Catching up – labs and tutorial
Geotagged photos – issues with iPhone
For your second assignment, geotagged photos are to be included for question 5. If you are having problems getting your photos to work in GPSPrune, use the photos Scott has at:
Question 3 in the second assignment
Scott will demonstrate drawing data in both a clean data method and a non-clean method. From this we can see how certain methods employed by GIS Software can produce improper results. This is a reminder to be mindful when creating data.
Zipping your digitization for you TA
Scott will example the zipping procedure, but using the following steps should work to get your data ready to email to your TA.
- Navigate to the folder you have saved your shapefile
- highlight the necessary files by holding down the ctrl button and selecting (4 of them)
- right click on the selected files
- choose 7zip from the menu –> add to archive –> provide a file name
- a new “zipped” file should be present in the folder ready for email
Using your geotagged photos in QGIS
We have been using GPSPrune to convert our geotagged photos into KML/KMZ files. Those files can then be brought into QGIS. Until recently, this was one of a few ways to get geotagged photos into GIS Software, but now many GIS Desktop software can import geotagged photos without the help of GPSPrune.
Loading the photos into QGIS directly
Under the processing toolbox there is a processing tool called “Import Geotagged Photos”. You can find it by typing photos in the search bar of the processing panel. Check it out by loading the folder you have photos in on your K: drive and see how it works. You can also put a web basemap in to see were the points are geographically.
Collecting Tracks and Waypoints (points of interest) using mobile phone apps
We have been struggling with iPhones so far for spatial data collection, but hopefully this will not be one of those cases. Perhaps others will have better luck, but to find an App that does not cost money and provides data for free (free maps) was no easy task for iPhones (but we have some solutions). Finding and managing data on Android – no problem (not saying Android does not bring problems of its own).
Download OpenGPX Tracker from here
This app is quite simple. It has a map interface using Open Street Map (OSM) or Apple imagery. The OSM data can be cached to take in the field. We are really only interested in collecting tracks and maybe waypoints.
Install the app –> turn on location services for the app (on be default) –> Turn on the app –> click the start button –> you can stop, start. pause tracks–> click on the folder in the top left to see the tracks –> press tracks to share via email.
Download GPS Logger from here
This app is super simple – so simple it has no map interface. If you feel you need an interface, download OSMand~ or even better GeoPaparazzi (because not all paparazzis are evil). You can talk to Scott about these apps if you wish to install them outside of the Play Store.
Turn on Location Services (device only) –> Install the app –> turn it on (outside) –> click tracks –> start walking. You can play with the settings to decrease sampling, manage tracks to save the tracks and to share (email). You can also collect waypoints (hit the placemark button on the bottom left).
GNSS data into QGIS
If we were using Garmin (or other units) we could plug them directly into the computer to read from them (you can do this with an Andriod – but we will humor the iPhone users by using email), but using our cell phones means we have to email the GPX files saved from the device to ourselves. There is no need to convert the GPX data for use in QGIS however as it accepts GPX data natively. Just add it as vector layer (you only need the tracks and track points.
Once you have put the GPX file in a folder, we can add it like any other vector layer into QGIS. Unlike Shapefile, GPX files can have more than one feature type – but they do not store polygons. In fact they only store point locations, they just assemble the points into lines (tracks lines). Cleaning the tracks to have lines that make sense (no overlap etc) is the same as editing any other layer, but you cannot edit them as a GPX. You need to save them as a Shapefile.
Your next tutorial task
As with the geotagged assignment, download one of the apps suggested in this tutorial and head out to collect some tracks and waypoints.
Some useful hints:
- Ensure you have your location turned on a start collecting data away from buildings after you have waited for the GNSS (GPS) device in your phone to get a signal
- Try to manage your tracks and waypoints by saving them often (i.e starting and stopping tracks often)
- name your waypoints
- test your results often (email to yourself and try them on osmotar) – We will have more information on GPX files in the lecture on Friday