Saving your work with Arc GIS 8.x
WARNING: Reading and understanding the information in these pages and following these instructions will help prevent 90% of the difficulties you are likely to face in working with Geog 460 ArcGIS 8.x labs in the Sherman Lab. 'Lost' work that is turned in past the established due date is still late (see syllabus).
This handout describes several subjects related to the computer network in the Sherman Lab. Being familiar with these fundamentals will help to make you more proficient in use of the computers and prevent common problems leading to losing your work. It is very important that you read this handout carefully and follow the directions to ensure that you do not lose any of your valuable work. ArcGIS 8.x is complex and it can lock up or crash from time to time, especially if it is overloaded with processing and display tasks.
Remember: Configure ArcGIS to save to your work space, save early and save often!!!!
Although the lab assignments in this class are designed so you do not need the results of a prior lab to complete labs later in the course, you will want to save your labs for the following reasons:
1. ArcGIS can crash at any time.
2. You need to leave the lab and resume your work at another time
3. As a reference in preparing for the exam.
4. As a reference for compiling a portfolio.
The " P:\Stedents\YourUWNetID\
GEOG460" is a network drive
directory where you can do your work. You have 300 MB
upper limit, please stay inside your limit.
The "D: drive" is the zip drive in your PC. You must supply your own diskettes for storing your labs and/or project. Keep several disks on hand in case your work will not fit on one disk and so you can maintain a backup in case of diskette failure. For the purpose of consistence and clarity, you may want to create the same directory/folder as you do on C: drive, i.e., backing up your files to "D:\temp\460\My_UWID" rather than simple to "D:\".
The " P:\geog460Aut02\Data" folder
and "Q:\ drive" are "read only" drives
and you CANNOT write or save files there. This protects the database for this
class from becoming corrupted by overwriting altered/processed data layers
created during labs. The data and project files you need to initiate lab
exercises for Geography 460 are located on the P: drive and Q: drive in the
following paths: R:\AVDATA, P:\geog460Aut02\Data, and Q:\BI_DATA.
If there are congestions in network (particularly when you do bigger
exercises/project later on), it is more preferable to work from files
resident on "C:\temp\460\My_UWID" on your local computer because it
is faster. But
this way you need to copy both the project file, the source data, and the
intermediary results back to your network folder, because you can’t be
ensured to use the same computer and files kept on C:\temp may be erased.
III. ARCGIS8.x and Saving Files
AG8.x deals with three primary types of files: project files, layer files and data sets. The Project files have a .mxd extension. Project (.mxd) files are basically files that describe what data sets are being used in each Data frame, how the data is symbolized, how Data frames are organized in the layout, and what data operations have been performed.
Data sets are stored separate from project files. This way, many projects can access the same data sets. This reduces storage needs and maintains consistency in your data. ArcGIS data sets consist of multiple file types identified with different extensions, including (but certainly not limited to): .lyr (Layer) .dbf (Dbase), .shp (Shape), .vat (Value attribute table), all of which can be recognized in ArcCatalog.
Layer files keep the
data source shortcuts and symbolization settings.
As you work with data in ArcMap, the program creates many, potentially 1000's, intermediary and temporary files. These files are written to one of two places: the default working directory or a working directory that you specify. When you save a project, the only file that ArcMap writes is the main project (.mxd) file. This file is separate from the original data source and the intermediary files. If you try to start a saved project without all the files created by ArcMap during previous work sessions, ArcMap will display a red exclamation mark “!” with the layer name and the layer is not displayed. In this case you’ll need to reset the correct data source. If you do not know where they are (on the C: drive for your machine or the machine you used last), then you will be unable to open your project with the work you may have already done. This is the same as having lost your work during a crash or lock up.
Simply using the 'Save As' function will not guarantee that you save all the files needed to reopen your project in progress. The following system of creating folders, setting save directories, and folder transfers will permit you to save ALL the files you need to reopen a saved project.
IV. Folder Management and Saving Your Work
1. Each time you initiate a new lab or project, you should create a folder that will contain all the files you need to make that project work. This folder needs to be on the P:\ drive to be considered permanent.
2. You must tell ArcMap that you
want all your work to be saved to your working folder, which should be "P:\Students\My_UWID\GEOG460". ÊWithin this
directory, it may be a good idea to create a specific folder for each lab
exercise. To set
a fixed location for Spatial Analyst intermediary results, use Spatial Analyst
-> Options -> General tab, type in or navigate to the location.
3. If you are working on C:\ drive for more speed, when you are done with your work, you must transfer your working folder to your storage space on "P: drive". If you do not save to a diskette then any work you leave on the "C:\temp\460\My_UWID" has a high possibility being erased.
4. Use “Full
path” vs. “Relative path”
These paths are data
source locations relative to the project file (.mxd)
location. If you need to transfer back and forth your project with data, you’d
better use “Relative path”.
For example, if you
copy the project file and the data on your zip disk and read them in the
library, ArcMap will not recognize a P:\ drive if you
use full path, so the data can’t be found. If you use “relative
path”, as long as you keep the file structure in a folder (in our case
the GEOG460 folder), everything will work fine.
To set “Absolute
path”or “Relative path”, under ArcMap, go to File -> Map properties -> Map source
options.
If any of this does not make sense or you do not understand, YOU MUST ASK YOUR TA FOR HELP.
Work left on the C: drive will be erased.
Attempting to work from a diskette (the D: drive) rather than a working folder on the "C:\temp\460\My_UWID" may cause the diskette to fill and ArcView will crash causing a loss of work.
|
Summary of File Locations |
|||
|
P:\GEOG460AUT02\ |
Exercises, ArcMap Projects (.mxd's) |
Server hard drive |
This data always stays on the server, and is read-only |
|
Data |
|||
|
Q:\BI_DATA\ |
More data |
Server storage space |
This data always stays on the server, and is read-only |
|
P:\Students\My_UWID |
Working
folder |
Server storage space |
Use this space, in addition to your zip diskette, to back up your files |
|
C:\temp\460\My_UWID\ (optional) |
Temporary
folder |
Local hard drive workspace |
can add speed, but need initial and final transfer |
|
R:\AVDATA\ |
Project source data |
Server hard drive |
This data always stays on the server, and is read-only |
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