Service New Brunswick Spatial Data

• What do I actually download?
• What is the relationship between ETB, DTM, DTDB and the file that I actually downloaded?

What do I actually download?

When you download a DTDB map, you are actually downloading a compressed file (i.e. a .zip file) which consists of several files. The number and names of the files, contained in the .zip file, will differ depending on the version of the DTDB that you selected from. Recall that there are two versions of the DTDB (DTDB96 and DTDB98).

DTDB98

Each map that gets downloaded to desktop (i.e. each .zip file) consists of 11 files. These 11 files are described in the following table:

Table: DTDB98 Files

• 4 of the above files are in CARIS ASCII format. These files are suitable for input into CARIS. These 4 files constitute the ETB map in CARIS format.
• 4 of the above files are in DXF format. These files are suitable for input into a GIS (such as ArcView) and CAD systems.
• 3 of the above files are simple text files. These are suitable for input into a DBMS (such as MSAccess)

For a detailed description of the above files please see"User Guide to the Digital Topographic Data Base 1998 (DTDB98) of New Brunswick".

Example:
If you selected Map Number 46006690 for download to your desktop, you would download the file 46006690.zip. The contents of the file would be as follows

What is the relationship between ETB, DTM, DTDB and the file that I actually downloaded?

The Digital topographic database (DTDB) is a digital representation of natural and cultural features, organized into files. It is made up of two databases: Digital Terrain Model database (DTM) and the Enhanced Topographic Database (ETB). The Digital topographic database consists of 1894 files. Each DTDB file contains two types of data:

• DTM data ... elevation data
• ETB data ... topographic data (roads, rivers, lakes, land cover, etc.) stored in a 2D coordinate system

This means that each file that you download to your desktop contains DTM data and enhanced topographic data.

Recall from above that each DTDB file consists of 11 files. The DTM data is stored in two files (extensions .d98 and .xyz). Each file contains identical information but is in a different format. One of the files is suitable for input into CARIS (.d98). The other file is suitable for input into ArcView (.xyz).

The enhanced topographic data is stored in 11 files. 3 of these files contain attribute (or non-spatial information). 8 of these files contain graphic information. Of these 8 files, 4 are suitable for input into CARIS and 4 are suitable for input into ArcView.