Shapefiles are a standard file format for moving geographic data around. If you're using PostGIS, then you can use shp2pgsql to convert a shapefile into the SQL statements needed to reproduce that shapefile in your PostgreSQL database table.
However PostGIS differentiates between a POLYGON and MULITPOLYGON (which is a ...
read moreThere are comments.
It is relatively easy to insert rows from one table that match a certain condition into another table, e.g.:
INSERT INTO table2 (col1, col2) SELECT mycol99 as col1, col2 FROM table1 WHERE id < 1000 AND col2 IS NOT NULL;
This inserts rows from table1 that match the SQL condition ...
There are comments.
Often you might have a table in PostgreSQL and you want to make a complete copy of that table, including all the indexes.
You can copy that table with this command:
CREATE TABLE newtablename ( LIKE oldtablename INCLUDING ALL );
Replace newtablename and oldtablename with the new and old table names respestively ...
There are comments.
The Shuttle Radar Togography Mission (SRTM) is the 'go-to' source for open data for elevation. If you want to make a map that shows hill countours or hill shading, this is a great global, free data set.
There are few ways to download it, but I recently discovered this site ...
read moreThere are comments.
I'm doing a project that involves a lot of PostgreSQL processing. i.e. a lot of relatively simple queries that UPDATE or INSERT a lot of data. Here are some tweaks I've made to my PostgreSQL setting file (/etc/postgres/9.1/main/postgres.conf) to make postgres ...
There are comments.
Looking for the Beatles song: Check Wikipedia's Yes it is page
When looking at my Google Analytics page for incoming search queries, I noticed a lot of people searching for "yes it is", which is a Beatles song from the 1960s. It was a strange thing for people to ...
read moreThere are comments.
I have been doing a lot of PostgreSQL work recently using the psql command line programme as a rapid iteration experimentation process, most of my experience is with MySQL. One feature I miss from mysql command is that it would tell you how long it too to execute a query ...
There are comments.
psql, the command line PostgreSQL tool is great. By default if the output of some command (or query) takes too much screen space, psql will use your default unix terminal pager to page through results.
Sometimes you want to turn this off. This can happen if you want to see ...
read moreThere are comments.
It's possible to install both PostgreSQL 8.4 and 9.1 on Ubuntu. If you find that one of them is running and you want to run the other one to run then just stop postgres with this:
sudo /etc/init.d/postgres stop
Then if you want to ...
read moreThere are comments.
I had created a table in PostgreSQL, but I hadn't added an primary key or unique id field. This StackOverflow question explains how to add an auto-increment field when you're creating the table, but that doesn't work if you have already created the table. I didn't ...
There are comments.
Very similar to my last post about how to set a user password for a postgres account, here's how to create a user account in the first place.
After you have installed postgres:
$ sudo -u postgres createuser
It'll ask for the username, enter the same as your unix ...
read moreThere are comments.
I've mentioned before about using kindlegen & formatting in HTML for kindle publishing (e.g.: How to make a kindle ebook full of images). Recently I had to create internal links within my eBooks. A map is unlike a traditional novel, since it's not a one-page-after-another reading method, more ...
read moreThere are comments.
Since it's actually possible for me to recieve payments, I have started to recieve money from this Kindle Maps adventure.
It's great to be on the road to viable micro-business. All I have to do is several orders of magnitude increases in sales. :)
read moreThere are comments.
I live in Ireland and hence have an Euro demominated bank account with AIB. I have sold lots of things on the Amazon.co.uk store in GBP (Pounds Sterling), and I was suprised at the KDP payment options. However I went ahead and just put my (Irish/EUR) IBAN ...
read moreThere are comments.
Google Analytics is great web analytics/tracking software, and can easily track what pages people go to on your site. I recently updated the front page of Kindle-Maps.com, which included links to all my books on the Kindle Shop, but there are 3 Kindle Shops (Amazon.com, Amazon.co ...
read moreThere are comments.
If you're using jQuery, you can add new selectors to your objects. If you add this to your $(document).ready(...):
$.expr[':'].external = function(obj){ return !obj.href.match(/^mailto:/) && (obj.hostname != document.location.hostname); };
Then you can do things like $(a:external) and operate only on external links. Selectors ...
