Frequently Asked Questions for USERS of the ArcView 3.x MassGIS Data Viewer

Q: When the Viewer first starts up I receive some error messages such as: "Did not find the men1 directory in either c:\viewer\data\ or d:\gisdata. Some data may not be available." What is happening?

A: The Viewer can't find some of the data that is specified in the environ.txt file. The environ.txt file is an ASCII file that is stored with the other Viewer files in the \data directory. The basic environ.txt that is distributed with the Viewer looks like this: 

ARCHOME=archome
AVLEGEND=legends
MEN1=men1

If you are using imagery then you will need one or more of the following lines in the environ.txt:
HALFMSID=images\halfmsid
OQ1SID=images\oq1sid
QUADSID=images\quadsid
COQ2001HALFMSID=images\coq2001halfmsid
COQ2001HALFMSIDM=images\coq2001halfmsidm
QUADSID=images\quadsid

This file does not have to be edited if you leave the data on the CD, or if you install the data in a directory called \gisdata\ parallel to the \data directory on your hard drive. However, the data can be moved elsewhere by subdirectory. If you move the MEN1 subdirectory to c:\massgis\stuff\men1, then you need to edit the environ.txt file to read: MEN1=c:\massgis\stuff\men1. You can move data onto other hard drives that you are networked to, and in that case you would edit the environ.txt to list the exact path to the data (however you defined the drive letter.). For example, if you mapped the drive letter "m" to another networked computer, and you installed the basin directory there, you need to edit the environ.txt file to read MEN1=m:\men1. 

The information in this file is read into ArcView at the beginning of your Viewer session and is valid for your entire ArcView session (regardless of which project you are using). If you edit this file, exit ArcView completely, or ArcView will not reflect your changes. 

The environ.txt file is only important for Windows users. Environment variables on the UNIX system are set through a user's .profile file or .cshrc, or other startup file. 
 

Q: When the Viewer starts up, I receive some error messages, the last one being: "AVArray: Index 0 not in range 0..-1". What does this mean?

A: This means that your ARCHOME environment variable is not set correctly. Make sure that the environ.txt file in the \data directory where you installed the Viewer lists ARCHOME as pointing to the place where the archome directory really is. Most users leave the archome directory under the \data directory on the hard drive where they installed the Viewer, so in that case the environ.txt should read ARCHOME=archome. The most common cause of this problem is that a user is using ArcView 2.1 or ArcView 3.0a in one of the Windows operating systems, and opened the av30mg2.apr project file directly. It is important that you open the "starter" project file which sets the environment variables. This starter project file opens the main project file. For ArcView 2.1 Viewer users, the starter file was called vstartup.apr, and for ArcView 3.0a+ Viewer users, the starter file is called sav30mg2.apr. 
 

Q: When the Viewer started up, it asked me for the drive letter of my CD drive. Where is this information stored?

A: That information is stored in a text file called cd.txt. This file is located in the same directory that the other Viewer files are stored in.  If you are using the full version of the Data Viewer, and you made a directory on your hard drive to store the Viewer called viewer, it is then in the c:\viewer\data directory. You can edit this file if your CD drive letter changes. 
 

Q: It seems that there is some data missing. Is something wrong?

A: It is possible that the error message you are getting is valid because the particular type of data you are asking for is not available for the area you are looking at. The 1:5,000 Wetlands and Soils layers, for example, are currently available for only part of the state. To find out if the data you are looking for is available you can use the "A" button on the viewer to bring up the list of theme menus and then choose "Status." There are several maps that can inform you what geographic areas of the state are lacking certain types of data.
 

Q: I’m having problems copying my files...

A: On rare occasions a CD leaves MassGIS with a problem. Give us a call and we'll see if we need to send you another copy.
 

Q: Can MassGIS help me with learning how to use ArcView?

A: At the moment, we don't have the resources to aid users extensively on ArcView itselt. However, in the docs directory ( /31/data/docs if you are using the ArcView 3.1.1+ Viewer version), you will find many helpful tutorial files in both Microsoft Word and Adobe PDF formats. You should also explore the help menu section that comes with the full ArcView software. Look under the "Help" menu at the upper right of your screen. 
 

Q: I can't seem to reproject the MassGIS data into another projection using the "View/Properties" menu choice. Why not?

A: Basic ArcView cannot reproject data that is already projected. MassGIS data that is distributed in Librarian format is projected in Mass State Plane NAD83 meters, so it cannot be reprojected in basic ArcView. If you have ArcView 3.1.1+, however, there is a free extension called the Projection Utility Wizard which was shipped with your ArcView software. This extension can project data from just about any projection to any other projection. 
 

Q: I have a copy of the MassGIS Data Viewer. Can I install it on multiple computers?

A: The MassGIS Data Viewer is in the public domain. You may install it on multiple computers, or alter it as you wish.
 

Q: I worked on the Viewer project for awhile and then saved it as myproj.apr. The next session of ArcView, I opened myproj.apr directly, but the project did not open correctly. Why is this?

A: The problem is that the starter project was not run, and therefore the environment variables were not set. One way to get around this problem is to always open the sav30mg2.apr file, close the main Viewer project, and then open myproj.apr. Since the environment variables are set for your entire ArcView session, you can close the main Viewer project and open another project and still have the correct environment variables.
 

Q: When I edit a table, I can't seem to get the last change I make in a cell to "take". Why?

