In this walkthrough we will use TIGER/Line data from the United States Census Bureau and raster elevation data from WorldClim to load US state and elevation data onto the map. Using the Data-Based Vectorize and Grid-Based Vectorize Tools, we will create vector features representing an elevation range in a selected state. We will then find all occurrence records that occur within each created vector feature.

This walkthrough uses external state data for the United States, and so requires occurrence data to exist occurring within the United States as well. Variations of this walkthrough can be can be completed using equivalent data for other countries.

Step 1

Download the US state shapefile from the TIGER/Line data from the United States Census Bureau. This can be found in the STATE directory of their FTP Archive. You can also click this link to download it directly. Be sure to note the location the file is downloaded on your computer.

Step 2

Download the 5 minutes Elevation raster data from WorldClim. You can click this link to download it directly. This file will download as a zip archive. Once downloaded, unzip the archive to access the tif file it contains. Be sure to note the location of the unzipped tif file on your computer.

Step 3

Drag and drop the file downloaded in step 1 over the map to load the US state data onto the map.

Step 4

Once the US state data has been loaded, pan and adjust the zoom level of the map to view the state data better.

Step 5

If you went through Walkthrough #4 and wish to use the same state identified in step 5 of that walkthrough, proceed to the next step. If not, identify a state on the map in which you know of occurrence records occurring. If you are unsure of how to do this, identify the state in which the county you identified in step 4of Walkthrough #3 is located.

Step 6

Click once on the state feature you identified in the previous step to add it to the Shapes Layer. The newly added feature in the Shapes Layer should display over the original feature on the map.

Step 7

Open the Layers Panel by clicking on the Layers Toggle in the Control Panel.

Step 8

In the Layers Panel in the US state data layer added in step 3 (this should be titled tl_2021_us_state if you downloaded the file specified in step 1), click the Delete Layer button to remove that layer from the map.

Step 9

Close the Layers Panel by clicking close icon in the top-right corner of the panel.

Step 10

Click on the Side Panel Toggle to open the Side Panel, click on Vector Tools to expand the Vector Tools Panel, select either KML or GeoJSON in the Vector Tools Panel, and click the Download button to download the selected state feature to a file. Be sure to note the location the file is downloaded on your computer ecause we will be using it later in this walkthrough.

Step 11

Drag and drop the file downloaded in step 2 over the map to load the elevation data onto the map.

Step 12

Once the elevation data has been loaded, pan and adjust the zoom level of the map so that you can easily see the state feature you added to the Shapes Layer in step 6, which should display over the elevation data.

Step 13

While holding the alt key (option key on Mac), click on different areas within the state feature to open an info popup showing the elevation value (elevation values are in meters). You can click the x icon in the top-right corner of any info popup to close it.

Step 14

Identifiy low and high elevation values that you would like to use in the vectorization process. This process will create vector features representing all areas that are within the low and high elevation range that you identify.

Step 15

Select Shapes in the Active Layer Selector in the Control Panel to activate the Shapes Layer.

Step 16

Click once on the state feature you added to the Shapes Layer in step 6 to select it.

Step 17

Click on Raster Tools in the Side Panel to expand the Raster Tools Panel.

Step 18

Select the elevation data layer in the Target Raster Layer Selector in the Raster Tools Panel (this should be wc21_5m_elev if you downloaded the file specified in step 2).

Step 19

In the Data-Based Vectorize Tool in the Raster Tools Panel, enter the low and high elevation values you identified in step 14 into the approprite boxes.

Step 20

In the Data-Based Vectorize Tool, click the Data-Based Vectorize button to create vector features of all areas within the state feature you selected that are within the low and high elevation values you entered. Ignore any browser popup warnings about the page being unresponsive, the process takes a while, but will complete on its own.

The Data-Based Vectorize Tool can vectorize raster data quickly, but can be less accuarte in its processing of larger rasters, such as this one. We will vectorize first using this tool, and then try the Grid-Based Vectorize Tool to see how the two compare.

Step 21

Once the vectorization process is complete, click on Vector Tools in the Side Panel to expand the Vector Tools Panel, and then click the Delete Selected Features button in the Shapes Tab to remove the state feature, leaving only the new feature created in the vectorization process.

Step 22

Select the elevation data layer in the Active Layer Selector in the Control Panel to activate it (this should be wc21_5m_elev if you downloaded the file specified in step 2).

Step 23

While holding the alt key (option key on Mac), click on different areas within the new feature to open an info popup showing the elevation value (elevation values are in meters). You can click the x icon in the top-right corner of any info popup to close it. Note how well (or not) the vectorization process was at vectorizing the value range you had specified.