There are comments.
I use the OpenStreetMap data country extracts from Geofabrik, where you can download individual country extracts of OpenStreetMap files. This is imported into a PostGIS database using osm2pgsql.
Once you have created a postgis database, you can import the file into the same database (but with a different table prefix ...
read moreThere are comments.
I've updated the Kindle-Maps.com front page to accurately reflect the state of play. Adding in links to each book, and screen shots. I'll have to work on conversion optimisation for this.
read moreThere are comments.
One of the great things about Open Data and OpenStreetMap is that you can control what the map looks like. You are not limited to just what the data looks like and you can customise it yourself.
I have made a custom Mapnik style file that's optimized for Amazon ...
read moreThere are comments.
When you publish a book on the Kindle Direct Publishing system, Amazon 'reviews' your book, and you can't click on the 'Actions' button to view it on the Amazon store (nor check what the free sample is like). However you can still see it on the store.
The easiest ...
read moreThere are comments.
Using OpenStreetMap with TileMill can be done with OpenStreetMap Shapefiles in TileMill. However things get interesting if import the data into PostGIS. You have more control over what you want to render (since IME it's easier to change data in a SQL table, than a shapefile), and it's ...
read moreThere are comments.
Mapnik is the most popular renderer of free maps like OpenStreetMap. I hadn't really done much mapnik development, but for Kindle-Maps, I had to make a new style.
One thing that I didn't like was when drawing the text/name for a road was that all the text ...
read moreThere are comments.
TileMill comes with a basic coastline data set, which it calls #countries on new layers. It's great, but it's not very accurate when you zoom in more than zoom 7. OpenStreetMap has coastline data, and it's much more accurate and detailed than the default TileMill one. It ...
There are comments.
When debugging an application that uses PostgreSQL it can be very helpful to see what queries are actually being sent to the server. This can allow you to try running the queries yourself and you can see what results are coming back.
On a normal PostgreSQL 8.4 install on ...
read moreThere are comments.
A lot of the time with PostgreSQL database server you don't use a password, but instead it's based on local unix username. However it's possible to add a password to a user after you have created the postgres account. Just start psql as the postgres user like ...
There are comments.
After you install TileMill, you want to have some data to play with. OpenStreetMap is a great source of freely licenced geo-data for making maps. Probably the easiest to is use the SHP files that Geofabrik provide. Starting off at downloads.geofabrik.de/osm, find the country/area you're ...
read moreThere are comments.
TileMill is a much nicer and easier way to make maps than to writing raw mapnik style files yourself. Their website has an install script which is basically "download this file and run it as root". I never like doing things like that, but the file itself is quite simple ...
read moreThere are comments.
While browsing around the Amazon Kindle Store, I found someone else selling loads of Maps on the Kindle. They have a much larger selection than I do, hundreds of maps. It's good to see someone else validate my theory that you can sell maps on the Kindle.
However from ...
read moreThere are comments.
I have entered the US market! I've made a Simple Little Map of New York. It's similar to the maps of London, Dublin etc., however I've used a new 'auto-zoom' feature, where areas that have a high density of 'stuff' are show zoomed in. This way city ...
read moreThere are comments.
osm2pgsql is the main way to import OpenStreetMap data into a database (e.g. a PostGIS/PostgreSQL database). The old fashioned way to play with OpenStreetMap data was to use the OSM XML file format. However recently Google released Protocol Buffers (aka protobuf aka pbf) a much faster way to ...
read moreThere are comments.
The Python documentation for profile python code, says that to profile/benchmark a python script, you just need to run this command:
python -m profile ./name_of_your_script.py
However on a stock Ubuntu 11.04 Natty Narwall install, you will get an error message saying that the profile module is not ...
read moreThere are comments.
On the unix command line, each command can print to stdout (standard output) or stderr (standard error). By convention, error messages go to stderr, and normal messages go to stdout. You usually connect stdout to the stdin (standard input) of another process. Having a long pipe of commands and this ...
read moreThere are comments.
I'm trying to not pay too much attention to my statistics (either Amazon sales stats or Google Analytics), since it's too easy to waste your time always pressing refresh.
