Monday, 1 August 2011

Cartographica - GIS for the Mac Platform - 02

Traditionally Geographic Information System (GIS) have been exclusively run on the Windows platform. Only very few applications run on either cross platform or exclusively on the Mac. This is part two of a review and introduction to Cartographica, a Mac based GIS software. Find part one with a general introduction HERE.

Getting data into the Cartographica GIS platform is possible in multiple ways. There are a number of formats directly supported, such as shapefiles and kml. It can be also either a vector, a raster or a table format. To connect to other services and devices there is data base import as well as direct GPS import or WMS (Web Map Service) map data.

Cartographica GeoImport
Image by urbaTick / Screen shot showing the import dialog for tabular data. Here we are importing the Primary school league tables as found on the Guardian Data Blog. The data does not have geo coordinates so we are using the geocoding feature of Cartographica to locate the data via the address given in the csv file.

If you are working with a external data source trying to map some information that comes in a table for example the dialogue will guide you through the steps to identify the different columns, where you have to indicate the location columns and the value columns. It is also possible to use this import option to extend on existing content, by matching two columns to exiting fields and Cartographica will import the additional data to the corresponding data. Also this feature can be used to geocode addresses if you are working with address data.

Once the data is loaded it will be displayed on screen. The next steps will be to either combine it with other data or information, to adjust the projection, to manipulate or to analyse the data.

Cartographica Aerial BingMap
Image by urbaTick / Screen shot showing the imported data with a Bing Map aerial imagery underlay for the whole of England. The points start to make sense as to how they are located in a spatail context.

Cartographica OSM zoom SE
Image by urbaTick / Screen shot showing the imported data with a Open Street Map underlay. In this view we have zoomed into the South East of England. The street information as well as geographic features are visible and annotated.

To combine additional data simply import other sources or add a live map. Cartographica currently offers the option of Bing maps or Open Street Map. Bing maps come as street map or as satellite imagery. Through the WMS any other map can be used in the background. This is brilliant, because with just a few clicks the data can be put in context and read in a very different way. See the data information on a aerial photography background or on an Open Street Map background depending what the criteria is.

The projection can be adjusted for the map or for the layer. Cartographica offers a range of preset projections with the very traditional projections such as Mercator or WGS. There are also a range of country specific projections, but most important, with the hundreds of specific projections out there you can import your own projection. This adds flexibility and accuracy.

Manipulating the data by hand is done in Cartographica using the four interaction tools provided above the main map window. The first one from the left is the zoom element, the second one is the information tool to retrive details from objects, but also to select objects. The third tool is the pan tool to move the map around and the fourth tool is for measuring either area or distance. The very handy thing with the tools in Cartographica is really that it work in good Mac tradition with keyboard shortcuts. Selecting the tool and performing some operation can be done directly from the keyboard. This is really good for doing quick and precise work.

Cartographica Density
Image by urbaTick / Screen shot showing a density overlay calculated from the imported school data set. There is a concentration of school in London as expected.

For the data analysis Cartographica offer again a range of options. There are for example a range of tools to enhance the data like adding the geo coordinates to a point layer that was imported via the address, as in the example above. Then there is als the density analysis tool to create a kernel density from point information. The result is a raster layer representing the density of points. Here the colour scale can be adjusted in much detail. Cartographica is also capable of buffering, creating a distance zone form a feature, either point or line data.

Cartographica OSM Buffer
Image by urbaTick / Screen shot showing each school buffered by a 800 meter radius in Camden and Islington in North London. There is Regents Park and Hampstead Heath as empty areas.

A great feature is also the capacity to plot GPS geo coded images you have, for example from the iPhone. This will provide you with a map of the location of all the images, including a small icon. If you are working on a documentation or have field notes together with picture you have taken this is very handy.

Cartographica offeres a range of powerful basic GIS analysis functions. all at the benefit of simple usage. It is not just easy to use but intuitive as one would expect from a Mac application. In case you are not as familiar with GIS analysis and not quite sure how to do this or where to find this, the online platform offers a tutorial on all features and showcases a range of how to step by step guides. Its a great resource for anything technical in Cartographica.

The software is available form the web store at a price of $495 and as an academic student license for only $99 for one year. This is tremendously good offer, especially if compared to some of the other packages prices. Also the latest version has been optimised for OSx Lion, so you should not experience any problems if you have already upgraded to the new Mac operating system.

In a next part the exporting feature and the mobile version of Cartographica will round off the three part review of Cartographica. Watch out for the next bit.

1 comment:

Anonymous said...

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