Feature list

This is my attack on sorting out Web-based map viewer features. Once I have implemented a sample site at each level I can add links here!

My basic premise is this: Keep it simple. To be useful a map viewer needs to have enough control for a given application and no more; extra controls just make viewers confusing. When designing a map server application, first define the target audience. To serve multiple maps to many audiences, don't pile on extra features, set up different viewers.

For each selected application, choose the level of control required and implement only those features. Always always make the defaults useful.

Always use the right gadget: for example, if you have several raster layers, only one can be visible at a time, so allow selecting only one at a time by using radio buttons.

A comment on popup windows. I find popups to be distracting; for results of an identify tool, MAYBE okay. For things like legends? No. The extra window always gets in the way or ends up hidden behind the main window. Fit the legend into a frame in the main window. A tabbed interface is a better option if there is not enough real estate for multiple text areas.

Under no circumstances should you ever see a line that says "this page best viewed with" and the name of a browser or screen res.

Basic

Three frames in one window. A large, large-scale map, a small reference/locator small-scale map, and a text area.

I like the idea of using scroll wheel or slider to zoom in and out, click to recenter, and drag to pan. Few if any additional controls; possibly a print-ready button.

Though the user cannot directly select layers, the viewable layers can change at different scales (eg single line streets at small scale, going to double line + buildings at large scale.)

Points of interest are identified with icons, hovering over an icon gives a text flag with more information. Icons can be hyperlinked.

Possibly there can be different selectable points-of-interest layers; used judiciously so as not to become confusing! Keep it simple.

Used for: public access sites usable by anyone. For example, a tourist map of downtown or park locator / trail maps. Geocoded locations for inclusion in other pages (eg The "map it" button to show location for a public meeting)

If you put this app in a kiosk (say, in the lobby of a hotel) , the kiosk owner could center the map on the location of the kiosk, then save that URL as the home page for the kiosk. Hitting the "HOME" button on the browser would take the user back to the hotel.

This site has a clean, simple interface: http://www.downtownbethesda.com/

Intermediate

In addition to the basic interface, this level has tools for performing selections both with text queries and graphically. It allows tabular display of query results.

It allows control of displayed layers; but the map designer should be careful to set the default settings so they are useful! Better to have multiple maps each with useful defaults than one interface with 100 available layers.

This level can have one or more "places" selection lists to set extent.

This level can have an additional tool bar. Icons select tool, hovertext shows name of tool.

Used for: Basic GIS apps for internal and more advanced publically accessible sites; for example, querying taxlots data.

Advanced

In addition to intermediate level,

Has linear distance and polygon area measurement tools.
Has markup tools for points, lines, and polygons.
Allows user/passwd login to save session including markup, extent, and queries Allows upload and download of layers as shapefiles.

Possibly a login option on an intermediate viewer activates the advanced features.

With enough access rights, advanced user could create a map by specifying layers from those available on the server, setting extent, and saving the session in a publically accessible directory. The user could then publish the URL for this session to allow other users to access the new map. The owner of the session could set the interface level to basic/intermediate/advanced.

Therefore the advanced user interface could be used as a design tool for maps used at all three levels. (Should there be a 4th "Map Designer" level??)

Used for: internal users; publicly accessible for special applications.

For example, could be used for planning applications where one user can upload a shapefile, and other users can add their own markup layers to collaborate or comment.

This site allows markup: http://yorkexplorer.york.ca/yorkexplorer/default.cfm