3.4 Technical Analysis of OpenLayersTop3.2 Smart Map Browsing3.3 Requirements Analysis



3.3 Requirements Analysis

One of the more surprising observations in Section 3.1.4 is the extraordinary continuous zooming feature of p.mapper. OpenLayers on the other hand is convincing in almost all other areas, and in addition has one of the most active communities in the Free web mapping area. Furthermore, using the new term Smart Map Browsing (see Section 3.2) as a guide, there is great development potential for OpenLayers and animated zoom processes. A zoom feature similar to the one featured in p.mapper would be an ideal addition to OpenLayers.

Based on the reasons stated above, the Free web mapping application OpenLayers supplemented with a novel add-on animated zooming feature was selected for the practical part of this thesis. This section details the exact requirements for this type of add-on feature.

3.3.1 Purpose

The purpose of the practical thesis portion is to implement the Smart Map Browsing feature animated zooming into the Free mapping application OpenLayers.

The main purpose of the extension is to assist during navigation, so as to ensure the user's orientation during the zoom process.
Note: Empirical measurements will not be conducted, therefore a measureable enhancement is not possible. However, the definition of Smart Map Browsing implies that this extension would have a positive effect on usability. In comparison to non-animated zoom processes (whereby the map »jumps« into the desired zoom level), an animated continuous zoom process would noticeably improve the user's orientation, which would likely also lead to greater acceptance by the community. A general consensus regarding the attractivness of this extension is evidenced by the mailing list discussions on animated zooming.

3.3.2 Must-Have Criteria

The functionality of an application (as seen from the user's point of view) is described by the following Must-Have requirements:

  1. It should be possible to freely move the zoom slider on the zoom bar by holding down the left mouse key. This means implementing the following application scenarios:
  2. As soon as the user selects the desired zoom level (by releasing the left mouse key), the hitherto scaled bitmap tiles (along with all activated overlays) are redrawn.

3.3.3 Should-Have Criteria

The should-have criteria for the animated zooming feature are defined as follows:

  1. Full animated zooming support for all layer types available in OpenLayers.
  2. Zoom Animation with Zoom Bar (buttons)
  3. Double-click Zoom Animation
  4. Zoom Animation with Mousewheel
  5. Zoom Animation with Zoom Box
  6. Zoom Animation with Keyboard

The following is valid for each zoom animation:
The animated zoom process occurs automatically within a defined time period. The zoom slider moves in sync with the animation until the desired position (up or down) is reached. Once the map is at its highest/lowest zoom level, no additional zoom-out or zoom-in animation is possible. During the zoom animation the marker in the overview map adjusts itself continuously to the section of the main map. As long as the zooming animation is active, no additional zoom processes can be activated.

© June 1, 2007 | Emanuel Schütze | some rights reserved.
This work is licensed under the Creative Commons License Attribution-ShareAlike 2.0 Germany.

3.4 Technical Analysis of OpenLayersTop3.2 Smart Map Browsing3.3 Requirements AnalysisContentsGerman