Which ESRI Javascript API Version to Use – 3.x vs 4.x

by Ryan DavisonGISPosted on No Comments

Which ESRI Javascript API version should you use for your next mapping app? I wish it were as simple as just using the most up to date version. And maybe it will be for your situation. But there are a few considerations to address before pushing ahead.

Start With Your Goal

Always start with your goal. What do you want the app to look like and do? Probably, the biggest question you should ask yourself is whether you will be creating a 3D app or a standard 2D app?

As of this post, the 4.x API is at version 4.11. According to ESRI’s API Capability page, version 3.28 (the latest 3.x version) doesn’t support 3D rendering. Version 4.11 only has partial support for 2D. So, if you’re planning to create an app that supports 3D visualization in any way, you’ll need to use 4.11.

On the other hand, if you are only supporting 2D visualization you’ll want to use the latest API that supports all of the other functionality you might want to use. This is really important to consider if you’re thinking about migrating existing 3.x code to the 4.x world. You would hate to get deep into the conversion only to find out a critical component you rely on is not yet supported.

Check out ESRI’s functionality matrix to determine if 4.11 is implementing all the functionality you need right now. ESRI’s stated goal is to eventually have 4.11 eventually exceed the functionality of the 3.28 API. But until it does, you’ll want to proceed with at least a little bit of caution.

Consider Your Time

Another thing you will want to think about is the time you will spend getting up to speed on the syntax changes that version 4.11 brings. Right away, when creating a basic map with 4.11, you’ll notice that you now have to not only create a map but a map view (or map scene if it’s a 3D app) in order to get anything to render.

With the old 3.x API you would simply declare the map object and pass in a reference to the HTML element you want to use to render it in. As of 4.11, the Map object is now simply a container for the various layers you want to associate with the app you’re creating. There is now a new class called View that manages UI methods for your app like rendering the map within the HTML element and placing components (like widgets and images) on screen.

I like most of the new syntax changes that I’ve seen in 4.11 but I realize these slow down my development time as I get used to them.

Five Things I Love About the ESRI Javascript API

by Ryan DavisonProgrammingPosted on No Comments

Having worked with both the ArcGIS Silverlight and Javascript APIs I have to say Javascript has been much more fun. There is just something about working on the front end of a web map and being able to have it do so many amazing things. Here are my top five reasons I enjoy working with this API.

1. Your maps are device independent. Unlike the Flex and Silverlight APIs, Javascript and HTML5 can be viewed on almost any device. The obvious advantage here is that you can reach more people with your spatial data.  Of course having the ability to code for multiple devices means having to customize your code for different screen sizes which can turn into a lot of work. Check out this post from the Treehouse Blog for a great primer on responsive web design.

2. Plenty of code samples and live examples. Code samples are a great way to get your own map up and running quickly without having to figure everything out first. While the samples are not perfect they are a good way to discover map functionality that you might want to incorporate.

3. Support for a ton of layer and data formats. From GeoRSS and GeoJSON to KML and shapefile, this API pretty much covers it.

4. Well written API reference documentation. If you are going to use an API (any API) you want to be able to understand it so you can use it effectively. Good documentation is critical for this. The Esri JS API is (in my own humble opinion) extremely easy to read and understand. Each class has all the information you need to use it without having to decode any meanings. Furthermore, there are links from each class to samples that use it.

5.  Editing tools for online editing of SDE data. Let’s be honest, online editing through a web browser is not a great idea if you are trying to build accurate data. However, there is definitely a place for it. If you are trying to outline an area inhabited by a herd of elk or mark an area of weed infestation, browser editing is probably fine.  It is great just to be able to have this ability so more diverse mapping applications can be developed.

Wow, this list was a lot harder to write than 5 Things I Hate About the ESRI Javascript API. One reason is that there are other APIs out there that do a lot of what the ESRI API does (yes I am thinking about OpenLayers). Another reason is that as I write I think about things I would like ESRI to do better or differently. Oh well, you can’t have everything. Let me know what your thoughts are on the ESRI Javascript API – good or bad.

5 Things I Hate About the ArcGIS Javascript API

by Ryan DavisonProgrammingPosted on One Comment

Building a mapping application with ESRI’s Javascript API is a lot of fun. But it can also be a real pain. Here are five things that absolutely drive me crazy when writing an ArcGIS Javascript map.

1. It is based on Dojo. It’s probably just my lack of Javascript programming sophistication but I find Dojo a little hard to work with. Although the API documentation has improved in recent versions, I don’t find it very intuitive. If you are a beginner or new to Javascript, the getting started documents are just plain frustrating. Ben Farrell thinks there are seven stages of learning Dojo including anger and acceptance. I’m not sure if there are really only seven stages but I can attest to the anger and acceptance.

2. It uses multiple versions of Dojo. Here I go again with the Dojo thing. Half of the developer samples on the ArcGIS.com developer’s site seem to be written pre version 1.7 while the others are post 1.7 and rely on the AMD module format.  I understand that version transitions of supporting libraries can be difficult but this is ridiculous. Since the ArcGIS API updated to version 3.6, many of the developer samples have been updated to show the AMD require format. Unfortunately, the transition has been slow and there is still a lot of mixed version code and a lot of live samples are broken. If you are going to upgrade to a new version of your API, let’s have things ready to go.  

3. No built-in label engine for dynamic, on-screen annotation. It seems obvious to me that the users of a map would want to mark it up with text; especially in conjunction with a draw toolbar. Apparently it isn’t obvious to the ESRI developers. Instead we are left to work with with the labelPoints function which uses the geometry server to create an unseen point and then puts a text symbol on top of it.

4. The label engine problem above leads me to my next gripe. The LabelPoints function doesn’t allow line breaks. That means that if you want to label a polygon with something like, oh say, area and perimeter, you have to have it all on one line or call the labelPoints function twice and use an offset. How about we get the ability to at least use a newline character (\n) and be done with it.

5. No out-of-the-box support for a table of contents. There is a lot of debate about whether an ArcGIS-like table of contents is a good thing in a web map. No matter what side of the debate you fall on, the fact is that people are used to using them and users often want the ability to turn layers on and off. There are a few projects out there that attempt  to solve the problem but each has its own limitation and problems.  It is a little surprising that ESRI doesn’t have a solution for this one yet. Or, maybe it isn’t really that surprising.

I have plenty more gripes with the Javascript API than the ones listed above but I don’t want to get too depressing. Also, I actually enjoy developing with the API (most days) and there are some great things about it. If you want to add to my list put it in the comments.