What’s all the racket? These little artifacts along the edge of the data look like they should be considered nodata however they show up despite setting the nodata to be transparent. Turns out these cells are slightly off-white and were likely introduced during JPEG compression. This can happen with both 0 (black) and 255 (white) nodata values.
Data driven pages allow you to easily create multi-paged map books from one map file that are consistent in appearance. It will definitely make your life easier if you have to break up an area into multiple maps for better viewing of data. For instance, 1:20k maps along a 500km corridor feature, such as a river or pipeline, or 1:10k maps covering a whole municipality.
I’m heading to beautiful Vancouver this evening to attend the Canadian Open data Summit Tomorrow! I’m very excited to be able to give a lighting talk about open data and how we can make it even better! Disparate Data, Technology Fiefdoms (and 65 pictures of your cat) Up in the frozen wastes of the North, […]
It is not uncommon for raster data to be large and unruly. Creating tiles is one way to deal with these large datasets and speed up rendering. This post introduces a few handy tools for dealing with raster data while walking through the process of combining multiple raster files to create tiles for a super-overlay […]
In consulting you really have only one thing: the ability to identify problems. Sure, you may be a UI rockstar or have some mad statistics skills, and perhaps thats why you think your clients call you. Without being able to tease out the real problem, however you will likely not satisfy your clients demands […]
>_ wget www.startupprincegeorge.ca >_ cd /pghacks >_ ./configure build a better PG, one object at a time 0 10 20 30 40 50 60 70 80 90 100 – done >_ make
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I wrote up how to build a US Census Tract database earlier. However, we all know that data without a way of showing it on a map, is a little sad. So I wrote up the process I used to make it all available on a Google Map. The process involves the use of PostGIS, Mapnik, […]
When talking with clients there is always a turning point in my mind where their request turns from being a “Google Map” to being a “web mapping application”. It is usually where data is being filtered, updataed, or when ‘users’ are mentioned. This a pivotal point where the project both gets more interesting, a lot […]
This article shows how you (yes, you!) can build your very own US Census Tracts PostGIS database. I had looked over the interwebs for some time under the false assumption that someone, somewhere would have already done this, but it seems not. So this article documents my process. I am running a mac, so some […]
