The 217-MAP object is the top level object of the data sub-model associated with exchange of cultural data and other items which are to be displayed on a map. Usually, these items are useful for exploration but need not be directly connected to an exploration item such as a seismic line or a well. This sub-model is primarily concerned with transfer of text items, symbols, points, and lines associated with items one wants on a map such as a town, a lease boundary, a river, national boundary or a shoreline.
Data describing maps, along with all of their contents can be quite large. Since systems using Geoshare often have limited hardware and software capabilities, guidelines are needed to help developers break up datasets into pieces small enough to be handled. Geoshare provides for such decomposition by allowing parts of a larger dataset to be placed in each of a number of logical files. Map data can be broken up by placing a limited number of maps into each logical file, or even breaking a single map into multiple logical files, although there is currently no way to identify the resulting fragments as being part of the same map.
For a Geoshare dataset containing just map data, the number of maps in a logical file should not exceed the following guideline based on the amounts of associated data of various types:
where A is the number of map annotations, L is the number of polylines (regardless of the number of individual points making up the polylines), P is the number of map points, S is the sum of the number of map symbols. If this value comes up e.g. 2.7, then it is best to limit the number of maps to 2 per logical file.
Additional information on this subject can be found in the section 'Logical Composition of Large Datasets'.
Label |
Restrictions |
Comments |
Optionality |
Units |
|
|---|---|---|---|---|---|
| SOURCE | C=1, | R=ASCII | 1 | ||
| OWNER | C=1, | R=ASCII | 1 | ||
| CARTO-PROJECTION | C=1, | R=OBJREF | 2 | MAND | |
| LOCAL-DATUM | C=1, | R=ASCII | 3 | ||
| X-MIN | C=1, | R=FDOUBL | 4 | MAND | U |
| Y-MIN | C=1, | R=FDOUBL | 5 | MAND | U |
| X-MAX | C=1, | R=FDOUBL | 4 | MAND | U |
| Y-MAX | C=1, | R=FDOUBL | 5 | MAND | U |
| Z-UNIT | C=1, | R=UNITS | 6 | ||
| FEATURES-ON-MAP | R=OBJREF | 7 | MAND | ||
SOURCE C=1, R=ASCII OWNER C=1, R=ASCII
The name of the source and owner of the data in the map. The source is the business associate or algorithm responsible for the content of the data. The owner is the business associate that has the authority to create, view, update, or delete a particular data item and also has the authority to grant/revoke other business associates these same rights.
CARTO-PROJECTION C=1, R=OBJREF MAND
A reference to a 217-CARTOGRAPHIC-PROJECTION object for the map.
LOCAL-DATUM C=1, R=ASCII
The name of a feature used as the datum reference for latitudes and longitudes.
X-MIN C=1, R=FDOUBL MAND U X-MAX C=1, R=FDOUBL MAND U
The extent of the map in the X dimension. In case the LATLONG cartographic projection is used, longitude limits may appear in X-MIN and X-MAX. The unit used must correspond to the distance or angular value used.
Y-MIN C=1, R=FDOUBL MAND U Y-MAX C=1, R=FDOUBL MAND U
The extent of the map in the Y dimension. In case the LATLONG cartographic projection is used, latitude values may appear in Y-MIN and Y-MAX. The unit used must correspond to the distance or angular value used.
Z-UNIT C=1, R=UNITS
The unit associated with vertical Z-axis measures on the map.
FEATURES-ON-MAP R=OBJREF MAND
A list of references to 217-MAP-OBJECT objects to be displayed on the map.
Send questions and comments to
Jim.Theriot@POSC.org
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