Back
| Flora Danica Online Homepage | Search
Flora Danica | DNLB Homepage
 |
Flora Danica Online
Information about the project
|
Contents
Digitization
Contents
The digitizing of Flora Danica is part of a CultureNet
Denmark project carried out at The Danish National Library of Science and
Medicine (DNLB). The purpose of the project is to publish Danish plates of
natural history on the WWW.
The project began in the spring of 1997 and the Flora Danica part is planned
to be finished at the end of the year. When finished all 3240 plates will be
available on the WWW. It will be posssible to search individual plants and to
browse the plates.
The structure of the Image Database
The project is sponsored by the Danish Ministry of Cultural Affairs.
The names of the plants
Nomina emendata
Contents
For the time being there are two different names for the plants in the
database, both in Latin. The reason for this is that the naming of plants has
changed over the years.
The two names are:
- The name given in Flora Danica.
- The "emended" name (Nomina emendata) given by John Lange in his
key to Flora Danica from 1877. These "nomina emendata" were the
correct scientific terms at the time, but they are not in accordance with
present-day usage. They are, however, still used by botanists as a key to
Flora Danica.
Work is being done to make it possible to enlarge the database with the
current Latin names and names in Danish. As to the latter it should perhaps be
mentioned that far from all the plants in Flora Danica have Danish names - and
sometimes they designate two or more different plants.
It is at present not at all certain that the work will be met with success.
Hardware and software used
Contents
The following hardware and software is used for the project:
- A 4×5" camera
- A digital camera back, Phase One Studio Kit with software. Capacity up to
2,500×3,571 (8,9 million) pixels per colour. An ordinary VGA-screen
(640×480 pixels) shows 307,200 pixels. The camera back can provide files up
to 25 MB
- A Pentium PC, 200 Mhz, 96 MB RAM, 3 GB fixed drive
- A CD-ROM recorder with software
- Adobe photoshop
- ALEPH, the library software used at DNLB
- Standard software is used as well, e.g. for writing this text
Use of the software
Contents
- Adobe Photoshop
- Adobe Photoshop is used for changing the size of the pictures and for
converting to the .JPG format. The macro function, Actions, is used when
working with directories.
- Aleph
- We have chosen to use Aleph's facilities to the full, and to make use of
that program's WWW-interface for the picture database. When searching in
Aleph the pictures will be shown with relevant information (the name of the
plant, the number of the plate, etc.). Technically it would have been
possible to make more elaborate pages, but the result would not be worth the
extra work. Because the picture database is meant eventually to contain more
than pictures of plants, general descriptions have been given to the various
fields . We hope that this generalization does not limit the usefulness of
the base when more digitized works are added.
The pictures
Contents
After the scanning the Flora Danica plates will be saved as .TIF-files.
Before being placed on the WWW-server these files must be reduced and converted
to .JPG-files.
The degree of reduction and the picture compression were chosen for practical
reasons. A slight impairment of the image quality is inevitable.
- Reducing picture size
- The original pictures are reduced to about 20 % of the normal width of the
picture. Such drastic reduction is necessary for the pictures to have a size
that permits a meaningful showing on a 1024×768 screen. You will also be
able to see most of the picture on an 800×600 screen, whereas the
resolution on standard VGA screens (640×480) is so low that in most cases
only about half the picture will appear on the screen.
- Picture compression
- Picture compression is done by means of .JPG. This format is one of the
most popular these days. It reduces the file size appreciably without
impairing the image quality to any great extent. To take an example, the
globe-flower (Trollius europaeus (L.)) will take up approx. 12 MB in
the .TIF format but only 58 kB in the .JPG. This means less waiting when
downloading.
Saving in the .JPG format you can choose between many degrees of
compression. High compression produces smaller files, but also a drop in
image quality. Because image quality is of the highest importance for this
project we have chosen a low degree of compression. "Thumbnails"
on the other hand are compressed to the limit, resulting in files half the
normal size.This means a lot when browsing as 20 thumbnails have to be
downloaded on every page.
The original files
Contents
The original .TIF files are saved uncompressed on CD-ROM disks. This makes it
possible to make new and larger pictures to display on the WWW when in a few
years the average screen has a higher resolution than today. A CD-ROM contains
between 30 and 40 files. The reason we have chosen not to use any degree of
compression is partly that the files then can be read directly from the CD-ROMs,
and partly that we avoid the risk of loss of data.
Colours
Contents
To ensure the best possible likeness in colour with the original plates these
will be published in 16 million colours. How the many colours will appear on the
receiving screen depends entirely on the quality of that screen. If 256 colours
have been chosen, or the screen is badly adjusted the colours may differ a great
deal from the originals.
Torsten Schlichtkrull, ts@dnlb.dk
© Copyright 1998 Danmarks Natur- og Lęgevidenskabelige Bibliotek
