Analysis with the Geodatabase in ARCGIS 8.1
February 15, 2001
Make sure that prunus\teach is mapped to the p drive in explore (not from arccatalog or arcmap)
Open ArcCatalog
Make sure you have connected to p:\classes\arc8\tooolsdata in arccatalog.
Copy the geodatabase in p:\classes\arc8\toolsdata (Test 1) to c:\temp. (be sure to copy the whole cylander….select it and drag it over to c:\temp. Note that the drag and drop seemed to work better than copy and paste.
Copy raster files also
**Remember that you can copy from arccatalog but not from the explorer interface (outside of arcgis). Remember from your old ARC/INFO days where you tried to do system copies and lost your info files. The same applies here. You need to do your moving of files in arccatalog even if it is slow.
NOTE: Analysis functions on a geodatabase are done in ArcMap, not ArcToolbox:
NOTE: SAVE YOUR ARCMAP SESSION BEFORE YOU EXECTUTE ANY OF THE WIZARDS (Things crash and bump you all the way out of arcmap)
Note: In ArcMap you can zoom to an area and save a bookmark of that zoom (so you can go there again)…You go to view, bookmarks to save, edit, and return to a bookmark. This is really slick. (for those of you who are tired of trying to find that spatial extent, getting it just right, only to lose it when you have to move to another extent.
Now back to the lesson:
Open ArcMAP
Create a new empty map. Change to not automatically turn on features when they are added to the map session. Go to Tools, then options, then application…turn off.
Add + the feature classes (click on geodatabase (Test1) and add the features located below that)
Add the raster data sets at this time.
Select tools, geoprocessing wizard
You can dissolve, merge, clip, intersect or union
Select tools, buffer wizard
Under tools, you can also do geocoding, add route events, and bring up the editor toolbar.
Today we are going to run through the example of last week and do this with a geodatabase. You will want to save your data into the geodatabase, not a shapefile.
Follow the instructions in last session class notes, except you want to do this in arcmap.
Try Clip, Buffer, Dissolve, Select, Overlay, Union. Try selecting subsets of data.
Note: we had trouble with the buffer command (when we tried to dissolve the overlaps)
Try to clip a feature set from the geodatabase with a coverage. Try and union a coverage and a feature set. (We haven’t tried this)
Open a table for one of your generated feature classes and run statistics (hint…select a subset of data, highlight the field (look for shapearea), and right click on the mouse.)
Part 2: Editing:
Turn on hjaveg_polygon. Highlight it. Zoom into an area on the map where you can make edits. Find the editor toolbar. *go to View, toolbars and click on. Or look for the pencil with 4 squares connected by lines.
Click ‘Start editing’
You get several buttons that become active. You have a selection tool, a pencil, a task bar, and a target bar.
The target toolbar is for you to indicate what feature you want to edit. (select hjaveg_polygon.) The task toolbar gives you a choice of tasks.
For this first example, we are going to do ‘reshape features’
Select reshape features
Go back to the main editor tab, pull down and select SNAPPING.
Set the snapping environment to edge of hjaveg_polygon.
Now you need to select a polygon to edit. You are going to try and split the polygon into two parts. Use the select tool. The polygon will be highlighted in blue.
Then use the pencil to split the polygon. Start outside the polygon and use the left button of your mouse and click to make a line. You can make a straight line, or bent, depending on how many intermediate points you make. Bring your line outside the polygon and double click on the left mouse button to end the line. Try right clicking instead of the double left click. You get a menu of choices. Your polygon should be split in half.
If you don’t like the new polygon, try going to the edit button on the top of arcmap, and hitting the undo last move button. You can also drag your selected polygon around, rotate it, look at the table and see how the area has changed (hint…look at the whole file). Try some of the other options in task: (try cut polygon features)…
Try some of the different pencils. *try the trace (it’s pretty cool)
You can save your edits (under the editor toolbar). You might want to INTEGRATE your data (look up in Help).
Optional: Add a digital orthophoto to the map and try to do heads up digitizing.
Look in P: for mckenzi_dq
When you are done editing, you need to go to the Editor button and hit stop editing.
This will take you out of edit mode. We just scratched the surface with the editing tool. Someone else could look at the manuals and go into more depth.
Another area to investigate is the Edit Cache. Look it up in the ARCGIS help. It is supposed to make editing faster as long as you don’t change your spatial extent. Using this should increase your performance.
Part 3: Extensions
It appears to me that you have to have SDE to import raster data into a geodatabase.
You can try going to arctoolbox and doing the import raster to geodatabase. I did this and got error messages and it kept asking for a SDE database to put it into. This is an area where more research is needed.
However, you can use the spatial analyst extension to do raster processing (outside of the geodatabase).
Go to View pull down, and toolbars. Turn on the extension toolbars (spatial analyst)
Go to spatial analyst, use surface to create a hillshade of lat_10 (345, 45)
Go to spatial analyst, use surface to create a 50 meter contour shapefile of lat_10
Look at the other functions available in spatial analyst.
Other extensions of interest are:
3d analyst (use ArcScene)
Try out the contour button. (first button to right of layer pull down)
Geostatistical analyst: (For some reason, this is not showing up on the computers in Richardson 203. I’ll be doing some checking into this)