ROK Technologies ESRI Developer Blog - ArcGIS Server FLEX

ArcGIS Server Identify Operations Slow?

Fri, 04 Jun 2010 12:24:00 -0400

Here is a quick tip for my fellow ArcGIS Server developers. While I have never been a big fan of using the Identify operation, there is no doubt that it can be quite useful at times. Its strange though, sometimes I have noticed that it was terribly slow (I have seen 8 sec+ response times on a simple 4 layer Identify). So, I'd do the normal thing, and remove some layers, and try again. It would usually end up being one specific layer that was causing the huge slowdown. I would just chalk it up to a bad layer and move on. Well, after running into this issue a few times, I couldn't really ignore it and blame it on a 'bad layer'. It turns out that these layers had something in common...The all had complex / detailed geometries. I'm not entirely sure why a complex geometry would effect an identify operation, but it does. So, my simple fix was to use ArcToolbox and perform a generalization operation against the layer. You GIS folks should be familiar with that type of thing. In short, it removes superfluous geometry in the shape. Instead of 1000 points along a curve, it can reduce it to say, 100. Visually, you can normally not tell the difference. But, to be on the safe side, I left the original layer alone, and just made a copy. Then, I use that copy in all all my identify operations instead of the original. Yes, it does create extra overhead and some additional logic in your app, but the run time processing saving is huge. My 4 sec response times have been cut to under 100 millisecs. Yeah, its that big of a difference. So, in my mind, totally worth the extra effort.

Hey You, Dummy, Read The Docs

Tue, 10 Nov 2009 12:36:00 -0400

I just wasted a good 2 hours trying to debug an issue with a AGS Flex application I am doing. I could not, for the life of me, figure out how I was able to deactivate a Draw Toolbar without explicitly calling drawToolbar.deactivate. It was driving me crazy. So, I decided to revert back to the Flex 1.2 API and sure enough, it was necessary to explicitly call drawToolbar.deactivate to stop drawing. However, I reason I had to revert back was because I think I may have found a bug with the ArcGISTiledMapServiceLayer tileServers. It was just coincidence that I tried 1.2. Turns out, the big dummy that I am, this is new (and very welcomed) behavior as of 1.3. I should have stopped, and read the docs and could have saved myself some time and frustration.

Coldfusion 9 Launched

Mon, 05 Oct 2009 14:50:00 -0400

Wow...Adobe just keeps wowing me with what they are doing with Coldfusion. Coldfusion 9 was released today. Check it out: Coldfusion 9 What a great time to be a Coldfusion developer...especially with the tight Flex integration...this make my ArcGIS Server development a breeze. I tend to do most of my searching via Coldfusion cfcs with front ends in Flex. Using serverside cfc's to construct straight REST calls to ArcGIS Server has also proved to be dead simple and powerful.

New Site Using Remote Cache Hosting Service - ArcGIS Server in The Cloud

Fri, 19 Jun 2009 12:58:00 -0400

Hey folks...Just wanted to share a site that is now using our remote cache hosting service to serve cached tiles. I previously showed several Javascript API sites uing this service, but this one is using Flex api for ArcGIS Server. This really frees up bandwidth to let the dynamic layers be served quickly. Those aerial images can be very bandwidth intensive, so hosting these remotely them makes a lot of sense when bandwidth is limited, or you have a high volume site. Here is is: Santa Rosa Planning and Zoning Viewer. The layer that is being served remotely is the 'Aerial Photos' layer. If you are a developer geek like me, check out the site with firebug enabled so that you can see the Aerial imagery being served remotely - meaning a different location that the ArcGIS server itself. Cool stuff.

Part 1 - Whats Is A Geoprocessing Task And Why Should I Care?

