#GIS from a .NET developer's perspective

ArcGIS Server .NET Code Gallery samples

Well what do you know... I'm also on youtube now. Together with several of our team members I'm demoing a custom renderer from the Code Gallery. Check it out!

Here are the links to the samples:

Other samples that you should check out (because I wrote them :-)):

Utility library: Simplifies ADF development for a number of common tasks. For example add a resource in one line of code, or create a redline tool using only a couple lines of code.

DHTML ScaleBar: Pure client-side scalebar. Instead of using the map services for drawing the scalebar, it uses a pure clientside approach (javascript), removing the need for server requests and scalebar re-rendering. It's also useful for resources that doesn't support rendering scalebars.

If you want know more I'll be working at the Server Showcase at the ESRI User Conference next week as well as demoing some more samples at the .NET SIG.

Spherical/Web Mercator: EPSG code 3785

I just received an update from the EPSG mailing list:

New to Version 6.15 are (among other things): Added spherical Mercator coordinate operation method and associated CRS as seen in popular web mapping and visualisation applications.

It looks like they FINALLY added the spherical Mercator / Web Mercator projection used in Virtual Earth and Google Maps.

This is a big surprise. EPSG’s earlier statement whether to include it was this:

"We have reviewed the coordinate reference system used by Microsoft, Google, etc. and believe that it is technically flawed. We will not devalue the EPSG dataset by including such inappropriate geodesy and cartography.

Guess they changed their mind, or did they just devalue their dataset? Then again, judging from the remarks EPSG put in there, their arrogance still shines through. There´s absolute nothing wrong with using a sphere instead of a flattened sphere. Sure it's not as accurate as for instance WGS84, but then again WGS84 is not accurate either - no ellipsoid is. But we know the exact differences between the two, and as always you will need to take these things into account so I don´t see the real issue. Viisually the distortion is far less than what you would notice, and when doing area, distance and bearing calculations you would first of all never use the mercator units without taking the projection distortion into account, and if you do your calculationg in long/lat it's more or less just as easy to use WGS84 as a base for your calculations (since no datum transform is really needed).

Anyway, finally we get an official code for "Web Mercator": EPSG:3785 

Here are the details of the entry:

Full WKT with authorities (untested!):
PROJCS["Popular Visualisation CRS / Mercator", GEOGCS["Popular Visualisation CRS", DATUM["Popular Visualisation Datum", SPHEROID["Popular Visualisation Sphere", 6378137, 0, AUTHORITY["EPSG",7059]], TOWGS84[0, 0, 0, 0, 0, 0, 0], AUTHORITY["EPSG",6055]], PRIMEM["Greenwich", 0, AUTHORITY["EPSG", "8901"]], UNIT["degree", 0.0174532925199433, AUTHORITY["EPSG", "9102"]], AXIS["E", EAST], AXIS["N", NORTH], AUTHORITY["EPSG",4055]], PROJECTION["Mercator"], PARAMETER["False_Easting", 0], PARAMETER["False_Northing", 0], PARAMETER["Central_Meridian", 0], PARAMETER["Latitude_of_origin", 0], UNIT["metre", 1, AUTHORITY["EPSG", "9001"]], AXIS["East", EAST], AXIS["North", NORTH], AUTHORITY["EPSG",3785]]

Projected CRS
COORD_REF_SYS_NAME: Popular Visualisation CRS / Mercator   
COORD_REF_SYS_KIND: projected   
COORD_SYS_CODE: 4499       
SOURCE_GEOGCRS_CODE: 4055 (see below)
CRS_SCOPE: Certain Web mapping and visualisation applications.   
REMARKS: Uses spherical development. Relative to an ellipsoidal development errors of up to 800 metres in position and 0.7% in scale may arise. Some applications call this WGS 84. It is not a recognised geodetic system: see WGS 84 / World Mercator (CRS code 3395)   
REVISION_DATE: 3/14/2008

Geographic CRS:
COORD_REF_SYS_NAME: Popular Visualisation CRS
COORD_REF_SYS_KIND: geographic 2D
DATUM_CODE: 6055 (see below)
CRS_SCOPE: Certain Web mapping and visualisation applications.
REMARKS: Some applications erroneously call this WGS 84. It uses a sphere with a radius having the same value as the semi-major axis of the WGS 84 ellipsoid. There is no geodetic recognition of this system.
REVISION_DATE: 3/13/2008

