Creating a 3D globe cache from a 2D map cache

re: Creating a 3D globe cache from a 2D map cache

Brady — Thu, 31 May 2007 13:28:27 GMT

Please add the Map Cache tag to this post.

re: Creating a 3D globe cache from a 2D map cache

sterlingdq — Thu, 31 May 2007 16:33:56 GMT

Good suggestion. Some of our recent posts were missing tags and I've gone through and added them, including the one you mentioned.

Viewing cached map services (such as ArcGIS Online) in ArcMap

ArcGIS Server Development Blog — Mon, 02 Jul 2007 23:36:04 GMT

ArcMap allows you to view cached map services at any scale and projection. When you zoom in to a cached

Designing a map to overlay ArcGIS Online in a Web application

ArcGIS Server Development Blog — Tue, 07 Aug 2007 21:42:41 GMT

In November 2006, ESRI announced the public beta release of ArcGIS Online, a set of base map and reference

re: Creating a 3D globe cache from a 2D map cache

Carol Fackler — Fri, 07 Mar 2008 01:14:10 GMT

In step 4, Set the Cache Path, of "Create a globe document from the 2D service", you do not mention anything about changing the maximum size. 200 MB is not a very large cache size. What exactly does this maximum size refer to and does it need to be changed according to your cache size?

re: Creating a 3D globe cache from a 2D map cache

Sergey Naumov — Wed, 02 Apr 2008 15:47:03 GMT

Can you provide some information regarding the correspondence between levels of ArcGlobe disk cache (L09, L10...) and the 'Approximate scale' or 'Far-Near' LOD settings in 'Generate Cache' dialog?

re: Creating a 3D globe cache from a 2D map cache

Tamrat Belayneh — Thu, 03 Apr 2008 16:34:25 GMT

ArcGlobe is a paged display application that renders vector, raster and elevation data by tiling it into geographic divisions (faces) and also recursively at varying levels of details (LOD).

(see pages 3-4 of this whitepaper >> http://downloads.esri.com/support/whitepapers/ao_/TipsforDesigningInteractiveArcGlobeDocuments_J9264_.pdf).

The data cache is a persisted representation of this technology that allows organization of visualization pages into a hierarchical file based structure to facilitate paging in and out from disk.

The cache structure is consisted of 6 global faces, of which 4 are equatorial faces, organized in the form of folders named T0, T1, T2 and T3 covering the geographic regions 180°W to 90°W, 90°W to 0°, 0° to 90°E and 90°to 180°E and 45°N to 45°S, and 2 ‘polar’ faces T4 and T5 covering 45°N–90°N and 45°S–90°S, respectively (See graphics on page 2 of the above white paper). Each globe data cache consist of these folders (T0-T5) only if the data set covers/crosses the particular face. Hence a global dataset will have all the faces (T0-T5) where as a data set for southern California, for example, will only consist of T0 folder.

Each of the six major faces is subdivided into multiple tiles at different levels of detail. Each of this folder/s consist of visualization pages, or tiles, each again organized based on their geographic location (in the form of Rows and columns) and resolution (level of detail).

ArcGlobe supports many data types which could roughly be classified into 3 categories as far as the level of detail classification is concerned; these are Texture data (including feature data represented as rasterized), elevation and Vector (points, lines, 3D objects and billboard annotation). The level of detail values differ depending on the data type. However, each successive level of detail is derived by recursively dividing the previous level of detail by four.

In Arcglobe data cache structure, the level of detail for all texture data types begin with a L09. This folder corresponds to the lowest level of detail where as L30 correspond to the maximum level possible. Each level correspond roughly to the scales listed below. For raster/image data this levels are primarily driven by the cell size (resolution) of the data.

Elevation data follows similar pattern as imagery, the only exception is elevation data stars from level L08.

Data cache for imagery and elevation data can be generated from the lowest possible LOD value to the maximum supported LOD (based on the cell size). Hence the concept of ‘From’ and ‘To’ LOD values. Also note that when generating data cache you have also the option to generate partial LOD ranges as well.

