GPS/GIS Mapping A workshop to develop the skills required to construct maps in Arcmap. Presented by Neil Gray, Teacher-in-Charge, Columboola EEC, (EQ), August 2006.
Components • Garmin GPS and mapping software (MapSource) • DNR Garmin extension software • GIS software (Arcview 9)
GPS • Garmin GPS required for interface with the DNR extension • Garmin MapSource software required for manipulation of field data • Projection in either WGS 84 or GDA 94 • Data collected as either; points, lines or routes.
MapCreationProcess • Plan field exercise and GPS survey process. • Teach students GPS use and basic survey techniques. • Collect field data using GPS units. (This is only position data but it can be linked to any digital data in a quality GIS.) • Save data as points, tracks or routes. Collect other data concurrently. (Digital images, data logger readings etc.) • Remember that GPS data collected is only recreational use accuracy and is only useful for recreational or school educational purposes. If data gathered is to be used in fine detail applications at small scale, or displayed as a layer on top of such accurate data (rasters or satellite imagery at 1:25000 scale or less), it may need to be collected or processed using more accurate techniques than can be covered in this workshop. This is because of the errors inherent in this level of GPS service, that is even though the unit states that it has an accuracy of plus or minus 4m, this is not really true. Factors beyond our control such as clock errors, SV constellation formation, atmospheric factors and other sources of interference, and plain human error, can all conspire to render your readings unusable if compared to very accurate spatial data.
Map Creation Process • Connect GPS unit to PC, open MapSource and turn on GPS. • Down load data to MapSource and save immediately.
All track points have been deleted to enable waypoints to be saved as a data set.
Map Creation Handy Hints • Remember to save each time you have generated a useable data set. • Ensure that the file name is a map feature class, as it will end up on the legend in your map. • Delete all saved data from the GPS before proceeding further. This is because the GPS is actually used as a memory interface between MapSource and DNR Garmin. To delete data from the unit, press the “FIND” button, highlight “WAYPOINTS”, press “ENTER”, to bring up the waypoint list. Press the “MENU” button to access the waypoint manager screen, highlight the “delete” option, press “ENTER” and then select “all symbols”, press “ENTER”. The unit will ask if you really want to delete all waypoints. Select “Yes”, press “ENTER”. To delete tracks and routes from the unit, go to the main menu screen, highlight “Tracks”, press “ENTER”, select “Clear” on the track page, press “ENTER”, the unit will as if you really want to clear the track log. Select “Yes”, press “ENTER”. Any saved routes can be deleted by erasing the component waypoints.
Map Creation Process • Send the required data set to the GPS using the “send to” button. Remember to turn the unit on. • With the unit on, open up the DNR Garmin extension program. It will automatically search for a GPS unit attached to the computer via an open port. • Use the track, route or waypoint option to download the corresponding file. • This will bring up a data list in DNR Garmin. • Send to Arcmap via the save function under the file icon.
Map Creation Process (Cont.) • Sendyour data set to the GPS from MapSource using the “send to” button.
Map Creation Process (Cont.) • With the GPS on, open DNR Garmin and download from the GPS, using the right icon.
Map Creation Process (Cont.) • The waypoints have now been transferred into Arcmap and have therefore been mapped. • This process can now be followed from the start to add more features to your map. • The regular functions of Arcmap can now be used to generate a map of publishable quality (adding a legend, grid, north arrow, title etc.) Arcmap skill building is another workshop. • If your Arcmap skills are developing well it might look like this effort.
Map Creation Process (Cont.) • Note that if you are producing a map based on a blank page the projection used is not important. The default of WGS (World Geodetic System) 84 is OK. • If you are using an underlying raster data set layer, or satellite image you will need to match projections and maybe even calculate position errors and adjust the data accordingly. • Hyperlinks to other digital data can be included in the map projection for each data set. This is a handy feature for digital presentations.
The original GIS project at Columboola was based on mapping a small plot of land using digital maps and satellite imagery. Out at Columboola (Miles), quality digital maps and satellite images are next to non-existent, or they cost a lot of money to acquire. This made it next to impossible to deliver the intent of the original project. There had to be a way to cheaply and effectively use GPS in the field and display the data as a quality map. The release of the DNR Garmin interface for Garmin GPS to Arcmap has revolutionised the nature of generating maps from field data, and its free availability means that even primary school students can now record the results of their field work as a quality map. Compare that to pencil and paper mud maps! The Dulacca SS project required a term for the entire exercise, and only the map produced has been used here. The students produced a brochure including photos, information and the map for the surrounding major vegetation types. About 6 hours of class time was spent learning to use the GPS units, a day of field work, 1 full day to make the map and 6 weeks of timetabled class time to research and make the brochure. The reserve map is the result of about 3 days of intensive field and Arcmap work. The result is infinitely better than the old hand drawn map and useful too. I can now project orienteering points onto the digital map and print individual course maps! The students use their GPS units to find each loaded waypoint in a rogaining style event and monitor the map screen to help claim a “find”. The GPS units track the students for every step that they take, and when this is downloaded to MapSource on their return, I can see the exact route taken on screen, as well as whether a waypoint was “found”. I can even print out the exact track that they walked on the map as a record of their achievement! The GPS units and software have also been used in GPS orienteering in Yr 8, 9 & 10 HPE at Miles SHS, and in senior maths A in the mapping and surveying section of the curriculum. Columboola EEC now “owns” a geocache and caching is included in our curriculum. GPS and spatial ICT’s have revolutionised the way geographic information can be used in the HPE, Maths, Science and SOSE curriculum areas out here in the Miles Cluster. The Final Word