But I was pleased to see today that my Simple Little Map of London is №2 on Amazon Kindle ...
read moreThere are comments.
Since I discovered that Amazon KDP's payment options aren't great for me, I'm refocusing, on the European Market (specifically the UK market, since I don't speak German very well (aber Ich hat für sechs Jähre Deutch gestudiert (sic)). I think I can get paid ...
read moreThere are comments.
In the spirit of openness and sharing (and since I've learned from other microbusinesses online that are open), I'm going to file reports on how things are going. Quaterly is a good benchmark, so I'll start with that.
This quarter was launch quarter when I started. I ...
read moreThere are comments.
PostGIS is an open source geographical/spatial SQL database extension for PostgreSQL. Here's how to set up a database on Ubuntu Linux. (I couldn't remember how to do it last time, and had to waste time googling. I'm keeping it here for record). You'll have to ...
read moreThere are comments.
So I've been selling a few copies of my initial OSM map. Using Amazon's Kindle Direct Publishing, Amazon will pay me for sales from the USA Kindle Store with a USD checque, or electronically (EFT) if I have a USD denominated account. Living in Ireland, I have a ...
read moreThere are comments.
Here at Kindle Maps, I'm trying to make maps from OpenStreetMap and put them on the Amazon Kindle, like an off-line street atlas. EBook readers are great for text because you can reflow the text, and increase the font size, etc. However a street atlas will not have any ...
read moreThere are comments.
If you have several images, it's very easy to create a PDF (on the linux bash shell) of those images using ImageMagick (ubuntu install link). Just us the following command:
convert image1.png image2.png image3.pnf output.pdf
This will create a new pdf output.pdf, where page ...
There are comments.
Previously I mentioned the screen size of a kindle, and I used this to create my PDF of image files. However Amazon's PDF converter messed that up. After examining the HTML source file that amazon created, and especially the images in that zip file, I am now using the ...
read moreThere are comments.
After amazon removed my first book because the formatting was all messed up, I regenerated it with HTML (as opposed to PDF). The .mobi looked much better on my Kindle, so I re-uploaded it. Within 24 hours it was back on sale on the Kindle store. I double checked this ...
read moreThere are comments.
Initially I made a Simple Little Map of Dublin and put it on the Kindle Store. It was going to be a trial of the sort of thing I'd sell here. I just used the default mapnik styling for OpenStreetMap, which I was never happy with, and was going ...
read moreThere are comments.
I've just populated this site with about 6,500 pages from Open Street Map Data, one for each city that I can make maps from. It also has a Wufoo form on each page. I'm hoping these will be suitable landing pages for web searches. However it'll ...
read moreThere are comments.
In order to calculate how to walk across Dublin without passing any pubs, I had to know where all the pubs in Dublin are. I used OpenStreetMap data for the locations of all the pubs.
After publishing that route, many people contacted me asking for the data of all the ...
read moreThere are comments.
I use pv (pipe viewer) on the command line to measure the progress of text through pipes. A great option is to use -l (i.e. pv -l), which measures lines going through the pipe / command chain. Since passing around text and lines of plain text is the core of ...
There are comments.
Sorry, this will be another technical blog post!
As part of this project, I'm processing OpenStreetMap data a lot, and that comes in XML. I've been using STX for this.
STX has variables, and they are mostly simple things like strings and numbers. But you can also have ...
read moreThere are comments.
This blog uses Pelican, a python static blog generator. It is open source and all the source code is on github.
There was an irrating bug (for me), where articles weren't being sorted chronologically. I wanted a recent blog post to show up on ...
read moreThere are comments.
For an upcoming project, I had to know of all the pubs in Ireland. I've been using OpenStreetMap, however it's not a complete project yet, so there might be pubs that are missing. I wanted something offical.
I found a list of all licenced premises in Ireland from ...
read moreThere are comments.
Here's a CSV file of all the cities in the world from OpenStreetMap data. Download now. It's a list of all places that are tagged place=city.
First entry is the latitude, second is the longitude, third is the name of the city. Latitude is a number, positive ...
read moreThere are comments.
Page 1 / 1
has the following screen sizes: