NRM 3300 Clean up Contours, Symbolize & Export Layout

Texas Tech University, NRM, GIS Videos

15 Sept 202419:57

Summary

TLDRThe lab session focuses on refining contour maps using specialized GIS tools. Participants learn to eliminate small polygons that clutter the map and hinder clarity, using a 'Eliminate Polygon' tool with a specific area condition. They also smooth the contours for aesthetic appeal. The session guides through symbolizing the map with graduated colors and applying a 'paper cut' style for a three-dimensional effect. Finally, participants add a color gradient and credits, and export the map as a PDF, showcasing their skills in creating professional-looking elevation maps.

Takeaways

🖼️ The lab focuses on refining a map, specifically adjusting contour lines and eliminating small polygons to improve the map's clarity and usefulness.
🎨 The instructor guides on changing the symbology of the map to 'single symbol' and making it hollow to visually deselect and prepare for editing the map features.
✂️ A tool called 'Eliminate Polygon' is introduced to remove small, unnecessary polygons that clutter the map and detract from its overall quality.
📏 The size threshold for elimination is determined by measuring a representative area and setting a limit (14 square kilometers) to ensure only the smallest, non-essential features are removed.
🔍 The importance of leaving larger, defining polygons intact is emphasized to maintain the integrity of the map's features.
🛠️ Another tool, 'Smooth Polygon', is mentioned for refining the contours, although in this case, the instructor decides it's not necessary due to the already smooth appearance of the contours.
🗂️ The process of cleaning up the map's catalog by deleting unnecessary layers and renaming the final contour layer to 'Texas Contours' is detailed.
🌈 The use of 'graduated colors' and 'equal interval' classification in symbology is discussed to enhance the visual appeal and readability of the map.
📄 The instructor demonstrates how to add a 'paper cut' style from a living atlas to symbolize the contours, creating a unique 3D effect that represents the elevation data.
🎨 Tips on customizing the color scheme to better fit the geographical and thematic context of Texas are provided, including adjusting hue, saturation, and value for a more representative map.
📝 The final steps include adding credits and a scale to the map layout, ensuring proper attribution and providing users with a reference for map interpretation.

Q & A

What is the main task discussed in the lab video?
-The main task discussed in the lab video is to refine and process contour maps, specifically eliminating small polygons and smoothing the contours to improve the map's appearance and utility.
Why is it difficult to edit the contours directly in the provided map?
-It is difficult to edit the contours directly because all the contours have the same elevation, making it hard to work with them in modify mode without a special tool.
What tool is suggested for eliminating small polygons in the map?
-The tool suggested for eliminating small polygons is 'Eliminate Polygon', which can be found under the Analysis tools in the software.
How does one determine the appropriate size to eliminate small polygons?
-The appropriate size to eliminate small polygons is determined by measuring an area on the map and then setting a condition in the 'Eliminate Polygon' tool to remove polygons below that size.
Why is it important to uncheck a certain option in the 'Eliminate Polygon' tool?
-It is important to uncheck the option that considers only polygons that are not within a larger polygon because the small polygons in question are inside larger ones, and checking this option would result in no polygons being eliminated.
What is the purpose of the 'Smooth Polygon' tool in the context of the lab?
-The 'Smooth Polygon' tool is used to refine the contours by smoothing out the lines and polygons, which can enhance the visual appeal and accuracy of the map.
How does the 'Paper Cut' style enhance the visualization of the contours?
-The 'Paper Cut' style enhances the visualization of contours by displaying them as stacked layers of paper, which provides a three-dimensional effect that makes the contours more visually engaging and easier to interpret.
What is the significance of ensuring all contour lines are closed when using the 'Paper Cut' style?
-Ensuring all contour lines are closed is significant when using the 'Paper Cut' style because it allows the contours to be visualized as solid, stacked layers, which is essential for the style to work effectively.
How can one adjust the color scheme to better fit the Texas map in the lab?
-One can adjust the color scheme to better fit the Texas map by using the 'Format Color Scheme' tool to modify the hue, saturation, and value of the colors to match the geographical and climatic characteristics of Texas.
What are the final steps for preparing the map for export as discussed in the lab?
-The final steps for preparing the map for export include adding dynamic text for credits and scale, adjusting the layout, and exporting the map as a PDF while ensuring all processing operations are complete.

Outlines

00:00

🗺️ Editing Contours in GIS

The speaker begins by addressing the final part of a lab, focusing on refining contours in a GIS project. They acknowledge that the participants' colors may vary but are generally pleased with the contour appearance. The main task is to eliminate small polygons that are not needed, which requires a special tool due to the uniform elevation of the contours. The speaker guides the audience to modify the symbology to 'single symbol' and 'hollow' with 'no color' to make the editing process easier. They suggest measuring an area to determine the appropriate size for elimination, aiming to remove features that are more of a hindrance than helpful. The 'eliminate polygon' tool is introduced, with a condition set based on the area size, ensuring not to eliminate polygons that are part of larger features. The process is run, and the results are checked by unchecking the layer to reveal the cleaned-up map.

05:00

🔧 Additional Operations for Map Refinement

After eliminating the unnecessary small polygons, the speaker proceeds to another operation, the 'smooth polygon' tool, to refine the contours further. They emphasize that while the contours are already smooth, this step is educational for future use with lines and polylines. The 'smooth polygon' tool is applied to the previously processed data, with a smoothing distance set to half a kilometer. The speaker then instructs on cleaning up the project by deleting unnecessary layers and renaming the final contour layer. The focus shifts to symbology, where the speaker guides the audience to change the symbology from 'single symbol' to 'graduated colors' using the 'quantile' classification method. They also introduce the 'paper cut' style for the contours, which requires adding this style from a living atlas and upgrading the project to use it. The speaker concludes this section by instructing on symbolizing all contours with the 'paper cut' style.