The level of detail for vector data is solely driven by the ‘scale’ you’d like to visualize it. Note that vector data contains only a single level of detail, hence you’ll only find a single LOD folder for which the feature Level of detail (scale) value was selected for. For example, if you set the ‘Feature Properties’ value of a vector data to ‘Counties’ (or at a scale of 1: 156543), it will then generate data tiles at level of detail L06 (Vector LOD value in the chart below).

Raster LOD	Name	Scale 1:	Vector Lod	Resolution(meters)
9	Globe	10018754.17139462153829420444035, // 0	20000. , // 9
10	Continent	5009377.085697310769147102220175, // 1	10000. , // 10
11	Countries	2504688.5428486553845735511100875, // 2	5000. , // 11
12	Country	1252344.2714243276922867755550438, // 3	2500. , // 12
13	States	626172.13571216384614338777752188, // 4	1250. , // 13
14	State	313086.06785608192307169388876094, // 5	612. , // 14
15	Counties	156543.03392804096153584694438047, // 6	306. , // 15
16	County	78271.516964020480767923472190235, // 7	153. , // 16
17	Metropolitan area	39135.758482010240383961736095118, // 8	80. , // 17
18	Cities	19567.879241005120191980868047559, // 9	40. , // 18
19	City	9783.9396205025600959904340237794, // 10	20. , // 19
20	Town	4891.9698102512800479952170118897, // 11	10. , // 20
21	Neighborhood	2445.9849051256400239976085059448, // 12	5. , // 21
22	City blocks	1222.9924525628200119988042529724, // 13	2.4 , // 22
23	City block	611.49622628141000599940212648621, // 14	1.2 , // 23
24	Buildings	305.74811314070500299970106324311, // 15	0.6 , // 24
25	Building	152.87405657035250149985053162155, // 16	0.3 , // 25
26	Houses	76.437028285176250749925265810776, // 17	0.15 , // 26
27	House Property	38.218514142588125374962632905388, // 18	0.075 , // 27
28	House	19.109257071294062687481316452694, // 19	0.0375 , // 28
29	Rooms	9.5546285356470313437406582263471, // 20	0.0187 , // 29
30	Room	4.7773142678235156718703291131735, // 21	0.0094 , // 30

Hope this information helps.

Tam

re: Creating a 3D globe cache from a 2D map cache

Carol Fackler — Mon, 14 Jul 2008 20:40:17 GMT

The document you reference states, "Full data caching can be accomplished for any layer—exceptions being ArcIMS® and ArcGIS MapServer layers.", yet the above posts talk about creating a diconnected service. My higher number LOD (e.g. 20, 21, 22, 23) have empty folders in them. Is that because the cache for them has not been dynamically created yet. If I were to diconnect the 2D cache how could the 3D cache dynamically create those levels. Also is there a way to move 3D cache like you do 2D cache.

re: Creating a 3D globe cache from a 2D map cache

Tam — Thu, 17 Jul 2008 17:42:02 GMT

I refrenced the document above so users can understand the display and data caching mechanics of ArcGlobe. Please note that the above document refers to the ArcGlobe Destkop application and any exceptions mentioned there apply to ArcGlobe Desktop app. In any case, at the time the document was written (2004) Version 9.0 of ArcGlobe did not support full data cache generation of mapserver and ArcIms layers (which now it does). As to your other question, you state your globe cache seems to have higher LODs where it has some empty folders and you were wondering if the tiles were not yet dynamically created. yes that could be the case if you havent yet built the full cache. By 'if i were to disconnect the 2D cache' if you mean, if i removed the service that the 2D cache was based on, then, yes the 3D cache will not be able to generate any new tiles, and infact that could be the casue why those empty levels might have been created. Its always good practice, to generate the full data cache before disconnecting the 2D cache so as to not run into such issues. Regards,

