A glimpse into Geodatabses with virtual campus
I am using Esri's virtual campus training to gain experience with geodatabases. This post will summarize general concepts that I learned, challenges I encountered with ArcGIS (hopefully with solutions as well) and any key terms defined through this learning experience.
There are many different types of data formats that are compatible with GIS. However, geodatabases are the native form for data storage and provide advantages such as all data is centralized, ease of data migration, high data integrity, and multiple layers of images can be displayed as one.
The three basic types of geodatabase are personal, file, and multiuser. As the names suggest, personal geodatabases are smaller and typically used for one person projects. Where as file and multiuser geodatabases are much larger and allow multiple people to edit a database at the same time.
When you are building a geodatabase from scratch you must first design the outline/structure that the data will reside within. Think of this like the blueprint for your geodatabase because it outlines all the different areas you will need to fill with information. The blueprint will include feature classes, feature datasets, table/nonspatial data and stand along features (whatever it is that best presents the question you are answering with this ArcMap).
Next step: putting data into your blueprint. The commonly accepted forms of data: CAD, dBASE, INFO tables, Coverages, Shapefiles, Text files, and raster. Excel files are accepted but only as read only files. You can put data in your geodatabase through several different tools: importing, loading data, loading objects or creating your own data. When uploading data make sure to take into consideration coordinate system, resolution, and data quality. After you upload the data, you can assign geometry types and styles for the data. The basic geometry types are point, multipoint, line, and polygon.
After you upload you data, voila! You have a geodatabase that is now accessible for you to begin creating ArcMaps from the data you uploaded.
ROADBLOCK: Creating a feature class
Every time I ran through the steps to create a new feature class for 'Roads' ArcGIS gave me the following error, "Failure to create feature class because each grid size must be three times larger than the preceeding grid size."
After looking into this, I found out that this error occurred because for the feature class I was creating was a raster model not a vector model. Raster models require a coordinate system in order to be uploaded which I had not yet assigned to my geodatabase.
What is the difference between all of the file types available to upload into the geodatabase?
What is the difference between loading data and loading objects?
attribute: nonspatial information
feature class: geographic features with the same geometry type, same attributes, and same spatial reference
feature dataset: features within the feature class
geodatabase: container that stores spatial and attribute data
mosaic dataset: collection of raster data sets (images) as one seamless image, it has three layers: boundary, footprint, and image
schema: structure/design of the geodatabase (aka blueprint)