topic Zoom level in ArcGIS JavaScript Maps SDK Questions

Zoom level

ShaningYu — Wed, 29 Jan 2014 14:54:27 GMT

In one of my Silverlight project, the zoom scale can go the scale about 1:100. However, in my JS application, I can only go to about 1:1000. Why there is so big difference? Is it possible for JS to get zoom scale as deep as that in SL without any programming setup? Thanks.

Re: Zoom level

JeffPace — Wed, 29 Jan 2014 18:44:22 GMT

In one of my Silverlight project, the zoom scale can go the scale about 1:100. However, in my JS application, I can only go to about 1:1000. Why there is so big difference? Is it possible for JS to get zoom scale as deep as that in SL without any programming setup? Thanks.

You can get down to tile level 19, which is 1:1128.497176

In silverlight you could "zoom" farther I guess, which is just a blur zoom (no more detail, just bigger pixels).

You cannot do this is JS

However, you can create a custom tiled service with more levels. Then when you create your map, either use this service first, or manually defined your LODs to include more levels

For example, we go one level further with our basemap to level 20 (1:564).

Re: Zoom level - Solved but ...

ShaningYu — Thu, 30 Jan 2014 10:15:57 GMT

jeff: Tested using your approach - I added the operation layer that needs go deeper before the basemap layer. Then it can go to the scales I defined in ArcGIS Server (e.g. 1:500 and 1:250), even much deeper. The problem remained is that when it is open initially, the basemap is not loaded till I check the map gallery. When a basemap is loaded, the operational layer becomes invisible. Do you have any idea to handle it? Thanks.

Re: Zoom level

JeffPace — Thu, 30 Jan 2014 11:46:04 GMT

The basemap is tiled and opaque. You can not see through it. If you render it dynamically you need to make sure you request png for it to be transparent.

Or, once you load your map with your operational layer first, reorder your layers so the basemap draws at layer 0

Re: Zoom level

ShaningYu — Thu, 30 Jan 2014 11:48:01 GMT

Jeff: I loaded the basemap as an ArcGISDynamicMapServiceLayer and then set its opacity. Then it works. Thanks.