Posts Tagged ‘settings’
Enabling and editing z-values
Problem: You need to load a shapefile that does not have z-values into a feature class that does
Some spatial data will store height information in a normal attribute table field, but others will store it in the feature geometry as a z-value. Using z-values increases the feature geometry from 2D (x and y) to 3D (x,y and z). ArcScene will automatically display 3D data using the z-values, and it will do so more rapidly than draping the data over a surface.
Because z-values are optional, you may run into a situation where you need to merge a layer that does not have them into a layer that does. For example, say you have a geodatabase holding tree locations along neighborhood streets. The height of the trees is stored in z. Your surveyors have gone out and collected the locations of some additional trees in people’s yards, but they didn’t use 3D geometry. You need to load the new yard trees into the street tree feature class.
Right clicking and selecting properties in ArcCatalog confirms that the StreetTreePntZ feature class has z-values but the YardTree shapefile does not.
Trying to load the shapefile as-is will result in the error message.
One solution: you could run ET GeoWizards Point to PointZ conversion on the shapefile.
Another solution: Environment Settings! Import the yard tree shapefile into your geodatabase as a separate feature class. But before you press the OK button, press Environments… right next to it.
Expand General Settings and under Output has Z-Values, change Same as Input (the default) to Enabled.
Now you will be able to load the z-enabled yard tree feature class into the StreetTreePntZ feature class.
The z-values for your newly loaded features will be 0. You can edit z values in ArcMap by starting an edit session, double clicking on each feature (to turn it into a sketch) and then opening the Sketch Properties dialog from the Editor toolbar.
In the future I will write an entry about visualizing these cool 3D features in ArcScene.
Tags: 3D, data loader, settings, z value
Adding file size and date modified to ArcCatalog
The problem: You need to discover the file size of an individual feature class within a geodatabase.
In the world of shapefiles, it was relatively easy to do this. You could open up Windows Explorer and add up the sizes of the component shapefile parts:
.dbf = attribute table
.shp = feature geometry
.shx, .sbn, .sbx = various spatial indicies
.prj = projection (optional)
.xml = metadata (optional)
When we migrated into personal geodatabases, you could at least see the size of the entire database by looking at the Microsoft Access .mdb file. You couldn’t drill down into individual feature classes, however. Then, when the file geodatabase came along, things got even worse. The characteristic feature of this data type is storage as file folders. And yes, the file geodatabase looks like a folder in Windows Explorer. But the contents of that folder are unintelligible.
The image below shows how these three most commonly used data types appear in Windows Explorer:
A peek inside the FileGeodatabase folder:
ArcCatalog, the file navigation system specifically for GIS data, is clearly the superior option here. However, just like with Windows Explorer (where you have to switch to detail view to see more than a list of thumbnails) it needs some tweaking before you can get the information you want out of it.
Here’s how: Go to the Tools menu and select Options, then the Contents tab. This will give you a list of the details that show up on the Contents screen when you are navigating through your file system. Name and Type are the only ones checked on by default. You will at least want to add Size and Modified.
Note: Date modified is useful to display for so many reasons, not the least of which are
- Gives a ballpark idea how current the dataset is, if you don’t have that information elsewhere
- Helps you differentiate between different versions that may be named the same thing
- Sorting by date modified is a one click way to gather together everything you were last working on
While you’re there, take a look at what else is available. The settings you select here will remain every time you open up ArcCatalog. Ever since I stumbled upon this, it is one of the first things I do when moving to a new machine.
I’ve taken ESRI’s USA major roads data and saved it into a shapefile, personal geodatabase, and file geodatabase. With these new settings, here’s how they appear in ArcCatalog’s Contents screen.
This is a good place to point out the advantages of using file geodatabases. As you can see, they use dramatically less space to store the same amount of data. This means faster load times, as well. The other two won’t be going away any time soon: Shapefiles are widely used and good in a pinch, and personal geodatabases are nice if you like using Access to edit attribute tables. But for long term file storage, file geodatabases really are the way to go. As a bonus, you can compress them as read-only, which saves even more space.
Tags: geodatabase, settings