of flight.
Airport Mapping Database: ARINC Specification 816 defines encoding formats for airport mapping databases that can be loaded directly into airborne systems, thus enhancing taxi operations. When designed and implemented, this ARINC Standard will enable a quick, economic, and efficient use of airport databases in every aircraft.
Terrain Database: ARINC Project Paper 813 will define encoding formats for terrain databases that can be loaded directly into airborne systems, thus enhancing flight crew situational awareness. This will enhance the value of Terrain Avoidance and Warning Systems (TAWS), Vertical Situation Displays (VSD), Synthetic Vision Systems (SVS), and enroute mapping.
Obstacle Database: ARINC Project Paper 815 will define encoding formats for obstacle databases that can be loaded directly into airborne systems, thus enhancing flight crew situational awareness. This will enhance the value of Terrain Avoidance and Warning Systems (TAWS), Vertical Situation Displays (VSD), Synthetic Vision Systems (SVS), and enroute mapping.
XML Encoding and Compression: ARINC Specification 814 defines a single XML encoding and compression standard that can be invoked by any ARINC Standard to optimize database storage and processing efficiency on the aircraft side. This ARINC Standard was developed in conjunction with Airport, Terrain, and Obstacle Databases.
Standardized airport, terrain, and obstacle databases will enable database providers and airborne system suppliers to use a common encoding format. This fosters competition among the database providers. The airlines can select a supplier of data without impact on the airborne system. Use of standardized airport, terrain and obstacle databases will lead to operational improvements in taxi operations as well as in flight. These improvements translate into economic benefit to the airlines.
Next Meeting Announcement:Staff Contact
The Jeppesen Terrain Database provides the latest generation of terrain data for prevention of controlled flight into terrain and terrain avoidance warning systems (TAWS) to be used by pilots, dispatch, and other flight operations planners.
The Jeppesen Obstacle Database is the world's most complete database of obstacles relevant to aviation. The database contains man-made and certain natural obstacles extracted from digital and paper sources provided by governmental civil aviation authorities and military agencies worldwide.
Please contact one of our sales representatives by using the phone numbers on the left or fill out a request for product information form for further information about our products and services.
By Colin Childs, Esri Writer
This article as a PDF .
Terrain datasets in a geodatabase can help effectively manage, process, and integrate massive point collections of the 3D data that result from collecting high-resolution elevation observations using lidar, sonar, and other technologies.
Terrain datasets, which live inside geodatabases, offer many advantages for managing surface data.
Terrain data is usually expressed as a series or collection of points with x-, y-, and associated z-values. It generally includes a series of points representing the high and low extremes in the terrain that define topographic features such as streams, levees, ridges, and other phenomena.
With ArcGIS 9.2, Esri introduced the terrain dataset to better handle surface data. This multiresolution, triangulated irregular network (TIN)-based surface is generated using measurements stored as features in geodatabase feature classes. TINs are assembled from a series of data points with x-, y-, and z-values and partition geographic space into contiguous, nonoverlapping triangles (called faces). The nodes of each triangle have an x,y coordinate and a z-value representing the elevation or surface value at that location. Using the TIN, any surface value can be interpolated within a face or along an edge.
Source point and breakline data
Additional rules are defined to generate TIN pyramids representing elevation change.
While there are many reasons for using terrain datasets to manage surface data, here are 10 of the most compelling ones:
Terrain datasets scale to handle vector-based source measurement data such as lidar, photogrammetric, and sonar data. Traditionally, ArcGIS uses feature data, like 3D points, lines, and contours, to make TINs and grids. These surface storage and representation methods are not well suited to large collections of mass point data from sources such as lidar, photogrammetric, and multibeam sonar data.
An ArcGIS terrain dataset offers a database-oriented solution for managing these vector-based source measurements. This is achieved through the use of an updated and efficient TIN-based data structure that generates a multiresolution surface that is created on the fly for a given area of interest and level of detail. The terrain dataset supports point, multipoint, polyline, and polygon-based features and is seamless, fast, and scalable.
Because source measurements are stored, not a derivative surface, they can be edited and replaced with more current or accurate data at anytime.2. Effective data management
Terrain datasets and the data used to define them are stored and maintained in a feature dataset in a geodatabase. Consequently, the data management advantages of the geodatabase are available to terrain datasets.
While terrain datasets are supported in all ArcGIS geodatabase formats, it is important to note that these formats have inherent differences in capacities. An ArcSDE geodatabase is the most capable format and is appropriate for terrains involving billions of points and workflows that use a centralized database to manage source measures and terrain datasets in a multiuser editing and versioning environment. File geodatabases can be used for terrains with billions of points but do not allow multiuser editing. Personal geodatabases are the least desirable for terrain datasets, and their use should be restricted to terrains with fewer than 20 million points.
In ArcSDE, versioned terrain datasets support multiple users accessing different representations of the terrain for different projects. What-if scenarios can be modeled by allowing design edits that model proposed changes to be made without actually changing the original surface. If the design is realized, the edits can be posted back to the source data. Possible editing scenarios include workflows in which operators are restricted to editing data layers within constrained areas or workflows in which operators are responsible for edits to individual layers for unconstrained areas such as all lidar data.
The terrain dataset references participating feature classes (source measures) that define how they contribute to the terrain and maintain the rules specifying how these source measures are used within the terrain dataset. Because source measurements are stored, not a derivative surface, they can be edited and replaced with more current or accurate data at any time. Terrains enable users to own and manage the source data and derive end-user products as needed.