Code: 6055       
Datum Name: Popular Visualisation
Datum Type: geodetic
Origin Description: Not specified in the classical sense of defining a geodetic datum.
Datum Epoch:
Ellipsoid Code: 7059 (see below)
Prime Meridian Code: 8901
Area Code: 1262
Datum Scope    : Used by certain popular Web mapping and visualisation applications.
Remarks: Not recognised by geodetic authorities.
Information Source: Microsoft.
Data Source: OGP   
Revision Date: 13-Mar-08
Change ID:
Deprecated: No

Code: 7059
Ellipsoid Name: Popular Visualisation Sphere   
Semi-major axis (a): 6378137   
Axes units code: 9001       
Inverse flattening (1/f):
Semi-minor axis (b): 6378137   
Ellipsoid?: No   
Remarks: Sphere with radius equal to the semi-major axis of the GRS80 and WGS 84 ellipsoids. Used only for Web approximate mapping and visualisation. Not recognised by geodetic authorities.   
Information Source: Microsoft.
Data Source: OGP
Revision Date: 14-Mar-08
Change ID:   
Deprecated?: No

Vote for a future Earth Day

So it's Earth Day today, and there are all sorts of blog posts out there on saving energy like saving a few watts with a new and better lightbulb, or pissing a lot of people of by driving a little slower on the highways. All these honorable initiatives are great and admirable, but I don't think they have much effect, because there are just way too few does these things (maybe we are just too stupid and/or lazy), and what we do is far from enough. What we really need is the politicians to set tough goals and invest heavy in technologies that really can make a change.

So what can you really do? Well you can vote for the politicians you think will do the most to make that happen. Currently the American Presidential election is still on-going, so judge from yourself. All 3 candidates have a page dedicated to environmental issues, so I pulled some bullets from their campain websites (but go read the full thing on the links before you decide), so you can judge from yourself. Of course there are many other important issues to look at, but given the current state of the world and that the United States wastes more energy than anyone else, I personally think it's of the highest importance. We had a great run the last century, but I'm afraid we have to start paying the bills...

Hillary Clinton -

  • Reduce electricity consumption 20 percent from projected levels by 2020.
  • A $50 billion Strategic Energy Fund, paid for in part by oil companies, to fund investments in alternative energy.
  • Doubling of federal investment in basic energy research.
  • Aggressive action to transition our economy toward renewable energy sources, with renewables generating 25 percent of electricity by 2025 and with 60 billion gallons of home-grown biofuels available for cars and trucks by 2030.
  • 10 "Smart Grid City" partnerships to prove the advanced capabilities of smart grid and other advanced demand-reduction technologies, as well as new investment in plug-in hybrid vehicle technologies.
  • An increase in fuel efficiency standards to 55 miles per gallon by 2030, and $20 billion of "Green Vehicle Bonds" to help U.S. automakers retool their plants to meet the standards.
  • A plan to catalyze a thriving green building industry by investing in green collar jobs and helping to modernize and retrofit 20 million low-income homes to make them more energy efficient.
  • A new "Connie Mae" program to make it easier for low and middle-income Americans to buy green homes and invest in green home improvements.
  • A requirement that all federal buildings designed after January 20, 2009 will be zero emissions buildings.

Barack Obama -

  • Reduce Carbon Emissions 80 Percent below 1990 levels by 2050
  • Invest $150 billion in a Clean Energy Future, double energy research, 25% renewable energy by 2025 and develop clean coal energy.
  • Support Next Generation Biofuels Two billion gallons of cellulosic ethanol by 2013, require fuel suppliers to reduce the carbon their fuel emits by ten percent by 2020, 36 billion gallons of renewable fuels to be included in the fuel supply by 2022 and will increase that to at least 60 billion gallons of advanced biofuels like cellulosic ethanol by 2030-
  • Set America on Path to Oil Independence, by reducing oil consumption by at least 35 percent, or 10 million barrels per day, by 2030.
  • Improve Energy Efficiency 50 Percent by 2030. Make all new buildings carbon neutral, or produce zero emissions, by 2030. He'll also establish a national goal of improving new building efficiency by 50 percent and existing building efficiency by 25 percent over the next decade to help us meet the 2030 goal.
  • Restore U.S. Leadership on Climate Change

