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iPhone Maps Offline?

RobDunfey

Just wondering if it will be possible to have 'Offline' iPhone maps using the new SDK. The workflow is a user connects to an ArcGIS Service prior to going out in the field, browses to the area they plan to visit, and then the contents of the service is downloaded and stored locally on the iPhone?

Rob

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MikeQuetel

Agree with this request... having cached tiles available, to get a user through a period of limited or no internet connectivity would be very, very valuable.

DiveshGoyal

The SDK does not currently support working in offline mode. For all practical purposes, network connectivity is required to work with GIS services. The map control does try to make efficient use of the network, but it relies on having access to the GIS services at any given point.

However, this is very valuable feedback and we will take it into consideration going forward.

Are there any special circumstances under which your application may need to work in a disconnected environment, or is just due to unavailable/choppy network connection?

_
Divesh

MelvinTan

Having cached tiles would indeed be valuable. For example, a Parks application which uses the map and overlays information such as foot paths, restrooms, attractions etc. In this case having cache would mean less reliance on the data network, resulting in faster loading times too.

That would be an added benefit for iPod Touch users as well, who can first browse the area they intend to visit while connected, so that they can still view the map while at the park, where there is no WIFI as well.

GeorgeVernardos

The SDK does not currently support working in offline mode. For all practical purposes, network connectivity is required to work with GIS services. The map control does try to make efficient use of the network, but it relies on having access to the GIS services at any given point.

However, this is very valuable feedback and we will take it into consideration going forward.

Are there any special circumstances under which your application may need to work in a disconnected environment, or is just due to unavailable/choppy network connection?

_
Divesh

Accoring to the Reference we can create our own customTileLayerClass inheriting from AGSTiledLayer, but we do not know how to implement these two methods.

- (UIImage *) tileForLevel: (NSInteger)level row:(NSInteger)row column:(NSInteger) column
- (NSOperation *) tileForLevelAsync: (NSInteger)* level row: (NSInteger)* row column: (NSInteger)* column

Can these delegates be used to retrieve images from application resources instead of Arcgis server?

MikeQuetel

The SDK does not currently support working in offline mode. For all practical purposes, network connectivity is required to work with GIS services. The map control does try to make efficient use of the network, but it relies on having access to the GIS services at any given point.

However, this is very valuable feedback and we will take it into consideration going forward.

Are there any special circumstances under which your application may need to work in a disconnected environment, or is just due to unavailable/choppy network connection?

_
Divesh

Thanks for the feedback, Divesh... can't encourage ESRI enough to consider offline and disconnected capabilities in this SDK.

The general scenario I have in mind is:

1) Wireless networks are sometimes unavailable, unreliable or get congested. The ability to cache base map data allows a user to continue working (doing data collection, for example) if they have the context of these maps. My application keeps track of network availability and caches the user input locally then uploads it to the server when connectivity returns. The missing piece would be base maps. The reason for the lack of connectivity could include being in a rural area, it could be post disaster and the cell network is down, it could be because the user is in a building or area of wireless interference.

I also would be very interested in the answer to gvernar's question: Could AGSTiledLayer be subclassed such that my class could take on the responsibility of serving locally persisted basemaps?

DiveshGoyal

It is concievable that you can write your own custom layer that uses a local cache. You would be responsible for getting the cache on the device, and then implementing the logic to retrieve a particular tile taking into consideration the cache's tiling scheme. Doable, but can be tricky

We haven't thoroughly exercised the workflow of creating custom tiled layers at this time. But you can try subclassing the AGSTiledLayer if you're feeling adventurous, . Here's how it would work (in theory) :

Sub-classes must provide implementation for the spatialReference , fullEnvelope , initialEnvelope, and units properties declared by AGSLayer, and the tileInfo property declared by AGSTiledLayer. They must also provide implementation for the tileForLevel:row:column: and tileForLevelAsync:row:column: methods and notify the tileDelegate when appropriate. It is also the responsibility of sub-classes to update the loaded property and notify the delegate when appropriate.

