Welcome to the second issue of my on-line newsletter. The response to the first issue was great! Thank you for all your responses: I appreciated both the friendly and encouraging ones and the challenging ones. And thanks especially to those of you who forwarded the newsletter to your friends and colleagues. It means a lot to me.

- Part 1

In my last newsletter I addressed some of the generic technical and administrative issues relating to migrating ARC/INFO licenses from UNIX to Windows NT. In case you missed it, I addressed topics such as performance, reliability, and impacts on personnel and purchasing. In this issue I will begin to address some specific technical issues relating to the migration of ARC/INFO applications to Windows NT. I hope that this information will be useful, especially to those amongst you who are already tasked with such migration.

When migrating an application to NT, there are several broad activities that need to performed: setting user environments, setting application parameters, making UNIX-specific functionality work in NT, accommodating new drive and directory naming conventions, and making the migration as painless as possible. I will address each of these topics in order to convey the general activities required. Each installation will, of course, be different, and I invite you to write me with specific questions you have. In this first part I will address customizing the environment in both ARC/INFO and NT. In future editions of my newsletter I will also address replacing UNIX functions with AML and NT equivalents, and the general process of porting applications.

The user environment

The user environment consists of various system- or environment-variables that control where data is read from and written to, where programs are found, and so on. Some of these variables are set to default values by ARC/INFO during the user installation. Other variables are optional, and can be set after installation. For example, the background color (or canvas color) in Arcedit or Arcplot is black by default. However, it can be changed to white by setting an optional variable CANVASCOLOR. As another example, new fonts can be introduced to ARC/INFO using the AIFONTINDEX variable. Environment variables in NT can be set for a particular user of a particular PC, a particular user on whichever PC on the network is used, all users of a particular PC, or all users on the network.

Below is a list of environment variables for Windows NT. To read the complete reference, start ARC/INFO’s help system, press Search, then Index, and enter "setting,user-defined environment variables". My favorite variable is CANVASCOLOR, because I like the WYSIWYG appearance of black features on a white background, rather than on the default black background. Some users say that it puts a strain on their eyes, but then, how many users of MS Word, for example, change the background of their page from white to something darker? Not many. (By the way, you do that by going to Format | Background).

AICODESET · AICOLORFILE · AICULLING · AIFONTINDEX · ARCDYNAMICPAN · ARCINFOFONTNAME · ARCINFOFONTSIZE · ARCMAXBUFPOINTS · ARCMAXBUFARCS · ARCMEMSIZE · ARCPANZOOM · ARCTMPDIR · ARCTRANSACTIONSESSION · ARCUSEDRAWBUFFER · ARCWINDOWSTATS · APRESSTMPDIR · CANVASCOLOR · CROSSHAIRCOLOR · GRIDALLOCSIZE · OVERLAYALLOCSIZE · PRINTER · USEBACKINGSTORE

Application parameters

Application parameters consist of both parameters set by ARC/INFO for the general user, and by a specific ARC/INFO application for the purpose of running the application correctly. It is unfortunate that many users do not take sufficient advantage of the parameters available to them for customizing their environment. Fortunately, NT is more conducive to personal customization than UNIX, so I hope that more users will take advantage of these.

Generic parameters

Generic ARC/INFO parameters that may be set by the user include display settings (e.g. 9999 3 versus 9999 1), terminal settings (e.g. &term 9999), AML toggles (e.g. &PT &ON), Arcedit settings (e.g. shadeset colornames), Arcplot settings (e.g. library mybasemap), and so on. These are most easily placed in one of two types of special AMLs called <module>.aml (e.g. arcedit.aml) and .<module> (e.g. .arcedit). The basic logic is this: if the user wishes to customize Arcedit, for example, so that it always starts with a certain lineset or nodesnap distance, regardless of the project or start-up directory, then these parameters are best placed in a <module>.aml file. This file is best placed in a special start-up directory – I like to call it archome and to place it directly under C: or D: (e.g. c:\archome\arcedit.aml). When you install the User Setup for ARC/INFO, the installation script asks where the user would like to start up ARC/INFO. If the name of this directory (e.g. archome) is given, then any <module>.amls in that directory will be automatically executed when the module is started (i.e. arc.aml will run when ARC/INFO is started, arcedit.aml will run when Arcedit is started, etc.). If you want the official version from ESRI, start the help file, press Search and then Index, and enter "startup directory". The help file does not fully account for the flexibility the NT user has in starting ARC/INFO, however.

There are (at least) three ways to start ARC/INFO in NT: click on the ARC/INFO icon in Start | Programs | ARC INFO User 7.x; click on an ARC/INFO icon which has been added to the Start menu or to the desktop; or start a DOS shell window and type "Arc". The only method that is relatively likely to start in the start-up directory that was specified in the installation is the first one. Even then, if the user changes workspace prior to starting a module (e.g. Arcedit), the special AML will not start. So is all this customization worth it? Definitely! Let’s look at a method to accommodate the flexibility with which NT users can start ARC/INFO.

The first thing that you can do is set up two environment variables (either System or User variables – see above) called HOMEDRIVE and HOMEPATH. HOMEDRIVE would be the drive letter where your archome directory resides (e.g. C:\). HOMEPATH would be the path to your archome directory (e.g. archome). Then name your special AMLs .<module> (i.e. .arc, .arcedit, etc.) instead of <module>.aml (i.e. arc.aml, arcedit.aml, etc.). Then, wherever you start ARC/INFO, and by whichever of the three methods listed above, these special application environment AMLs will be executed.