Johm McCain -

No bullets to pull from his website.  Generally very vague plans (especially compared to many of his other important issues, like the right to bear arms):
 “Along with his commitment to clean air and water, and to conserving open space, he has been a leader on the issue of global warming with the courage to call the nation to action on an issue we can no longer afford to ignore. [...] By addressing this problem responsibly, John McCain believes we can meet our obligation to be proper caretakers of creation, in a manner of which we can be proud - by protecting our country, strengthening our economy, and addressing the challenges of our time, rather than leaving a much worse problem for our children”.

So what am I going to vote you may ask? Well unfortunately I'm caught in the legal void between two countries and therefore not allowed to perform my democratic responsibility, but hopefully I made one or two people change their mind for the better with this blogpost.

And sorry for the off-topic post.

IE8 will be the only browser not to support opacity

I recently blogged about that IE8 beta1 currently doesn't have any support for the CSS3 opacity property or the alpha filters that is used in IE5.5/IE6/IE7. Microsoft had noted in one of their whitepapers that they would plan on adding some CSS3 support based on customer feedback. The lack of opacity is one of the most requested features in their bug tracking system, so natually I figured that they were going to add opacity to a future beta.

However, this week the IE team wrote that they are NOT going to include this in IE8 but will consider it for a future version.

This would make IE8 the only browser to not support any form of opacity, and "break" A LOT of exisiting websites, tools etc. that rely on this (including several of Microsoft's own websites and API's). I'm flabbergasted.

If you as me think this is wrong, go and sign up for the IE8 beta program and vote and comment on this issue.

Click here to sign up for the IE8 beta program. Afterwards you should be able to see, vote and comment on the opacity bug entry:

Update: Beta 2 just released and Scott Dickens had promised the filters would be back in IE8 for beta2. Doesn't seem like it though! (and why the filters anyway??? why not do it like everyone else and use opacity)

Internet Explorer 8 whitepapers

I was looking into some of the IE8 issues we are having, and found this great site full of Microsoft white papers on IE8.

There are a lot of nice tips and tricks, both about what to be aware of that might have broken your website in IE8, but also tips and tricks on how to optimize your code to utilize some of the new features of IE8.

Opacity NOT supported
IE8 beta 1 does not support adding semi-transparency to any object, neither by using the proprietary filter object or using the CSS3 opacity style property. However, I found this interesting comment in the CSS2.1 compliance paper:

While one of Internet Explorer 8 Beta 1 for Developers' main goals is CSS 2.1 compliance, it is also forward looking towards CSS3. […] Internet Explorer 8 hopes to implement some of the most requested CSS3 features by web developers and designers'.

'opacity' is part of CSS3, and there is a feature request for it on Microsoft connect, and has already gotten a fair amount of votes. Although everyone cannot submit bugs, everyone can vote, so go vote for this missing feature here!

See update here 

VML NOT supported
Microsoft heavily Improved Namespace Support, but I think they didn't think about where that leaves VML. Basically there is no VML support (or SVG for that matter). For GIS apps this is a must. I would prefer seeing an SVG engine instead (saves us having to make two graphics APIs), but VML will do. You can vote for it here.

Here are a couple of things I found interesting in the white papers that I post here for my own reference, but you might find them useful too:

Outline (CSS2.1 compliance paper)
Outline allows you to highlight an element without affecting its size or the layout of the rest of the web page. You can think of outline as an enhanced border that is allowed to overlap other elements without changing the layout of a page. An outline is drawn right outside the border edge, and unlike the border attribute, it won't cause the size of objects to change and move around.

Syntax is the same as with border. Example:

         <div onmouseover="'5px solid yellow';" onmouseout="'';">


         myElement.outline = '5px solid red';

An interesting property of ‘outline' is the ability to set the color to invert. This causes the outline to take on the color which is the inversion of the pixels it is overlapping. This guarantees that the outline is always visible, no matter what type of element (even an image) it overlaps. Here is an example of an element with color set to invert: div { outline: thick solid invert }

document.getElementById (DOM Core Improvements)
In Internet Explorer 7, this method searches for and returns the first element that has an ID attribute or name attribute that case-insensitively matches the parameter string.

