Last Sunday I had the pleasure to participate in making an aerial map, a very detailed overhead image of Dolores Park taken from 200’ to 400’. The fine folks at Public Laboratories have published the result. A couple of direct links: a full page slippy map and aerial video. I also got a nice single shot of the new Dolores Park playground (full size).

This kind of mapping comes from Public Laboratory, a cool non-profit helping ordinary people make their own aerial maps. You don’t need a satellite or fancy cameras on a plane to make a “satellite map”. All you need is a kite or balloon, a cheap point and shoot camera, and a little software.

I particularly like how low tech the setup is. The lift comes from something as simple as a mylar balloon filled with helium (we used a car dealership ad balloon). No fancy cradle, just some rubber bands holding the camera to a plastic soda bottle with the soda cap as the clamp. And no special camera, just an ordinary consumer camera set to continuous drive with another rubber band holding down the button. Launch, fly for awhile, pick the best photos, then stitch them together into a map. (That last part takes some effort; you can do it by hand in Photoshop or use the MapKnitter web app).

The Dolores Park shoot was mostly for fun, a nice way to be outside on a sunny day and excite a bunch of kids. But Public Laboratories participates in more serious projects too, like documenting the Deepwater Horizon oil spill. A key thing about this kind of mapping is anyone can do it relatively cheaply and quickly. You can also fly other sensors, they’re doing a lot of work in environment monitoring,

Many thanks to Stewart Long and Bobby Sudekum for letting me tag along on the fun photo shoot.

Photoshop CS2 is the most expensive piece of software I own. I wanted to migrate my license to Vista and it wasn't as simple as I'd like. The main challenge is CS2 is an old version and Adobe claims it does not work on Vista. Here's how to make it work anyway. I'm assuming you have a legal copy: do not steal software.

1. Get install media. If you have CDs you're in business. Otherwise write to Adobe support and tell them you need to download a CS2 installer. Do not mention Vista; they'll tell you that you have to spend $200 on an upgrade to CS3. They sent me an FTP link with a password for Photoshop_CS2_9.0_WIN_ACT.zip.
2. Unzip the install media. Don't just double click the installer and run from the virtual folder; the Adobe installer will break with the meaningless errors .\AutoPlay\main.ini MAIN_FILE_VERSION PRODUCT_REGISTRY_PARENT PRODUCT_REGISTRY_KEY. Extract files and run from the new folder.
3. Run the installer. Grant it permissions via the usual Vista UAC popup.
4. Run Photoshop. Activate it.
5. Allow Photoshop to update itself. Grant the Updater permissions via UAC.
6. Reboot. (Screw you, Adobe).
7. On reboot, you'll get an error that Vista blocked programs at startup because they asked for permissions. Run the Vista tool recommended in the error box and disable all of Adobe's startup tasks (gamma control, updater). The error will go away and your computer will boot faster, too.
8. Enjoy Photoshop!

I'm sure there's some lurking Photoshop / Vista compatibility problems. But I was able to edit a raw photo from my camera, that's all I really care about. I didn't test color management and printing, I could see potential problems there.

I finally figured out why the colours in all my photos on Flickr look wrong: Firefox is stupid and broken and doesn't honor embedded ICC color profiles. I've been doing all my photo editing in Adobe RGB and saving Adobe RGB JPGs with ICC profiles attached. Firefox ignores the profile, interprets the images as if they're sRGB and the colours end up all washed out.

One solution for this is to tell Photoshop to just do all the work in sRGB, the default that color-stupid apps like Firefox assumes. But I'm stubborn and want to use Adobe RGB when editing on the off-chance I want to print something. The solution is to convert to sRGB right before saving the JPG, via "Edit / Convert to Profile". In theory the Photoshop "Save for Web" option will take care of this for you, but in didn't seem to work for me and save for web does other things wrong anyway.

Awhile back I bought a ColorVision Spyder to calibrate my monitors. It works great, makes a huge difference. Now that I understand better how profiles work (or don't work, in the case of Firefox) I think I can get consistent colour all the way to the printer.

Flickr started as a side project from a high concept online game that was really an excuse to socialize and collect things. The photo thing took and the Flickr guys were smart enough to cultivate a success when they found it, but games still pop up inside Flickr from time to time. Users are the ones inventing Flickr games now. I just noticed a new one, a variety of "your photo is good" badges people put in the comments of photos like this one. Flickr Gold lets you give out gold medals after you get one, Flickr Poker and High Five let you hand out several awards a day and accrue kudos to photos with lots of awards. Sort of a carebear version of an old Flickr game, deleteme.

These games seem a bit silly, but I think people really like this kind of tokenization. It's not enough to say "this photo is good", the ritual of collection and the structure of game rules makes it seem more significant for people.

On Flickr there's a useful thread describing a quick trick to make colours pop. You take your photo, convert to Lab color mode, then compress the a and b colour channels. This has the effect of making colours generally brighter at the cost of destroying some detail in intensely coloured parts of an image.

Not always a good idea, but it can make certain pictures look better. I've done it to about 5% of my photos I put on Flickr. To make life easier I've created a Lab color pop action set for you to download. First you should try the method manually once to understand what it's doing.