10:01

🖼️ Finalizing the Elevation Map Layout

The speaker transitions to the final stage of the lab, which involves working on the map layout. They open the 'elevation layout' and appreciate the improved graphics operation. The map frame is unlocked, and the speaker demonstrates how to change the map frame from 'Texas base' to 'elevation'. They then guide the audience to symbolize the contours layer using the 'paper cut' style from the gallery, which creates a visually appealing stacked paper effect. The speaker emphasizes the importance of having closed contour doors to achieve this effect. They then instruct on adjusting the color scheme to better fit the Texas region, using a custom color gradient. The audience is encouraged to experiment with color properties to create a unique gradient. Finally, the speaker guides the audience to add credits and a scale to the layout, ensuring proper alignment and appearance. The lab concludes with instructions on exporting the final map as a PDF, with the speaker extending the deadline for completion and expressing anticipation for the participants' maps.

Mindmap

Keywords

💡Contours

Contours are lines on a map that represent areas of equal elevation. In the video, the speaker discusses how the contours turned out well but mentions that they form one large polygon of the same elevation, which complicates direct editing. Contours help visualize elevation changes, and the goal is to clean up smaller, unnecessary contours to improve the map’s clarity.

💡Eliminate Polygon

This is a specific tool used in the mapping software to remove small polygons that are not useful for the map. The speaker explains that it is necessary to eliminate smaller features that do not contribute to the clarity of the map. The elimination process focuses on removing polygons smaller than 14 square kilometers, helping simplify the map's details.

💡Symbology

Symbology refers to the visual representation of data on a map. In the video, the speaker guides the user to adjust the symbology of the map by changing the contour lines to a single, hollow symbol, which makes it easier to manipulate. Symbology is crucial in making maps visually intuitive and readable.

💡Smooth Polygon

The 'Smooth Polygon' tool is used to refine and smooth out the lines of polygons on a map. The speaker suggests using this tool for improving the appearance of contour lines, especially if they appear jagged. This process is shown to make the lines smoother, contributing to a cleaner, more aesthetically pleasing map.

💡Equal Interval

Equal interval is a classification method in map symbology where data is divided into equal ranges. The speaker discusses switching between classification methods, like equal interval and quantile, to adjust how colors are applied to represent elevation changes on the map. This method ensures that the data is evenly distributed across categories.

💡Paper Cut Style

The paper cut style is a unique symbology that simulates the appearance of contours as layered paper cut-outs. The speaker explains how to apply this style to give the map a visually appealing look, showing contours as stacked layers. This style enhances the map’s 3D feel, making the elevation changes more intuitive to the viewer.

💡Map Frame

A map frame is the area on the layout where the map is displayed. The speaker explains that the map frame is adjustable and can contain different types of maps, like base maps or elevation maps. In the video, the speaker demonstrates how to swap the content of the map frame to show the elevation map instead of the base map.

💡Living Atlas

Living Atlas is a repository of geographic data that users can access to enhance their maps. The speaker instructs the viewer to search for the 'paper cut' style in the Living Atlas, which provides various pre-built mapping styles and datasets. It's a useful resource for accessing high-quality geographical data and styles.

💡Graduated Colors

Graduated colors refer to a symbology technique where colors are applied to data in a gradient, often to represent varying intensities of a specific variable, like elevation. In the video, the speaker demonstrates how to apply graduated colors to the map using equal interval or quantile classification methods, adding more visual 'pizzazz' to the map.

💡Color Scheme

A color scheme in mapping is the range of colors applied to different data points or features on a map. The speaker advises the user to select and customize an elevation-related color scheme that suits Texas’s landscape. This allows the map to visually represent different terrain types, such as the Hill Country or the swampy Gulf coast.

Highlights

Introduction to the final part of the lab with a focus on refining contour maps.

Observation that the contours have turned out well with an appropriate number for the scale.

Need to eliminate small polygons that are not needed for the map's scale.

Explanation of the challenge in directly editing the contours due to their interconnected nature.

Use of the 'single symbol' tool in the symbology to simplify the editing process.

Instructions on how to change the symbology to 'Hollow' to make the small polygons visible.

Guidance on measuring an area to determine the appropriate size for polygon elimination.

Setting the condition for polygon elimination based on the measured area.

Unchecking the 'Dissolved' option to ensure the elimination process works correctly.

Running the 'Eliminate Polygon' tool to remove unwanted small polygons.

Explanation of the 'Smooth Polygon' tool for refining the contours' appearance.

Adjustment of the smoothing parameter to achieve a subtle yet effective result.

Cleaning up the catalog by deleting unnecessary layers after processing.

Renaming the final contour layer for clarity and organization.

Switching to graduated colors for symbolizing the contours.

Selection of the 'quantile' classification method for color distribution.

Introduction of the 'paper cut' style for a unique contour visualization.

Instructions on adding the 'paper cut' style from the Living Atlas.

Symbolizing the contours with the 'paper cut' style for a layered effect.

Customization of the color scheme to better represent the Texas terrain.

Explanation of how to adjust color properties for hue, saturation, and value.

Final touches on the map layout, including adding credits and a reference scale.

Exporting the final map as a PDF for presentation.