A study of management system of the ground control point database for ROCSAT-2 Remote Sensing images
Database Management System
To describe a GCP, two types of attributes are required, such as space and image attributes (Lee 1998).
For space attributes, they are source, built date, name of point, number, level, geographical coordinate,
location, map reference, code, and description. For image attributes, they are sketch, photo, and image
chip. The attributes are summarized as table in Table 1 and 2. The typical examples of attributes are as
Table 3 for codes, as Figure 1(a) for sketch, as Figure 1(b) for photo, as Figure 1(c) for image chip.
All attributes of GCPs are managed by a database system, for example Sybase, or Excel. The database
system shall provide functions of edit, I/O, display and query to manipulate the attribute. Those functions
can be programmed with some tool, like MicroSoft Visual Studio or Java.
Query is very useful function for the system. The query conditions can be any space attribute. The user
can also inquire interactively from a map on the CRT, such as Figure 2, with sub - functions of enlarge,
reduce, and shift. The area of query can be a point or rectangular area.
The results of the query are displayed on the CRT. Space attributes of a GCP are displayed as Figure 3.
Further query of image attributes is initiated at the bottom of the display. For example, one of the three.buttons, the sketch button, at the right of the bottom s is pushed, the drawing of the sketch will be popped
out as Figure 4.
Table 1. The summarization of GCP space attributes
| Attributes |
Summarization |
| Name |
To name the GCPs according to location and characteristic. |
| Number |
To set up a serious number to each GCP |
| Level |
To designate the GCP Level according to the accuracy of GCP geometric coordinates
. |
| Coordinate |
To record the GCP's space coordinates that including TWD67 and WGS84 coordinate systems. |
| Built time |
To record the GCP built time. |
| Source |
To record the survey method of GCP coordinates . ( GPS survey, Digitizing from map
…) |
| Location |
To record the county where the GCP located . |
| Map reference |
To record the map number (1/5000) that the GCP located.. |
| Code |
Using two characters to represent the features of the GCPs. |
| Description |
Using concise words to describe the GCP's characteristic. |
Table 3. The example of space attribute for codes
| Attributes |
Summarization |
| Sketch |
Using image software to draw the sketch of GCP according to description attributes. |
| Photo |
The ground truth photo of GCP taken by digital camera. |
| Image chip |
The image chip of GCP are extracted from ROCSAT-2 simulative image
. |
Table 3. The example of space attribute for codes
| Code |
Illustration |
| BC |
Center of the bridge |
| RI |
Intersection of road |
| LW |
Interface between land and water |
| VE |
Very sharp point |
| HC |
Corner of house |
| RS |
Route sign |
| MR |
Turning point in mountain road |
| FI |
Intersection of ridge |
| RC |
Corner of the levee |
Edit functions of the system provide functions of manipulation, such as update, delete, new, authority, and.history of records.
I/O functions provide data import of other data format, such as Excel, dBase and image import of photo,
sketch and image chip. I/O functions also provide data transfer and printout. Data can be reformatted as
Excel or dBase and required attributes to send to other server to process.
Figure 1.The typical exa mple of GCP database image attributes
Figure 2. Image map on CRT
Figure 3. The query result of GCP database on
CRT
Figure 4. The display of sketch on CRT