Thanks to Flickr it's finally easy to use geotagged photos. Alas, the workflow is still very clumsy for using a GPS to geotag. Here's what I came up with for Windows.

1. Get a GPS. Six months ago the Garmin Forerunner 301 was the smallest thing I could find with a USB interface. The newer Forerunner 205 looks good, as does this upcoming Sony thing.
2. Walk around with the GPS tracking your location and take some photos. Make sure the clocks on the GPS and the camera are synchronized.
3. Dump the GPS track log to a .gpx file. Garmin drivers are here. I couldn't find Garmin software to just write a GPX file, but get301tracks works. Or you can use RoboGeo to download and save GPX.
4. Run RoboGeo ($35). Follow the instructions for "3. From the tracklog in a GPX file". Pick your JPGs, then pick your GPX file, then click "Write the location data to the EXIF headers" to create new geotagged JPGs.
5. Tell Flickr to Import EXIF location data. It's a one time preference setting.
6. Upload your photos to Flickr via your usual method.

There's a much easier way to do all this inside RoboGeo. Just plug in your Garmin GPS, point it at your photos, and upload to Flickr. No messing with EXIF tags or GPX files or anything. But while that's admirable for its simplicitly it's totally the wrong thing for serious image management. You want the raw location on your hard drive so five years from now you can use it again.

The flaw in the above workflow is it doesn't put the geotag data in your raw image originals. RoboGeo supports DNG but not CR2. Ugh. Keep the GPX files around.

Congratulations to the Flickr team for their new geotagging interface. I think this is the first time it's truly easy for normal people to indicate where they took their photographs in a way others can benefit from.

It's a bit late for a pony request, but I sure wish geocoding interfaces had a notion of uncertainty along with location. Ie: latitude, longitude, and radius. A photo geocoded to "San Francisco, CA" is different from a photo geocoded to "659 Merchant St. San Francisco, CA". The former has a radius of about four miles. The latter, 20 feet.

Tagging your photos via a map interface gives a natural radius: a few pixels' width in the map the user clicked on. GPS devices have a natural uncertainy measurement, too. So the data's available, why not store it?

I have about 300 photos from Australia I intend to edit and put online before I leave for France. But as anyone who takes a lot of digital photos will tell you, workflow is still a huge problem. Here's what I do now:

• Stick flash card in a usb device, copy photos as files
• Use Photoshop to convert raw to JPG previews
• Sort through jpegs in ExifPro to find the good ones
• Symlink (by hand) the raw files for the good photos
• Lightly edit raw files in Photoshop, correcting exposure and cropping
• Upload edited photos to Flickr

None of the automatic tools for photo workflow work for me. Either the image edit tools are bad, the database features are too limited, the software is too slow, or the UI is awful. And all of the fancy tools want to store my data in some proprietary database where I can never get at it. The workflow above is manual, but at least the data is transparent.

I was curious about how many tags people put on their photos in Flickr and whether more tags help you get into interestingness. So using their fabulous api I wrote a quick program to count the number of tags for photos in interestingness and compare them to photos in the huge FlickrCentral group. Numbers are averages and standard deviations for both the author's own tags and for tags volunteered by others.

               Author tags  Viewer tags   
FlickrCentral  7.5 (9.1)    0.1 (0.4)
Interesting    8.0 (6.4)    0.7 (2.2)

What's it all mean? Not much. The average FlickrCentral photo has 7.5 tags and the average Interesting photo has 8.0 tags. Well within the standard deviations, not a good predictor. Photos in Interestingness do have measurably more viewer contributed tags but that's not a surprise; photos in Interestingness have more viewers.

So not an interesting result, but I love how easy it is to do this kind of data mining with Flickr.

(For the record, I compared the top 100 interesting photos for each day so far in July, 1900 photos, with the 500 most recent photos in FlickrCentral).

A lot of my photos from Australia have bright blue skies with dark trees in front of them. Like this. One thing that irritates me when editing them is the tree branches have noticeable blue tints.

The problem is the branches are only a couple of pixels wide. And digital cameras aren't true colour sensors, but rather a Bayer filter mosaic of red, green, and blue sensors. So there's some aliasing in the mosaic pattern in the colour sensor. The raw convertor has to be particularly clever to figure out the true colours in the image. To put it another way, a digital camera sensor is going to have a very hard time with colour features only a couple of pixels wide.

Here's a comparison of four raw convertors: Canon's Digital Photo Professional, Rawshooter Essentials, Adobe Camera Raw, and DxO Optics. To keep things consistent I used full defaults for each convertor. So ignore the exposure and overall colour, just look for bleed. To my eye the DxO image has the least bleed. The blow-up doesn't look as sharp in DxO, but I think that's actually more faithful to the reality.

Tinkering around I think I can get the best-looking image out of DxO. It has lots of fancy camera body and lens-specific corrections and, apparently, a smarter demosaicing algorithm. But this kind of pixel-peeping doesn't make me a better photographer. And DxO is a pain in the ass. So I'll just stick with Photoshop. Still, the technological differences are interesting.