Archive for October, 2013

That’s One Short Tutorial: TileMill

Everyone and their brother has been asking for TileMill tutorials. I have zero time for a full-on, production level, quality video series. Sorry. :( But I do have time for a 1 minute long, cell phone attached to a tripod made of Legos, weird screen glare, introduction! Hooray!

I went for the non-screencast format in favor of the friendlier, “I’m actually here” format. If we produce a whole series then we’ll have to switch to a screencast where you can see the screen better. And I’ll have to take that bad*%( microphone down from the top of the bookshelf. Until then…

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Thumbs Up for Graphics Programs

Inkscape is a free open source graphics editor. I’ve been using it quite a bit this week and, while it’s just basic graphics work, it’s a lot of fun. Those of us who came to cartography via the traditional way, GIS, have a particular fear of graphics software. Getting over that, though, opens up a whole new world of possibilities. Ever wish it were easier to move labels around and experiment with different fonts? So much easier in Inkscape or Illustrator! Ever wish you could just quickly re-color an entire map so all the colors were lighter or darker, or apply a weird-effect, or change individual colors without having to click in a symbology editor? So much easier in Inkscape or Illustrator! (Though you can also do some great color effects in TileMill without much effort too.) Have an old map that needs a few tweaks but don’t want to open up the GIS project and re-connect all the datasources? Sometimes you can vectorize an old map like that and simply change it in a graphics program. So many uses for a good image editor, we should all be using one regularly.

(Flipside: cartographers who got into maps from the graphic design field can improve their analytical visualizations, ensure projection perfection, and a host of other things by checking out a GIS once in a while.)

Here I’ve used Inkscape’s Filter called “Moonerize” to change the colors of one of my existing LULC maps to something a bit more…out of this world. Yep, I had to say that.

More realistic, is this little exercise in updating one of the maps from the 1st edition of GIS Cartography. Here’s the original map, warts and all:

What is going on there? Yes, its meant to be a thumbnail but anyone can see that whatever those coastal features are don’t line up with the coasts at all. Almost all the 200+ maps in the book are saved as project files in a neatly organized spot so they’re easy to update. This one, though, was mysteriously missing. Thinking I could quickly re-create the thing using public data had me running into two issues (1) most of the government sites are down right now and (2) sea surface current data is pretty hard to find anyway. And, like I said, the data is nowhere to be found on my local machines either.

Inkscape to the rescue! I made the new basemap in ArcMap and exported it as an svg. Imported that into Inkscape. Then I imported the original image (sized the same as the basemap I just made) into Inkscape and converted the sea surface current data, those black triangles, into their own bitmapped layer (Path>Trace Bitmap), deleted that bad background, and simply superimposed the current triangles onto the new basemap. So much better now:

Figure 6.51 you are now good to go!


Ice Cream and Topology

It is still a crazy time around the office of PetersonGIS. It may appear to be all quiet and calm but the manuscript deadline for the 2nd edition is fast approaching and things are not moving as swiftly as I had guessed. Age-old problem, I know. This is what keeps me motivated, though…the thought of getting myself one of these on THE DEADLINE DAY, Nov. 1, 2013:

Thanks to everyone who has submitted a map for potential inclusion in the book. I’m going to carefully go through all of them just as soon as I can. I was supposed to do that this week but it’s not going to happen. I’ll let you know yes or no just as soon as possible.

Currently on the radar is figuring out just what the heck is going on with ArcMap 10.1. Here’s a map from 1st edition that needs updating…

You can see it’s not entirely topologically correct. In the process of trying to export a new map, Arc wants to convert the dashed lines for the little tributaries to solid lines. But how did I solve the issue back in 2008 when writing the 1st edition? It’s a mystery! The stated workaround according to Esri is to use the symbol property editor but I’ve got these as simple line graphics as my own workaround to another problem. It really never ends. Perhaps when you pick up a copy of the 2nd edition sometime in 2014 you’ll get to find out if I ever solved it. :)

Updated 10 min. later—I’ve just discovered that I can simply save as a lower resolution file to keep the dashed lines. To get around the fact that I need a high res output, I’ve increased the size of the original so that it can be reduced in size proportionally to an acceptable resolution.