In the case of lidar data, some phenomena may be oversampled. Point thinning filters retain only those measurements needed to represent the phenomena.
Edit a terrain by editing the feature classes that participate in it using standard editing tools. Simply add, remove, or replace data referenced by the terrain. Measurement data can be managed over time, and the terrain dataset can grow as additional or more current data becomes available.3. Simple workflow for creating terrain dataset
Use the Terrain wizard to create a new terrain dataset in a feature dataset in a geodatabase. In the wizard, supply a name for the new terrain dataset and specify the participating feature classes. In addition, point spacing information, which is collected for photogrammetric, lidar, and sonar surveys and supplied with the source data, can also be specified.
A terrain layer is similar to a TIN layer in that it supports multiple renderers. Triangles in a terrain layer can be symbolized by elevation range, slope, aspect, and hillshade.
The ArcGIS 3D Analyst toolbar provides interactive tools for many types of analysis including the creation of profile graphs.4. Vector-based pyramids for rapid display
Rendering very large TINs is generally difficult, partially due to limitations of hardware, such as video cards, and therefore, terrains are beneficial in that areas to be visualized are rendered at an optimized resolution. Terrain datasets employ pyramiding— a form of scale-dependent generalization—when displaying a surface.
The vector-based pyramid levels in terrain datasets are similar to raster pyramids and take advantage of the diminishing accuracy requirements as scales decrease. For each successive pyramid level, as the accuracy requirements necessary to display the surface drop, fewer measurements are used, although the original source measurements are used in these coarser resolution pyramids. No resampling, averaging, or derivative data is used for pyramids.
Since a terrain dataset deploys pyramid levels, ArcMap is able to rapidly generate a TIN surface on the fly at whatever resolution is needed for the scale of the viewer. In the case of lidar data, some phenomena tend to be oversampled so using point thinning filters to retain only those measurements needed to represent the phenomena is important.
When displaying terrain datasets, a terrain layer is created. This layer type is similar to a TIN layer in some regards, as it supports multiple renderers. With a terrain layer, it is possible to color triangles by elevation range, slope, aspect, and hillshade. It is also possible to see the breaklines, triangle edges, and nodes of the triangulated surface.
Terrain datasets are supported for reading and viewing at all licensing levels. However, a terrain can only be created with the ArcGIS 3D Analyst extension. In addition, terrain datasets are not directly supported in ArcScene. The recommended workflow for displaying terrains in ArcGlobe is to make a raster from the source terrain dataset and use this in ArcGlobe.5. Improved efficiency with point clustering
Multipoints are often used to manage arrays of large point collections, such as lidar point clusters, which can contain literally billions of points. Using a single row for such point geometry is not feasible. Clustering these into multipoint rows enables the geodatabase to handle massive point sets. Clustered multipoints are highly compressed in file geodatabases and SDE, which reduces storage and I/O requirements.6. Optionally embed point data
Despite clustering and compression, lidar can still require a significant amount of storage space. An option for large multipoint feature classes is to embed them within the terrain dataset as a way to save storage space. Embedding is performed during the terrain build process. Point geometry and (optionally) lidar attributes are copied directly into the terrain pyramid structure. After the terrain is built, it becomes the container of the points and no longer references the source feature class. This means that the source feature class can be deleted, reducing the storage space required.7. Support of industry-standard LAS format
The LAS file format is an open standard file format for the interchange of lidar data. It is a binary file format that maintains specific information related to lidar data and is a way for vendors and clients to interchange data and maintain all information specific to that data. Using a LAS file format avoids some of the pitfalls associated with ASCII format points, as the extent, point count, and spatial reference are contained in the header.
ArcGIS uses an updated and efficient TIN-based data structure that generates a multiresolution surface that is created on the fly for a given area of interest and level of detail.
An efficient and cost-effective solution for utilizing LAS point attributes is to use them with a query filter during conversion of LAS points to Multipoint. By doing this, LAS attributes, such as class code or return number, can be used to extract just the points needed, and there is no need to import the attributes.8. Extensive collection of terrain geoprocessing tools
The geoprocessing tools that interact with terrain datasets are kept primarily within the 3D Analyst toolset and are intended to facilitate automation through the use of scripts and models. These 26 tools are located in these toolsets:
Surface analysis is sometimes best executed interactively rather than in batch mode using geoprocessing tools. The ArcGIS 3D Analyst toolbar provides interactive tools that create contours, create the steepest path, create a line of sight, interpolate point/line/polygon, and create profile graphs.
Surface analysis involves several kinds of processing, including extracting new surfaces from existing surfaces, reclassifying surfaces, and combining surfaces. Some of the types of surface analysis that can be executed using a terrain dataset include
The ASCII format for lidar is not generally recommended, but many legacy data formats often use ASCII as an interchange medium, and thus this workflow is available. ASCII source data in XYZ, XYZI, or 3D ASCII Generate formats can be imported into feature classes using the ASCII 3D To Feature Class geoprocessing tool. After conversion to a feature class, this data can be incorporated into a terrain dataset.Conclusion
The terrain dataset contributes to effective workflows with lidar and other mass point collection data types by providing scalable, efficient data storage and rapid visualization and enabling powerful surface analysis.