Four Mapping Mistakes That Affect Data Quality

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The Habitat Network is a citizen-science tool that helps us understand more about how to increase the ecological value of the places we live. Maps are critical for collecting useful data to answer ecological questions because they provide information about the location, the sizes, and the relationships between certain objects and various types of land use, all in one easy-to-understand package.

Mapping is an excellent way to understand your existing yard, garden, or natural area more deeply and to plan for habitat improvements around your home as well as your community. By avoiding the following four common mistakes on your map you’ll get a more accurate readout of how much of the environment is dedicated to individual habitats. For example, if you want to achieve the goal of reducing your lawn to 20% of your property or increase pollinator habitat to 40%, you have the data and visualizations to do that, but only if your map is accurate.

Mistake 1: Not mapping the whole property.

1A

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When creating a Habitat Map, it is important to map more than just the yard or garden. The property as a whole, and how much of that property is allocated towards various types of land use, is of greater interest because it allows researchers to understand how all the space managed by a property owner is put to use, not just a small piece of the overall puzzle. Whether it’s a farm, a suburban home, or an apartment with an elaborate balcony garden, it is important to include all of the parcel that the owner is responsible for. Each “Site” should have one line encompassing the entire extent of the property including all buildings, driveways, gardens and lawns. This “Site Line” is like the folder that will hold all of the information you provide for your site.

1B

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Here, the same site has been properly outlined with the House-Yard site line tool. The line follows the property boundaries and includes all the trees, shrubs, buildings, and lawn from the back road to the front sidewalk. Now, everything that gets placed inside this site line will represent a proportion of the total land use.

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If you aren’t sure exactly where the boundaries of your parcel are, it can help to switch to the “map” view (circled in red above). When you switch, you may find that Google Maps provides the boundaries of your parcel right there on the map, which you can then trace.

Mistake 2. Not using Habigons to completely cover your site area.

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Insider knowledge: “Habigon”= Habitat + Polygon

Habigons are what we call the polygon shapes that are used to map the habitats in your yard. Habigons are what divide your property, outlined by the site line, into measured proportions of land use. Every square foot inside the site line should be covered with some sort of Habigon.

Often, these Habigons get used simply as markers or tags that just represent that the owner has these habitat types in their yard. “I have some lawn here. There is a garden over there…” This is not enough as it does not accurately depict the actual amount of area the habitat covers.

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A map that provides accurate and helpful data will have the entire site line filled in with one type of habigon or another. Choose the habitat tool that matches the actual habitat. There are several to choose from and hovering over one with your mouse reveals a description of the habitat and how you can recognize it. Zoom-in and pan so you can draw lines closer to the actual habitat boundaries as possible and close the gaps between the habigons. If your yard has changed since the satellite image was taken you may need to improvise a little to be accurate.

Mistake 3. Not mapping buildings.

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Insider tip: Zooming-in is key to creating a really good map. Double click to zoom in, or use the zoom-bar in the upper left.

Houses and other buildings play a larger role in the ecology of your yard than you may think. They are often impermeable surfaces which means they shed water to the surrounding environment during rain storms, increasing the amount of moisture the surrounding habitat receives. A building’s roof, depending on the material and color, also contributes to albedoopen_in_new, reflecting or absorbing sunlight and heat, which directly impacts energy consumption. This includes houses as well as garages and carports, greenhouses, barns, and any kind of shed.

In the example above, a couple of the small buildings on this property have not been mapped. The lawn habitat goes around them and, as a result, the Habitat Overview is not accurate. The amount of lawn is not all accounted for, the building data only shows 10%, and the amount of area not yet mapped is increased, making the map incomplete.

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After the buildings have been added, the Habitat Overview reflects a more accurate representation of the proportions of your yard, giving valuable data and providing you with the information needed to assess or plan your habitat improvements.

Mistake 4. Overlapping habigons.

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Some yards contain many habitat types while others may contain only a few. Sometimes they may be clustered together or spread out across a large expanse of lawn. Either way, the layout may be difficult to map and as a result the habitats get overlapped. Overlapping habitats do not accurately define the proportions of the yard, and the combined areas can add up to more than 100% of the Total Site Area, making the map appear more complete than it is.

In the example above, the lawn habigon overlaps heavily into the garden and forest habigons. It also covers some of the pool and both buildings, dramatically increasing the percentage of lawn reported in the overview.

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This can be avoided by using the zoom-in and pan functions to work closely with the habigon lines, bringing them together like puzzle pieces. You can see how the above map doesn’t include any overlapping habigons, making it a more accurate representation of the site. In fact, you can even use the white dots from a previously mapped area as a guide for the new abutting area by selecting the new habitat type and lining up each dot of the abutting habitat to the existing line.

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Sometimes it may be necessary to divide up a single habitat into several habigons in order to include objects that intersect the habitat, like sidewalks or a walkway through the garden. Each similar habigon could be labeled differently (ie. East lawn, Gardenplot#2, etc.), facilitating future organization and planning efforts. Can you spot the difference between the two maps above? Check out the sidewalks on the lower edge of the map. It isn’t easily noticed, but it makes a difference.

There are a myriad of skills and techniques that can help you to create the most complete, accurate, and useful maps possible. Refer to the Mapping tag at the top of the page and keep checking back as we continuously add articles that address user ability topics like this.

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