In Internet Explorer 8, this method finds only elements that have ID attributes that match the given parameter value in a case-sensitive manner. (ID attributes should be interpreted as case-sensitive as per the HTML 4.01 specification).

If you tested with FireFox and do the same in both browsers, this might not be an issue for you, since FireFox is case-sensitive and doesn't use the name tag.

Selecting elements by class (Selectors API)
You can now look up elements very fast by using their class name. So if you know you are doing a lot of searching for specific elements, give them a unique class name and search for them using:

var oneElement = document.querySelector('myClassName');
var elementCollection = document.querySelectorAll('myClassName');

Search for multiple classes at once:

var elementCollection = document.querySelectorAll('myClassName1, myClassName2');

You can limit the scope of the search by using the querySelector/querySelectorAll methods on the individual elements.

Neat! This is one API I hope the other browser vendors will copy!

Switching to IE7 mode (Selectors API)
You probably already know this one, but add this metatag to the page, and everything that works with IE7, should work with IE8 (but this is cheating ;-)

<meta http-equiv="X-UA-Compatible" content="IE=7">

Looping through elements within a node (Platform Performance Improvements)
Modify any chain of lookups to cache the intermediate values, so that the final lookup is the only one made repeatedly (this one is not really new to IE8, but IE8 introduces some internal caching of nodes to improve look-up).


function badLoop(div1) {
    for(var i=0; i < div1.parentNode.childNodes.length; i++) {
        var node = div1.parentNode.childNodes[i];
        // Do something with node.


function betterLoop(div1) { // Cache length and array to prevent multiple lookups.
    var childLength = div1.parentNode.childNodes.length;
    var childNodes = div1.parentNode.childNodes;
    for(var i=0; i < childLength; i++) {
        var node = childNodes[i];
        // Do something with node.

Use the nextSibling method to traverse the children of an element. For example, improve betterLoop with this (nextSibling is a new property, and this is very similar to the best practice for traversing XML nodes in .NET):

function bestLoop(div1) {
    for(var node = div1.parentNode.childNodes[0]; node != null; node = node.nextSibling) {
        // Do something with node.

String concatenation (Platform Performance Improvements)
We were taught to use Arrays for joining strings efficiently. Now we don't have to worry about that anymore:


var smallStrings = new Array(); // Fill array with smaller strings 
var largerString = smallStrings.join('');


var smallString1 = "string1";
var smallString2 = "string2";
// String concatenation using the "+" operator
var largerString = string1 + string2;

Working with arrays (Platform Performance Improvements)
Array now comes with built-in Push and Pop methods.

var standardArray = new Array();
standardArray.push("Test String");

More connections for broad-band users (Better AJAX Development)
So here's actually one where Microsoft breaks with the standards:

 "An increasing number of users have broadband connections, so client-side bandwidth is not always a gating factor for performance. Typically, the time required to set up a connection and send a request dominates the time spent retrieving individual objects. The limit of two connections was set by the HTTP 1.1 specification (RFC 2068). By increasing the number of concurrent connections, Internet Explorer 8 Beta 1 for Developers allows Web sites to amortize that cost and churn through the list of pending objects more quickly, leading to an increase in user-perceived download time. Internet Explorer 8 Beta 1 for Developers consequently includes logic that detects whether the connection is narrow-band or broadband and increases the number of connections per host to six if it's a high speed connection. This maximum number of connections applies to any connection to a Web server, not just to downloads."

Notes from Mix08

Virtual Earth announced during their session that they will release a Silverlight Control for embedding maps in your silverlight app. It will be interesting to see if the silverlight adds any benefit over the HTML/JS control.

Deep Zoom: This is an unmanaged part of SilverLight and not very customizable. The tilingscheme is hardcoded. You cannot create images larger than 4x4billion pixels. That's still enough for having a sub-millimeter precision image of the entire earth, so I think that should be sufficient!

The Steve Ballmer Keynote was very entertaining. It was more of a live interview than a keynote. Rumour has it that the questions he got really upset him, but he hides it very well. WATCH IT!

