ESRI vs. Google, Flex API Load Times Compared. Part 2

In an effort to be fair I decided to rerun the test I had done earlier, but this time using polygons. Part of the reasoning is that I feel that Google's Marker has a lot of crap that it has to draw, like the shadow and just the balloon shape alone would add time. The polygon in Google is just that a polygon and nothing extra. So I created 2000 different bounding boxes and let both ESRI and Google load them. As suspected Google's performance was much better but ESRI was still faster.

Google	ESRI
3.828 sec.	3.032 sec.
3.891 sec.	2.875 sec.
3.953 sec.	2.969 sec.

So the moral of the story is don't use Google's Marker if you want to go fast.

Try catch vs if statements

Many might already know this but I wanted to know for sure. Is it faster to use a try catch block or if statement. So I ran a simple test to find out. I created this function to run the try catch test;

private function testTryCatch() : void {
 var adder:Function = function a( x: int ) : int {
  return (x + 1);
 };

 var x:int = 0;
 var o:Object = { 0 : adder };

 for( var i:int = 0; i < 1000000; i++ ){
  var y:int = i % 2;
  try{ 
   x = o[y]( x );
  }
  catch( except:Object ){
   x = adder(x);
  }
 }
}

I then wrote an identical function except that it had an if( o[y] != null ) statement where the try was. Now what I found was that the if statement times did not change it took 0.57 seconds in all the tests. However, the try catch statements did not preform quite as well. As the number of exceptions are thrown the amount of time increases rapidly. Here is a table of times for the percentage of exceptions thrown over a million iterations.

0%	33%	50%	90%
0.5	4.219	6.031	10.422

I ran the function without the try catch/if statement and it took 0.422 seconds. If I subtract that from the times and then divide the number of exceptions thrown by the time you end up about 90,000 for each of the times. To put it another way, on my computer I can throw 90,000 exceptions per second.

So it seems like unless you are really do not like if statements it would be faster to use them.

ESRI vs. Google, Flex API Load Times Compared

I have been writing a set of several parsers (Shapefile, Shapefile DBF, KML, CSV, and Tab Delimited) that work for both ESRI and Google. The parsers format the data and pass it to an overlays factory class. The factory class has the map you are working with and also a set of default shape builder classes, that know how to build the appropriate shape for your map. This is the setup that I used to test the speed of loading points into both ESRI and Google maps.

First, I tested loading a kml with 1297 points. To get a baseline I commented out the call to the factory class and got an average parse time of 0.178. I have subtracted this time out of the times below.

Google's default Marker is slower, so in all fairness I set the marker options to { hasShadow: false , radius: 1 , icon : "none" }, this dramatically increased the load times for google.

Default Google	Modified Google	ESRI
3.697	1.462	0.416
3.651	1.447	0.384
3.665	1.462	0.385

As you can see the default ESRI point is considerably faster (8-9 times) than the default Google point. If you compare more the ESRI point to the modified Google point it is still faster (3-4 times).



I then ran the same tests for loading a shapefile with 1297 points. The baseline time for the shpfile parser was 0.11 (however the dbf took 4.01 seconds) and has been subtracted out of the times below.

Default Google	Modified Google	ESRI
3.947	1.703	0.562
3.838	1.577	0.468
3.796	1.656	0.453

The times are essentially the same as those in the last test. One interesting note though is that reading data from the dbf file makes using a shapefile prohibitevly slow as the amount of data grows.

So I would suggest parsing kml and putting it on a ESRI map for your best results.

Parsing KML with ActionScript XML e4x

I spent some time trying to figure out why I could not get the ActionScript XML object to properly parse a KML file and found out that the problem was in the namespace of the KML. KML sets its global namespace to whichever version of KML you are using. The problem is that when you try to access the tags using the e4x methods it does not work. So to fix the problem you need to then set the default namespace.

default xml namespace = new Namespace("http://www.opengis.net/kml/2.2");