Preparatory work on delineation of the major elements within the survey area from the aerial photograph, map or satellite images is strongly recommended.
For the scanning of the area the following sources could be collected:
- The most recent 1:10,000 scale base map including topographic and/or cadastral information, enlarged to 1:5,000 scale.
- Aerial photography prints at a scale of 1:5,000. Aerial photographs should preferably be ortho-photos or else geometrical properties need to be assessed.
- Digital outlines of the aerial photography interpretation held on a field computer.
- Maps derived from satellite imagery and image segmentation.
Mapping of elements in the field should be made in one or a combination of the following ways:
- In pencil, on sheets that are copied from the most recent 1:10,000 scale base map including topographic and/or cadastral information, enlarged to 1:5,000 scale.
- In pencil, on transparent overlay sheets placed on aerial photographs at a scale of 1:5,000. Aerial photographs should preferably be ortho-photos or else geometrical properties need to be assessed.
- Elements can be determined by photo-interpretation and used directly in the field.
- Digital outlines of elements can be held on the field computer.
Separate sheets or overlays are to be used for the mapping of areal and of linear elements. Points are to be mapped on the linear sheet, either as individuals, or groups.
Application of field computers:
Major advances are taken place in the application of field computers for the recording of habitat data. Various options are now available. It is important to note that all systems involve previous interpretation of different types of aerial photographs to produce parcel outlines which are then validated in the field. In the field season 2011 an Access based software was used, which is freely available. The form and database can be downloaded here:
It is strongly recommended that a photograph is taken including a GPS position to Illustration of the local conditions at the time of recording and as input for later quality assessment or for later recording.