re: Creating a 3D globe cache from a 2D map cache

Tam — Thu, 17 Jul 2008 18:51:01 GMT

Carol, Regarding your question, <"...Also is there a way to move 3D cache like you do 2D cache…”>, the answer is yes. In fact 3D caches (globe caches) are self contained in that the cache contains a layer file that references the data cache. So what this means is that you can copy/move a cache from one machine to another and you should be able to compose a new globe document (Open up an empty globe doc, from the add data command in arcglobe, browse and find the cache you just moved and descend into the cache folder. There will be a layer file that can be used to load the cache).Now the new document you just created has reference to the cache you just moved from its new location. At this point all you need to do is save your new globe document and use it to publish a globeservice. Remember that now the document contains caches that are now' disconnected' in that any refrence to the source data is disabled.

This technique is useful if you have built the full data cache for your globe layers before you moving/copying it.

At verison 9.3, this has gotten even easier; you can follow the followign workflow to accomplish the same as above;

* Lets say you generated your cache on your staging server, called ServerX. On this machine, you have the Globe document that you used for publishing your globeservices, lets call it GlobeDocX, and the caches for all the layers in GlboeDocX were generated and stored in the server cache location, c:\arcgisserver\arcgiscache\GlobeCache, assuming the default location.

* Lets also assume you want to move your globe document, GlobeDocX and all related caches, from ServerX, to another machine (say your deployment server), serverY and start a globe service based on these.

At version 9.3, all you have to do is copy your Globe caches and Globe Document to your new arcgis server GlobeCache location and start the service. When the service is started ArcGIS Server will inspect the content of the doc and start it in a disconnected manner if the data sources are not available. Continuing from the above hypothetical setting, here is how you'd do it:

* Move/Copy all your globe caches created for GlobeDocX to your new servers cache location, lets say ServerY, by default again its cache location will be @ c:\arcgisserver\arcgiscache\GlobeCache

* Copy the GlobeDocument, GlobeDocX, anywhere to your new Server (you can store it along with any other map/globe documents you may have).

* publish a new Service based on the document you just copied.

* When you start the service, ArcGIS server will inspect the globe document you just moved from ServerX, and determine if each layer has a corresponding data cache available for it in the data cache location defined for that service (in our case in the default cache location). If so, it will start the service in a disconnected manner.

Note, Arcgis server will make the decision about starting the service in a disconnected manner or not depending on the availability of the source data used to build up the Globedoc and cache (in the above example, it will start disconnected if source data for layers of GlobeDocX are not available on ServerY - these could be layers referencing an ArcSDE data, a mapserver or for that matter even a local data source that are not visible/available on ServerY). This enhancement, on the fly detection/inspection of the globe document to determine if there are caches available for it and start the service in a disconnected manner, is available with ArcGIS server 9.3.

Previously (at version 9.2) it would fail to start a service if you simply just copied the globe doc from one machine to another and the data sources were not available in the new setting. Now (at 9.3) it would evaluate to see if it can start it in a disconnected manner, just feeding off from the cache.

I hope this answers your question about migrating/moving 3D data caches from one machine to another.

PS If you intend to do this (move/copy the cache from one machine to another) you should not change the auto generated folder cache names (the layername+Unique Ids given for each cache). Also this feature is currently available only for globeservices.

re: Creating a Disconnected Globe Service

Carol Fackler — Thu, 04 Dec 2008 23:32:00 GMT

If I create a disconnected 3D cached service will I be able to use the Identify task on that Layer?

re: Creating a Disconnected Globe Service

Carol Fackler — Tue, 09 Dec 2008 18:46:21 GMT

I'm assuming the answer to my post above (Dec. 4th) will be no - it makes sense. One note of interest. The identify on our 2D caches were awful. Especially the point and line layers. They seemed to work randomly. Once we created 3D cashe the point and line layer identify was much more reliable. I guess I could go through the effort of disconnecting the cache to see if the identify would work but I'd be very surprised if it did.