GeorgeVernardos

It is concievable that you can write your own custom layer that uses a local cache. You would be responsible for getting the cache on the device, and then implementing the logic to retrieve a particular tile taking into consideration the cache's tiling scheme. Doable, but can be tricky

We haven't thoroughly exercised the workflow of creating custom tiled layers at this time. But you can try subclassing the AGSTiledLayer if you're feeling adventurous, . Here's how it would work (in theory) :

Sub-classes must provide implementation for the spatialReference , fullEnvelope , initialEnvelope, and units properties declared by AGSLayer, and the tileInfo property declared by AGSTiledLayer. They must also provide implementation for the tileForLevel:row:column: and tileForLevelAsync:row:column: methods and notify the tileDelegate when appropriate. It is also the responsibility of sub-classes to update the loaded property and notify the delegate when appropriate.

As i understand the AGSTiledMapServiceLayer gets all of the following info

spatialReference
fullEnvelope
initialEnvelope
units
tileInfo

from the mapserver using Json - > http://mydomain.com/ArcGIS/rest/services/myMap/MapServer?f=json&pretty=true

??? So if this is true than we can store a text file in the application resources, that containins the JSON. Loading the json from this file and populating all the initial fields should be easy .

It would be very helpful if we can take a look at the implementation of AGSTiledMapServiceLayer class. ( .h and .m files ). Is this possible ?

FrédéricHUMBERT-DROZ

It is concievable that you can write your own custom layer that uses a local cache. You would be responsible for getting the cache on the device, and then implementing the logic to retrieve a particular tile taking into consideration the cache's tiling scheme. Doable, but can be tricky

We haven't thoroughly exercised the workflow of creating custom tiled layers at this time. But you can try subclassing the AGSTiledLayer if you're feeling adventurous, . Here's how it would work (in theory) :

Sub-classes must provide implementation for the spatialReference , fullEnvelope , initialEnvelope, and units properties declared by AGSLayer, and the tileInfo property declared by AGSTiledLayer. They must also provide implementation for the tileForLevel:row:column: and tileForLevelAsync:row:column: methods and notify the tileDelegate when appropriate. It is also the responsibility of sub-classes to update the loaded property and notify the delegate when appropriate.

Hi,

Thank you for this information. I've been trying to subclass the AGSTiledLayer, but after adding it to the mapview, the tileForLevel:row:column: and tileForLevelAsync:row:column: methods are never called.

Do you know if there is anything special to do in the init: method or anywhere else ? It seems I've implemented all the properties needed.

Best regards,

JeffPapirtis

have you been able to cache? I know my skills are not at this point, but this is a must have feature for my companies business applicaiton.
We have field personel that must be able to cache maps for use out in the field where cell coverage is spotty.

TomShindler

It may be beyond any technological intent of this app and sdk, but since the ESRI environment, data, and tools are where all of my expertise lay, it's the best bet:

I produce a series of paper topo maps for wilderness trail use, and customers have inquired about the possibility of buying them as iphone/pod apps.

I would like the ability to create an app that would run in ArcGIS for iOS that would contain an embedded map, and require no connectivity, ever, since the area in which it would be used would have no WiFi or cell phone access. The only connectivity of interest would be the GPS on the iphone, since those signals ARE available in the wilderness. By embedding the map in the app, I can charge appropriately for it, just like an itunes song.

Is this vision totally out of the envelope of this app?

AlexCrothers

I use Offmaps, great app, if this functionality can be replicated by ESRI then we are in business, the problem is more to do with copyright access to the data hence offmaps use of OpenStreetMap data which is free. cc.

http://www.offmaps.com/

"OffMaps lets you take your maps offline. It is the ideal companion for any iPhone and iPod Touch user, who wants to access maps when travelling abroad (and avoid data roaming charges) and who wants to have fast access to maps at all times"

Cheers
Alex.