Other sessions worth watching:
Developing ASP.NET applications using the Model View Controller Pattern
Scott Hanselmans' presentation on WPF user controls was the best session that I attended, and also very entertaining. I talked to him today and he admitted to be nervous which was partly why he kept shooting off jokes. It turned out to be be the best presentation, so it worked out :-)

Developing Cutting Edge Web Applications With Internet Explorer 8
Lots of good tips on changes from IE7 to IE8. Espcially the part about the stuff they fixed that will break existing apps is a must read. Also a bit about new features, XDomainRequest objects, new accessibility features etc.

Creating Rich, Dynamic interfaces with Silverlight 2


Checking browser version in IE8

IE8 comes with an "Emulate IE7" button, which will revert the page back to run as IE7. This is great for developers who can quickly test their apps in both versions (I just wish we could have an IE6 button too!).

Furthermore you can place a tag in the page that will force IE8 to render the page as IE7 would have. However this poses a problem. Lets say you make some javascript that takes IE8 into account with version checking, but the page has this IE7-compatibility tag embedded. The JavaScript browser version check would still report v8. Instead for IE you should use 'document.documentMode' to get the version number. That means that if you set your browser to run as IE7, this would return version 7 (even though it really is 8), and if you set in quirks mode, you will be getting v5. It would be safer to adjust your javascript using this property.

I ran some few tests on the fresh IE8 beta1. It still looks pretty much like IE7. This blog runs with only one minor problem. I have a gallery page that relies on AjaxControlToolkit, and this really broke on IE8. Hopefully the AjaxControlToolkit team will quickly get all those issues fixed.

There are 4 IE8 specific sessions at the Mix conference. Keep an eye on them at the Mix Website when they come online (about 24 hours after the session):

  • BCT08 - Welcome to Internet Explorer 8  Wed March 5 at 1:30 PM to 2:45 PM
  • CT07 - Cross-Browser Layout with Internet Explorer 8  Wed March 5 at 3:00 PM to 4:15 PM
  • T21 - Integrating Your Site With Internet Explorer 8  Thursday March 6 at 8:30 AM to 9:45 AM
  • T04 - Developing Cutting Edge Web Applications With Internet Explorer 8  Friday March 7 at 8:30 AM to 9:45 AM
  • Here's a picture from the first session, showing the Acid2 test:

    IE8beta1 and Silverlight 2.0 beta 1 available

    Reporting live from the Mix08 conference in Vegas :-)

    Internet Explorer 8 beta1 and Silverlight 2.0 beta1 will be available from today !

    IE8 comes with a much improved Developer tool with full debugger and style tracing, CSS2.1 and HTML5 support. You better get testing in IE8, because your existing website might be broken in IE8 (since it now finally follows the standards).

    Silverlight will also be available for Mobile, and is supported by Nokia who will add it to their S40 and S60 series. You can already see a mobile silverlight app here: This app was developed in less than 3 weeks and works cross-platform, cross-browser, cross-mobile, cross...


    My computer is too smart just have a weird way of saying things. For instance, today it tried telling me that I shouldn't be working on a Sunday.

    When I booted up XP, this message kept popping up, and my Windows folder was empty:

    The file or directory C:\Windows is corrupt and unreadable. Please run the Chkdsk utility. 

    The funny thing is that apart from this message was constantly popping up, everything seemed to run just fine.

    I took a backup, rebooted, CHKDSK started up automatically, fixed a few links, and everything seems to run fine again. PHEW! (but I'd better get that harddrive checked)

    UPDATE: Two weeks later the harddisk crashed completely. Thank God for backups !

    New SQL Server Spatial blog

    It looks like Ed Katibah (Spatial Program Manager of SQL Server) finally started blogging.

    His first blogpost covers some interesting changes in the latest February CTP.

    There are some new methods added to the list:

    • Geometry::Filter
    • Geography::Filter
    • Geography::EnvelopeCenter
    • Geography::EnvelopeAngle
    • Geography::STDistance is no longer limited to having one of the inputs of type Point.
    • Geography::Reduce

    Unfortunately I can't try these new features today, because a bug prevents you from using SQL Server 2008 on a Leap Day and the doc on MSDN doesn't cover these new methods yet, so there's not telling how these methods really work.

    Ed's and Isaac Kunens blogs are a must-read if you plan on doing some serious SQL Server Spatial work.