Step 24

Open the Layers Panel by clicking on the Layers Toggle in the Control Panel.

Step 25

In the Layers Panel in the elevation data layer (this should be titled wc21_5m_elev if you downloaded the file specified in step 2), click the Delete Layer button to remove that layer from the map.

Step 26

Close the Layers Panel by clicking close icon in the top-right corner of the panel.

Step 27

Select Shapes in the Active Layer Selector in the Control Panel to activate the Shapes Layer.

Step 28

Click once on the new feature to select it.

Step 29

Click on Search Criteria in the Side Panel to expand the Search Criteria Panel, and then click the Load Records button, in either the Criteria or Collections Tab (whichever is selected) to load the occurrence records occurring within the new feature.

Step 30

Click on Search Criteria in the Side Panel to expand the Search Criteria Panel again, and then click the Reset button, in either the Criteria or Collections Tab (whichever is selected) to reset the map back to its default state.

Step 31

Drag and drop the file downloaded in step 2 over the map to load the elevation data onto the map again.

Step 32

Drag and drop the file downloaded in step 10 over the map to load the state feature onto the map again.

Step 33

Click on the Side Panel Toggle to open the Side Panel, click on Raster Tools in the Side Panel to expand the Raster Tools Panel.

Step 34

Select the elevation data layer in the Target Raster Layer Selector in the Raster Tools Panel (this should be wc21_5m_elev if you downloaded the file specified in step 2).

Step 35

In the Grid-Based Vectorize Tool in the Raster Tools Panel, enter the low and high elevation values you identified in step 14 into the approprite boxes and select 250 for the resolution in meters.

Step 36

In the Grid-Based Vectorize Tool in the Raster Tools Panel, click the Display Target Box button to display the target polygon on the map.

Step 37

Click and drag the target polygon on the map so that it covers as much of the state feature as possible, any vectorization that happens outside of the state feature will be removed at a later step.

Step 38

Once the target polygon is positioned, in the Grid-Based Vectorize Tool, click the Grid-Based Vectorize button to create vector features of all areas within the target polygon that are within the low and high elevation values you entered. Ignore any browser popup warnings about the page being unresponsive, the process takes a while, but will complete on its own.

The Grid-Based Vectorize Tool is slower, depending on the resolution selected, at vectorizing, but offers a much higher level of accuracy.

Step 39

Once the vectorization process is complete, select the elevation data layer in the Active Layer Selector in the Control Panel to activate it (this should be wc21_5m_elev if you downloaded the file specified in step 2).

Step 40

While holding the alt key (option key on Mac), click on different areas within the new feature to open an info popup showing the elevation value (elevation values are in meters). You can click the x icon in the top-right corner of any info popup to close it. Note how well (or not) the vectorization process was at vectorizing the value range you had specified.

Step 41

Repeat steps 37 and 38, repositioning the target polygon over different areas of the state feature until the entire area of the state feature (and any additional area) has been vectorized.

Step 42

Once the entire area of the state feature has been vectorized, in the Grid-Based Vectorize Tool in the Raster Tools Panel, click the Hide Target Box button to remove the target polygon from the map.

Step 43

Select Shapes in the Active Layer Selector in the Control Panel to activate the Shapes Layer.

Step 44

Click once on each the new features created from the vectorization process to select all of them.

Step 45

Click on Vector Tools in the Side Panel to expand the Vector Tools Panel, click on the Shapes Tab to select it (if it isn't already), and then click the Union button in the Union Tool to combine all of the selected features into one.

Step 46

Select state feature layer that you added to the map in step 32 in the Active Layer Selector in the Control Panel to activate it. It will be named the same as the filename in the Active Layer Selector.

Step 47

Click once on the state feature to add it to the Shapes Layer.

Step 48

Select Shapes in the Active Layer Selector in the Control Panel to activate the Shapes Layer.

Step 49

Click once on the state feature and the combined vectorization feature to select them both in the Shapes Layer.

Step 50

In the Intersect Tool in the Shapes Tab, click the Intersect button to create an intersect feature of the state and combined vectorization features.

Step 51

Click the Delete Selected Features button in the Shapes Tab to remove the state and combined vectorization features, leaving only the new intersect features created in the previous step.

Step 52

Click once on the intersect feature to select it in the Shapes Layer.

Step 53

Click on Search Criteria in the Side Panel to expand the Search Criteria Panel, and then click the Load Records button, in either the Criteria or Collections Tab (whichever is selected) to load the occurrence records occurring within the intersect polygon.