Open source versus private licencees for GIS

Introduction

What is GIS? GIS stands for Geographic Information System as it relates to mapping technology.  Basically, it is using computer software to analyze geographic data.  Christopher Gold from the University of Glamoragan wrote in an article What is GIS and What is Not? that the most important concept to comprehend is scale and geographic location. He said that GIS modeling is when the viewing of the model changes the readers perspective, not where the model moves or rotates like in CAD for example (Gold, 2006).  The idea being that GIS is not just the software but the relationship between the data and what the potential products are. That just putting together a picture and calling it GIS is not the same thing as provided a valuable graphically representation of spatial data that serves to illustrate a particular point or direct the viewer into reaching the desired conclusion of what the data is saying.

Open source systems are intertwined within the world of unmanned operations.  It is especially evident for entrepreneurs and innovators within this field.  Open source can be the bridge between conception and reality.  Where private sector software can provide stable reliable interfaces and relate-able analysis of GIS data, open source could bring new angles or ways to analyses the data that have not yet been advocated for.  Thus, bringing about a future of conceptual ideas much faster by not having to wait for software to be designed and licensed like in traditional software suites.

Using Qgis, an open source GIS software package, the Digital Surface Model (DSM) on the left was created. The process for creating this image with Qgis was very similar when using another paid software, called ArcMap, to create a similar  rendering. On both applications, the data was loaded into the software either by directing the file path to the information or by using a "drag-and-drop" method.  Again on both applications, the open source and proprietary, an extension was downloaded to to manipulate the original data to show elevation changes clearer using a function called hill-shade. The original image is shown to the right for comparison of what the hill-shade feature does to the image. Both of the above images where developed through the use of Qgis open source software. The two maps below show a side by side comparison of the final product from the two types of software that was used to create them. The first map was done using ArcMap, while the second was done using the free Qgis software.

One feature from Qgis is to assign and modify color bands to an image. To do this, I first navigated to where I had saved the data and opened the files, the data that had each individual bands saved as different images. Then, using the merge raster GUI, i assigned bands to the different individual layers to represent red as showing healthy vegetation. I did this primarily by hiding the green band and emphasizing the red and yellow bands. This false color stacking of a sample data set can be seen in the map below.

Working in the GIS World

Wolf Paving Geospatial Build

The map above was created using data from a UAS. the following is question / answer style report that portrayed the process of creating a GIS map for a random data set. 

Part One:  Background

Q: Why are proper cartographic skills essential in working with UAS data?

A: Data is just data unless it is processed and evaluated so that it can be used to express an idea. Tuning data into maps is a valuable way to express an idea that was captured using UAS. One must possess the proper skills to change raw UAS data into effective maps that communicate the intent of the data.

Q: What are the fundamentals of turning either a drawing or an aerial image into

a map?

A: To turn a drawing or image into a map it must have a scale and legend to give the reader a point of reference.

Q:What can spatial patterns of data tell the reader about UAS data? Provide

several examples.

A: Spatial patterns can show a reader different layers of comparison in the data. The use of color mapping height is one such example where using different degrees or tones of color would bring different objects into focus depending on the intent.

Q:What are the objectives of the lab GIS Build?

A: The objectives of this project were to become familiarized with GIS and how it can dramatically improve the quality of data collected using UAS.

Part 2:  Methods, Creating a map with reasoning behind each steps.

Working with the Data

• Start by copying the UAS data folder shown in the demonstration into your

own folder for the UAS class. Be sure to name and organize accordingly. 

Q: What key characteristics should go into folder and file naming conventions?

a.       Date

b.       Name

c.       Unique identifiers

2Q: Why is file management so key in working with UAS data

a.       UAS files may look similar to each other but represent very different sets of data

3Q: What key forms of metadata should be associated with every UAS mission

a.       Altitude

b.       Type of platform/Sensor

c.       Other optional metadata, pilot name, time of day, Weather conditions.

▪ Create a table that provides the key metadata for the data you are

working with

• Add a basemap of your choice. Save the project with a pertinent name.

Q: What basemap did you use? Why?

·       Road map

o   To give location awareness by using major roads as  guides.

o   Roads also give the reader a sense of scale without using a numerical bar scale

• Using the Add data icon, or Arc Catalog, bring the orthomosaic and the DSM

into ArcMap

• Build Pyramids and Calculate Statistics for each data set.

Q: What is the difference between a DSM and DEM?

              DSM -digital surface model (includes objects on the surface) i.e. man-made objects.

              DEM- digital elevation model (does not include objects on the surface) i.e. terrain

• Go into the Properties for the DSM and record the following descriptive

statistics.

o Cell Size, Units, Projection, Highest Elevation, Lowest Elevation

o Enter those statistics into a table. 

Q: Why are these important?

              Gives the reader data they will need to compare relationships within the map or image.

• Generate a Hillshade for the DSM. Then set the original DSM to a color ramp

of your choice and set its transparency to your choice over the shaded DSM.

Q:What does hillshading do towards being able to visualize relief and

topography.

A: Enhances terrain associations that are differentiated by elevation.

• Use the swipe tool to compare what you see in the orthomosaic to the DSM.

Q:How does the orthomosaic relate to what you see in the shaded relief of

the DSM

A:  It adds context to the shaded relief.

• Save your ArcMap project again (in case the software crashes). Open

ArcScene.

• Add the DSM into ArcScene. Zoom to that layer.

• Now add relief by setting the base heights to the elevation value. If needed,

zoom to the layer again and adjust the vertical exaggeration.

Q:What is the purpose of vertical exaggeration? What settings do you have

for your data?

A:  It exaggerates the differences in terrain elevations.

Q: What color ramp did you use? Why?

 A: Red to green. Red is often associated with high and green with low. Makes it more relatable to the reader without having to decode the color scheme.

Q:What are the advantages of using ArcScene to view UAS DSM data vs.

the overhead shaded relief in ArcMap. What are the disadvantages?

 A: Advantages are that the model can be rotated to put emphasis on select portions of the data. Disadvantage is that cardinal direction could be lost and scale could be skewed.

• Find a zoom setting and angle you like in ArcScene and export the image as a

jpeg or file of your choice.

o Is this export a map? Why or why not?

              It is not a map, It would be a map if it had scale and a legend

Part 3: Conclusions

• Summarize what makes UAS data useful as a tool to the cartographer and GIS

user,

              UAS data is a useful tool to the cartographer and GIS user as it opens up aerial imagery as a relatively cheap and easy way to gather data. UAS data, if properly gathered and organized, can be highly detailed and accurate to create extensive useful products  

• What limitations does the data have? What should the user know about the data

when working with it.

1.       Limitations that come with data are that it is only as good as how it was collected. If parts are missing like an accurate coordination system that links the image to a reference-able place, then the data set will be nothing more than an pretty picture.

2.       The user should know the following: how was the data collected, what are the different parts of the data, what was the purpose of collecting the data, and how will the data communicate the message of the final product.

• Speculate what other forms of data this data could be combined with to make it

even more useful.

1.       Historical data

a.       Previous images that show changes over time

2.       Additional ground reference points to depict more accurate terrain changes