Archive for the ‘News’ Category

GIS Training book done!

Monday, June 9th, 2014

We’ve finished the learning GIS via QGIS  book and it is in the process of publishing.  We’ll let you see the pre-design cover and tell you that it will be available on AMAZON soon!

The authors are Nik Freeman and McCartney Taylor. (Note: the important author goes last)

 

The book is a workbook that evolved from our training courses over 3 years. It will be aimed at the beginner, walk them through important concepts, then give them data and start using QGIS to make a map.  The formula was very successful in training hundreds of Oil and Gas people in how to use basic GIS. And it saved thousands of dollars by showing them how they can use the free QGIS instead of ESRI.

Expected release date June 30, 2014.

gis-book-cover

QGIS Just a few quick tips

Wednesday, August 14th, 2013

Here a few quick tips I wanted to share in QGIS. Under Vector>Analysis Tools there is the basic statistics tool. What it does is fairly simple, but it often gets overlooked.  This will give you data such as mean, median, mode, standard deviation and range. Be careful when choosing the correct column. I noticed that I can choose st_name and it will still try and return results.

Screenshot from 2013-08-14 15:26:54

 

Another is creating labels in Qgis. There are actually two ways to do this. Each way allows you to d different things.  You can download plugins to give more functionality. First and the one I use the most is under layer>labeling

 

Screenshot from 2013-08-14 15:32:05

 

Screenshot from 2013-08-14 15:33:40

This is the layer menu that gives me the most functionality. And it maybe different for others. It gives a sample of the labels being created and provides a lot of advanced features. I tend to use this when I am mass labeling something or I need them to look really good for something such as a presentation.

The other way to create labels is to right click on the layer>Properties> and the labels tab.

Screenshot from 2013-08-14 15:37:40

This I can use for something quick or just a few labels. But even under the advanced tab you lose some of the functions. Such as being able to suppress labeling certain features.

Next under Vector>Geometry Tools> Export/Add Geometry columns. This is simple. It will give you area and perimeter and the options are to either save the results to a new shapefile or add to the current one.

Lastly is editing from the attribute table. This isn’t really editing, but you can delete features. Again this is another simple one, but often overlooked.  In the attribute table at the bottom you have the editing pencil. Once editing is turned on you can now change information in the attribute table and by hitting the red x you can just delete features that way.

Screenshot from 2013-08-14 15:42:32

QGIS Sextante Plug-in

Wednesday, August 14th, 2013

In QGIS there are 100’s of plugins available. One of the best I have used is the SEXTANTE plugin. You can download this by going to Plugins>Fetch Python Plugins and search for SEXTANTE.

Once downloaded it should create it’s own menu called Analysis. I just clicked SEXTANTE toolbox and this is what it looks like.

 

Screenshot from 2013-08-14 15:12:34

SEXTANTE can be literally thought of a as toolbox. It has almost everything you need. In the options you can choose to turn on the listed tools.  Some of the options are modeler, the QGIS tools such as interpolation and DEM analysis are included. Tools for LiDAR database management, creating scripts and the list goes on.

Screenshot from 2013-08-14 15:14:31

 

 

Solving Issues Downloading Qgis for Ubuntu 13.04

Wednesday, July 17th, 2013

I downloaded Qgis for Ubuntu 13.04 and I encountered a few issues.

First issue I had was that I was not able to download any plugin-ins. Second issue is that I was having is that I was not able to download and use the sextante plugin after solving my initial problem.

Before starting I would do a clean install of Qgis if you have been having problems

sudo apt-get purge qgis

If you having issues downloading plugins:

I found this tutorial online and it is from a few years ago but the step to remove the directory worked for me.

http://northwestspatial.com/wp/?p=395

Change to your home directory in the terminal, if you need help with the terminal see the Ubuntu documentation 

 

~cd

ls -la

sudo rm -Rf .qgis

 

What these commands will do is delete a read only file that is put on your computer during installation preventing you from being able to download plugins. There is a more detailed explanation in the link.

 

To download the sextante plug-in:

If you want to use all the parts of the sextante plugin, make sure you have grass installed: http://hub.qgis.org/projects/quantum-gis/wiki/Download and make sure you have SAGA installed. You can get SAGA from the software center or online http://www.saga-gis.org/en/index.html.

If you are getting the error that you are missing psycopg2 you have two options

First try and download it from the software center

Screenshot from 2013-07-17 13:57:08

 

Then in the terminal:

sudo apt-get update

Then open up Qgis and see if you are able to get the plugin.

 

If this does not work for you and when you try and download from the software center it give you an error then here is the process to get around that

In the software center look for the synaptic package manager

Screenshot from 2013-07-17 13:59:11

 

 

What is allows you to is download any updates or repositories needed as a sudo user with a GUI interface

In the search box look for the update: I just typed psy and it came up in the list

Screenshot from 2013-07-17 14:01:11

 

Click on it, check mark for installation and then Mark all upgrades

 

Then in the terminal

sudo apt-get update

Then open Qgis and the plugins should be available.

If you have any questions please feel free to post in the comments below.

 

Working with DEM Models Qgis Quantum GIS

Thursday, July 11th, 2013

Below you will find a few tips on working with DEM models in Qgis. Image taken from http://earthexplorer.usgs.gov/ of Big Island Hawaii

You download your GeoTiff file and it looks like this:

 

Screenshot from 2013-07-11 09:52:36

 

 

To fix it right click on the layer>properties>Style Tab. Under contrast enhancement choose StretchtoMinMax

 

Screenshot from 2013-07-11 10:12:55

 

 

 

It should look like this:

Screenshot from 2013-07-11 10:14:08

Still not much but better. This is an image of The Big Island Hawaii . The lighter the color the higher to elevation and the darker the color the lower. Since this is an island the dark is water in this case

Let’s run a few raster analysis tools to learn more about it.

First let’s calculate slope. You can either express slope as a percent or as is. If you have issues when creating your raster analysis and it comes out looking much like a tv screen with static you need to convert the unit of the layer to the units of the map. If you map is in meters then it is 111120. If it is in feet 370400. It is input whenever you see this box here:

Calc

Slope as a percent:

slopeaspercent

Slope

 Slope

For this exercise I used a scale of 111120 to convert it to meters

Next we can add contours to the map:

Raster>Extraction>Contour

When choosing an interval be careful. It is going to generate a line shapefile that can be very large so just play around and see what work for your project and make sure to include it somewhere on the map or you can label the contour lines also.

I used 100 meter intervals to create this map. I also turned off the layers so it can be seen better

contour

These are just a few of the tools available in Qgis. Feel free to leave a comment requesting help or any other tutorials.