Map caching for beginners

re: Map caching for beginners

gena — Sun, 02 Sep 2007 08:56:24 GMT

Hi !

Can you plz add to this post some issues:

-How different cache parameters affect the performance of the generation process?

-What parameters (and how) affect the quality of the resulting cache?

For example, if the quality of the cache image is very poor, what may cause it:

symbology of the layer in mxd, size of tile, DPI value, type of display adapter, ...

Thanks.

Regards,

Gennady

re: Map caching for beginners

Canh Khuu Minh — Tue, 04 Sep 2007 03:23:35 GMT

Dear, Blog information is quite usefull. So I have copied and translated some items into my free Vietnamese GIS webpage (at http://www.mathgis.com) as GIS news. Thank you very much. Regards, Canh Khuu Minh (kmcanh@yahoo.com)

re: Map caching for beginners

sterlingdq — Tue, 04 Sep 2007 23:20:31 GMT

@Gennady- The topic "Planning a Map Cache" in the ArcGIS Server Web Help contains a discussion of different cache parameters and how to anticipate the creation time of your cache:

http://webhelp.esri.com/arcgisserver/9.2/dotNet/index.htm#manager/publishing/planning_a_map_cache.htm

In brief, antialiasing can increase the cache creation time, as well as choosing the multilayer cache type (fused is the recommended type). Also, the number of instances you dedicate to creating the cache makes a big difference. Your server computing power affects what you should set as this number.

As for the image quality of the resulting cache, it should look pretty similar to your original map. You may notice some loss of quality if you are using JPEG image format for the tiles and you have vector data in the map.

Sometimes it can look like you have lost image quality when you view the cached service in ArcMap. When this happens, it's probably because you are not viewing the map at the scale at which it was originally cached. Zoom the map to one of the cached scales and it should look better. The reason for this is that ArcMap resamples your cached images to fit the scale you are viewing, and if your map portrays vector data, the resampled image does not often look as good as the original image.

-SQ

re: Map caching for beginners

gena — Mon, 10 Sep 2007 14:21:03 GMT

Hi !

Thanks, I'll learn this "Planning ..." issue.

Updating your map caches automatically: The key to caching dynamic data

ArcGIS Server Development Blog — Fri, 04 Jan 2008 23:45:27 GMT

For the fastest performance of your ArcGIS Server map services, we recommend that you use map caching

re: Map caching for beginners

Robert — Mon, 07 Jan 2008 14:12:16 GMT

Can you please add to this blog posting how to combine data that is both static and dynamic in nature to achieve the best performance using caching.

re: Map caching for beginners

gg7aph — Fri, 11 Jan 2008 09:18:36 GMT

Hi, Is it possible to cache spatial bookmarks extents? Cacheing my maps FULL extent has dramatically sped up display - however, when I jump to my various bookmarks (within my web App) it displays slowly again.

re: Map caching for beginners

sterlingdq — Fri, 11 Jan 2008 15:38:42 GMT

gg7aph- This is interesting. Can you explain a little more about what these bookmarks are in your web app? Are you jumping to a certain extent on your map programmatically? If so, what call are you making to get the map?

-Sterling

re: Map caching for beginners

azdroik15 — Wed, 16 Jan 2008 21:28:01 GMT

I've read that you can overlay a map cache on top of another map cache or use a map cache and non-cache together. I guess I'm not sure why this would be useful instead of having just one map cache. Could you please give some examples as to why someone would do this?

re: Map caching for beginners

sterlingdq — Wed, 16 Jan 2008 23:00:23 GMT

azdroik- There are several reasons you might not want to include all of the layers in one cache. First, some of your data might change so often that it would not be worth the effort to create and maintain a cache. You could cache all of your other layers together and leave the changing, or dynamic, data as a non-cached service.

Another reason to create multiple caches is so that you can turn layers on and off. When you create a cache (of the default type "fused") all of the layers are included in one image and cannot be turned on and off. However, if you overlay two fused caches, you can turn those two layers on and off. In this case, the fused caches would act like group layers.

re: Map caching for beginners

ras — Wed, 16 Jan 2008 23:01:31 GMT

I can comment on why I use multiple caches and services. I have 3 fused caches (that all use the same caching schema/scales), and one non-cached. With fused caches you can turn the entire service on/off but not individual layers. My first (bottom) cached service contains topo maps, hillshades, and other simple base features (that are scale dependent - - i.e. the ArcMap project controls the symbology and what is shown at each level) My second, cached service contains more details Hydro data, including NHD. My third, cached service contains the management boundaries for the project. The forth, non-cached service are the labels only for the above management boundaries. This way they are dynamically places as the user zooms and pans.

re: Map caching for beginners

Borja — Tue, 16 Dec 2008 09:47:41 GMT

Hi all! Any comment about mixing in the same map service a cached service with the vector layers that have the business information of the application??. Those layers will be the source for query tasks and indentify. do you recommend to have 2 services, the first one with the non-cached service with the vector layers and the other one with the cached service?

re: Map caching for beginners

sterlingdq — Tue, 16 Dec 2008 22:50:00 GMT

@Borja- You can mix cached and non-cached services in an application. The reason most people do this is that they have some data that changes frequently that they need to see in real time.

You can still perform queries and identifies on cached services. The query or identify operation accesses the back end data on the server.

re: Map caching for beginners

Sandip — Wed, 29 Apr 2009 10:49:20 GMT

Hi, I have one question. In our project we have many layers out of which we do editing in only one layer. So my question is, can I cache all other layers except the one I am editing?