DavidCoulter

The discussion here answers a question I posted yesterday. The reality is that many people use mobile GIS in remote areas with no connectivity (geologists, foresters, biologists, etc.). This may be due to remoteness or overseas projects (most research budgets or companies will not cover the roaming costs; and access to map servers is blocked in some countries).

The standard right now is an HP Ipaq running ArcPad. It has been noted in reviews of the iPad 3GS that mapping is the future "killer app" for the iPad. The screen size, brightness, weight, native GPS and COST are all in the right range (think $6,000+ and several lbs for a Toughbook). Ideally we need the ability to download proprietary base imagery and shapefiles onto an iPad from a PC, edit the shapefile in the field, and upload the shapefile back to a PC. You may not have connectivity at your hotel or basecamp so direct PC connectivity (cable or Bluetooth) is needed rather than a server-client model.

LeslieBright

FWIW: I'm a geologist, and am often in areas w/o any available coverage; I've GeoXT's and Juno's and Recons w/ a ProXH; while I'm used to ArcPAD 7 and 8, I more often am using TerraSync.

I've just gotten an iPhone, and would love to be able to store map data on the phone for use when out of coverage. It makes a lot of sense, for mapping purposes.

Another vote for being able to cache data for use.

JoelRobinson1

I am a geologist and I will second any and all requests for the ability to locally store maps. I have tried to use ArcPad in the past in combination with HP IPac and a more ruggedized GPS running Windows CE and was not completely satisfied with the experience. The biggest drawback has always been screen size- with the iPad, the screen is approaching something usable. But, most of the areas where I will be working will have limited (if I am really lucky) to no connectivity. The ability to locally store maps during times of connectivity is key.

KyleNegri

Offline access to maps would be amazingly useful. I'm a geologist in Alaska that works for an exploration company and consolidating our field gear (GPS, Palm PC, digital camera, compass, etc) into one device that doesn't crash six times a day would be huge. Please please please find a way to make offline map access happen and release me from incompatible uni-tasker hell.

GaryJohnson

Hi,

Thank you for this information. I've been trying to subclass the AGSTiledLayer, but after adding it to the mapview, the tileForLevel:row:column: and tileForLevelAsync:row:column: methods are never called.

Do you know if there is anything special to do in the init: method or anywhere else ? It seems I've implemented all the properties needed.

Best regards,

HI ... Just wondering if you ever manage to create your own custom tiled layer as per this thread? If so are you able to post the code. Thanks!

FrédéricHUMBERT-DROZ

HI ... Just wondering if you ever manage to create your own custom tiled layer as per this thread? If so are you able to post the code. Thanks!

Hi,

Well no, I tried not a long time. I managed to call a AGSOperation, but then I don't know what to do, the operation never stops and don't know what delegate to call... So I gave up.

BrianKowalski

The SDK does not currently support working in offline mode. For all practical purposes, network connectivity is required to work with GIS services. The map control does try to make efficient use of the network, but it relies on having access to the GIS services at any given point.

However, this is very valuable feedback and we will take it into consideration going forward.

Are there any special circumstances under which your application may need to work in a disconnected environment, or is just due to unavailable/choppy network connection?

_
Divesh

Divesh,

We at the US Coast Guard often have users operating in waters far from available netoworks. For us, operating in a disconnected environment is a must. I hope ESRI is working on adding this functionality to all of it's mobile SDK's

Thanks,

RickJones

Take a look at the OfflineTiledLayer sample and the OnlineOfflineFeatureLayer sample.

BrianKowalski

Take a look at the OfflineTiledLayer sample and the OnlineOfflineFeatureLayer sample.

Thanks much Rick!

NimeshJarecha

Today, the new version (v2.1) of the API is released. Please use new AGSLocalTiledLayer. See What's new in version 2.1.

Regards,
Nimesh

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