When you import coverages and INFO tables into the geodatabase, ArcGIS automatically converts the coverage geometry and fields to types used by the geodatabase. This section describes how coverages are converted into geodatabase content.
All feature class types within ArcInfo coverages convert to one of four fundamental geometry types in the geodatabase (points, lines, polygons, or annotation). Each coverage feature class becomes a new geodatabase feature class. For example, point feature classes, tic feature classes, and node feature classes all convert to separate point feature classes in the geodatabase. The following table illustrates how feature class types convert to geodatabase geometry types.
| Coverage feature class |
Geodatabase geometry |
| Point |
Point |
| Arc |
Line (polyline) |
| Polygon |
Polygon |
| Node |
Point |
| Tic |
Point |
| Region |
Polygon |
| Route |
Line (polyline) with measures |
| Annotation |
Annotation |
All attribute types in coverages and INFO tables convert to field types in the geodatabase. Coverage and INFO table items convert based on a combination of their type and their width. For example, an item of type I can map to a short integer, long integer, or double, depending on its width. The following table summarizes how items convert.
| INFO item type |
INFO item width |
Geodatabase field type |
| B |
4 |
Long integer |
| C |
1–320 |
Text |
| D |
8 |
Date |
| F |
4 |
Float |
| F |
8 |
Double |
| I |
1–4 |
Short integer |
| I |
5–9 |
Long integer |
| I |
10–16 |
Double |
| N |
1–9 |
Float |
| N |
10–16 |
Double |
Coverages contain several fields that are relevant to the coverage data model only and are not maintained by the geodatabase; therefore, you should determine if you want to import them.
The following is recommended in most cases:
- When importing polygon or point coverages, don't import <cover#>, AREA, or PERIMETER.
- When importing line coverages, don't import <cover#>, RPOLY#, LPOLY#, FNODE, TNODE, or LENGTH.
- If the coverage you're importing doesn't use the <cover-ID> field to relate to another table, don't import this field.
When you import shapefiles and dBASE tables into the geodatabase, ArcGIS automatically converts the shapefile geometry and fields to types used by the geodatabase. This section describes how shapefiles are converted into geodatabase content.
The geometry types for points, lines, and polygons in ESRI shapefiles are very similar to the corresponding geodatabase feature class types. Therefore, importing shapefile datasets into geodatabases is relatively straightforward.
All feature types in shapefiles convert to geometry types in the geodatabase, as denoted in the following table.
| Shapefile feature class |
Geodatabase geometry |
| Point |
Point |
| Point M |
Point with measures |
| Point Z |
Point with z-values |
| Polyline |
Line (polyline) |
| Polyline M |
Line (polyline) with measures |
| Polyline Z |
Line (polyline) with z-values |
| Polygon |
Polygon |
| Polygon M |
Polygon with measures |
| Polygon Z |
Polygon with z-values |
| Multipoint |
Multipoint |
| Multipoint M |
Multipoint with measures |
| Multipoint Z |
Multipoint with z-values |
| Multipath |
Multipath |
Each shapefile and dBASE field type converts to a single geodatabase field type, except for the Number type field. The following table summarizes how shapefile and dBASE field types convert.
| Field type |
Field width |
Geodatabase field type |
| Date |
NA |
Date |
| String |
1–255 |
Text |
| Boolean |
NA |
Short integer |
| Number |
1–4 (decimals=0) |
Short integer |
| Number |
5–9 (decimals=0) |
Long integer |
| Number |
10–19 (decimals=0) |
Double |
| Float |
1–13 |
Float |
| Float |
14–19 |
Double |
| Number |
1–8 (decimals>0) |
Float |
| Number |
9–19 (decimals>0) |
Double |
When you import computer-aided drafting (CAD) data files into the geodatabase, ArcGIS automatically converts the CAD geometry and fields to types used by the geodatabase. See
Import from CAD (Conversion) to read how CAD elements are converted into geodatabase content.
If you have been a longtime user of ArcSDE, you may have legacy datasets in ArcSDE that need to be imported into the geodatabase. For example, you may have previously loaded data into an ArcSDE database using an ArcSDE command such as shp2sde.
Or, perhaps you have written a C program to load data that uses the ArcSDE C application programming interface (API).
The process used to add these existing ArcSDE datasets to the geodatabase is straightforward. It is not so much a process to import the existing dataset as it is one where you
register the dataset with the geodatabase.
Registering an existing ArcSDE data table in ArcCatalog
- In the ArcCatalog tree, right-click the table or feature class you want to register with the geodatabase.
- Click Register with Geodatabase.
Registering an ArcSDE layer or table adds an ObjectID field to the table. This field will be called OID for tables and FID for feature classes. If a field called OID or FID already exists on the table or layer, then another name is automatically added to the registered table.
Importing data to a personal geodatabase
When you import a feature class from an ArcSDE geodatabase into a personal geodatabase, any text fields that are greater than 255 characters in length are created as memo fields in Microsoft Access. Personal geodatabases interpret this memo field as a BLOB, and set the field length in ArcGIS to 2,147,483,647 characters. This could have implications if you later attempt to copy this feature class from the personal geodatabase to another ArcSDE geodatabase. Most database management systems do not support text fields of this length.