A: ArcView seems to require that you move the cursor out of any cell that has been edited, or else it won't save the change you made in that cell. 
 

Q: When I use a UNIX machine, and make a change to a .dbf table and save it it doesn't get written to the disk (and the changes don't appear after I "Reset the Project"). Why?

A: The .dbf table is not always written to disk . If you suspect this is the case, you can force the table to be written to disk by choosing "File/Export". I would recommend writing the table out to a new name. For example, File/Export the zoominv.dbf table the test.dbf. Then delete the old zoominv.dbf and rename test.dbf to zoominv.dbf. If you File/Export a table to the same name the table can get corrupted.
 

Q: Give me a brief overview of how the Viewer can be customized.

A: There are ways to customize the Viewer that only require editing tables, and do not require editing scripts. For example, if the developer would like an initial extent of the Charles River watershed instead of the entire state outline, the zoominv.dbf table should be edited. The Active column value indicates which record is the initial extent. Place a "D" in this column for the record that you wish to be the initial extent. You should have only one initial extent. The same concept exists for initial themes. You can have one or more initial themes. These themes are marked in the themeinv.dbf table with a "0" (zero) in the Active column. Once any of the themeinv.dbf, zoominv.dbf, or inquiry.dbf tables are edited, you need to "Reset the Project" under the "View" menu. This reads the information from those tables into dictionaries. Once the project has been reset, you will see the results of your table edits in the "A" and "Z" buttons. 
 

Q: What are extensions and can I use them in the Viewer?

A: Extensions are self-contained modules that extend the functionality of ArcView and may be used in the FULL versions of the Viewer.  They may have one or several files (all with the same name but a different file extension).   They will only be seen by ArcView when they are in one of two places:

c:\tempor
c:\ESRI\avgis_30\arcview\ext32

When the extension file or files are put into either of these directories, the extension becomes visible in the list that is accessed through the File menu. 

When the extension is clicked 'on', the added functionality is available'; usually, new buttons and/or menu choices will immediately become visible in the ArcView GUI.  A brief description of the extension will appear in the extensions menu when you click on the name of the extension in the list.

There are a few extensions you will want to use often:
 - Spatial Analyst
 - Geoprocessing
 - Mr. SID image support
 - MassGIS Watershed Delineator

There are additional extensions that come with ArcView; these can be found in c:\ESRI\avgis_30\arcview\samples\ext, and there is help for all of these in the ArcView help.  There are also some very useful extensions available at the ESRI web site: http://gis.esri.com/arcscripts/scripts.cfm , where you can type in key words and search for something you may need (ex., 'latitude', or 'color'), and at many user web-sites.
 

Q: What documentation exists about the MassGIS Data Viewer?

A: There are many pieces of documentation - here are a few: 

What: install (.doc or .pdf) - information on installing the Viewer and MassGIS data.
Where:

On CDs under /31/data/docs and /data/docs

MassGIS Web Site: http://www.mass.gov/mgis/install.pdf

What: ex1pic (through ex5pic) (.doc or .pdf) - an introduction to ArcView and the Viewer
Where:

On CDs under /31/data/docs and /data/docs

MassGIS Web Site: http://www.mass.gov/mgis/gisedu2.htm

What: developr (.doc or .pdf) - explanation of Viewer's .dbf tables and how to extend the Viewer 
Where:

On CDs under /31/data/docs and /data/docs

MassGIS Web Site: http://www.mass.gov/mgis/devlp30.htm

Q: I installed the Viewer program. How do I now draw up the GIS data?

A: There are 2 ways to draw up data. The easy way to try first is to use the "A" button. The "A" button represents data that MassGIS has symbolized. If there is data in your view, it will appear when you pick a category off the list under that "A" button. The second way to add data to your View is to use the normal ArcView "Add Theme" button. You can use this button to draw up any MassGIS data or any other data that you may have. When using the Add Theme button you must know the name of the data file you wish to use and where it is stored on your computer. 
 

Q: I made a layout and want to bring it into another program (i.e. Microsoft Word). How can I save the map and do this?

A: First, highlight your Layout window. Then, go the the File menu and choose File/Export. Change what's displayed in the "List Files of Type" box in the lower left hand corner. This is the format your layout picture will be exported to. The formats provided are different depending on whether you are using ArcView for Windows or ArcView for the PC. Check which formats the application accepts that you want to put the map into. 
 

Q: Why do some data appear only at certain scales?

A: Some themes under the "A" button have associated minimum or maximum scales. This means that the data layer will not be drawn if the user is too far zoomed in or out for the data to make sense or be readable. For example, USGS quads will not be drawn if you are zoomed out more than 1:25,000. Some choices under the "A" button bring up 2 themes. For example, choosing "Infrastructure/Roads" will bring up a major road theme and an all-roads theme. If you are zoomed out and viewing a lot of area, only the all-roads theme's label will appear in the table of contents, and the symbols for the roads will not appear. Instead, the major roads theme's symbols will appear. It does not make sense to see every road when you are looking at the entire state, because not every road will be visible, and ArcView will spend a lot of time drawing. If you are looking at a small area, the all-roads theme will be drawn. 
 

Q: Can I edit the MassGIS data?

A: The MassGIS data distributed with the Viewer is in shapefile format. Once copied off the CD(s) they can be edited with ArcMap or a full version of ArcView . After copying the data off the CD ensure that the files are not set to be Read-Only.

Last Updated 11/20/2008
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