Wed, 17 Jun 2009 13:11:00 -0400

So, lets begin this discussion of Geoprocessing with ArcGIS Server that I promised. I guess the first question is what is geoprocessing and why should I even care? The big promise of ArcGIS Server has always been this: "Whatever you can do in ArcMap and ArcCatalog, you can now do with ArcGIS Server". I have often heard ESRI reps say 'You can even rebuild ArcMap if you want to'. Of course, no one would ever want to do such a thing, but wouldn't it be nice to have all that functionality available to you in a web based application? In the old days of ArcIMS and MapObjects IMS we were pretty limited in what types of geoprocessing we could do on the web. I can recall all sorts of crazy tricks with buffers that we used to write to really push ArcIMS to its limits. But, at the end of the day, it was still just a buffer, and there is only so far it will take you. How about a select by location, or a union, or a clip? Sorry folks, you were out of luck if you needed to do that on the web. But then, ArcGIS Server came around, and suddenly doing real geoprocessing became a reality. So, what is a geoprocessing task? In short, it is a set of server side tools called from a web based client. Users create a model using Model builder, and then publish that model to the web as a geoprocessing task. The output parameters of the model are then streamlined to your web application. Lets take for example a recent Flex application that I wrote (Check it out here). The purpose of this application is to help citizens locate their property and then return information about the zoning on that property. It sounds easy enough, right? I'll bet you are thinking, why not just do an Identify, and return results from the zoning layer? Ah, if it were only that easy. There can be many, multiple types of zoning found on a single parcel, so a simple identify by point will not work. We need to do a spatial analysis to get the property boundary that the map click point or address point resides in. Once we get the property boundary, we need to do a second spatial analysis to determine which zoning layers intersect that property boundary. So, how can we use a geoprocessing task to help solve this problem? I started by simply going into ArcMap and writing down the steps that it takes to get the results I need. Then, I used model builder to string together these tasks into a single workflow. Finally, I published this model to ArcGIS Server so I could access it from the web. The, the final product takes in a point, selects the containing parcel for the point, and returns the zoning types that are present in the parcel. Now, this is a pretty straightforward example. We could take this example much further. We could actually clip that zoning layer and determine precise percentages of each zoning type on that parcel. For parcels with multiple structures, we could determine the zoning district for each structure. List goes on. This scenario, while certainly not impossible to do by conventional means (thinking FIND, QUERY, and IDENTIFY tasks), becomes much, much easier to solve by using a geoprocessing task. It also combines all the steps into one task. Instead of writing a complex combination of code to perform these steps in javascript or actionscript (flex) on the client, I have created a new, reusable tool that does all of these steps for me, serverside. I hope this clears up what a geoprocessing task actually is and why you should care. Next up in the series, we'll tackle the technical aspects of actually creating and executing one from your web application.

ArcGIS Server Training - Charleston, SC

Wed, 03 Jun 2009 18:45:00 -0400

Everyone always asks for an excuse to visit Charleston... well here is your chance! ROK is hosting two ArcGIS Server training classes this August at College of Charleston's GIS Lab. Administering ArcGIS Server
2 Days (Monday, August 17th and Tuesday, August 18th) $850.00
Training will cover all the steps you need to get ArcGIS Server up and running in your organization. In addition, it will go into some of the more advanced functionality ArcGIS Server has to offer including building optimized map cache and publishing geoprocessing tools to the web. Here is a link to the outline for Administering ArcGIS Server:
http://www.roktech.net/training/Administering.pdf Developing Applications for ArcGIS Server
2 days (Wednesday, August 19th and Thursday, August 20th) $850.00
Training will give you the tools and knowledge to start developing fast light weight mapping applications that users are now expecting. ArcGIS Server 9.3 offers new APIs that allow developers to get their data on the web in a quick, stylish, and developer friendly interface. We will cover the JavaScript API, Flex API, and briefly discuss the WebADF. On day two of this training, we will set aside time for you to apply the skills you've learned to start creating or continue developing applications for your organization. ROK developers will be there to help you along the way. Here is the link to the outline for Developing Applications for ArcGIS Server:
http://www.roktech.net/training/DevelopingApplications.pdf For more information or to sign up for a class, please contact training@roktech.net

FLEX api for ArcGIS Server released

Fri, 01 Aug 2008 11:49:00 -0400

I was browsing the ESRI resource center this morning, and I saw an unfamiliar link. I was excited to see that the beta release of the Flex api for ArcGIS Server has been released. Us Adobe fanboys are going to have a good time with this...From ESRI: "Develop rich internet applications with ArcGIS services using the Flex framework. The API enables creating applications with intuitive, visually rich and responsive user interface. The ArcGIS API for Flex takes full advantage of the powerful mapping, geocoding, and geoprocessing capabilities of ArcGIS services." Check it out here

ArcGIS Server Flex API announced!

Tue, 18 Mar 2008 18:17:00 -0400

I had a little bird tell me about the upcoming Flex API for ArcGIS Server. I have been sitting on this one for a while and its been killing me not to share this. Well, looks like it has been officially announced at the ESRI Dev conference today, so I guess that means it is finally public knowledge. In my mind, AGS with Flex, and a Coldfusion backend is going to be one powerful force to reckon with. From what I have been told, its going to be similar in functionality to the recently released (beta) JS and REST api. It looks like its not slated for release until 9.4....but I have been promised (by my birdie friend) access to the early beta. I'll be sure to share what I can as info comes in...