In this
demonstration, we will focus on three key tasks.
Selecting counties in years, viewing land cover change summaries
and generating a report of the results.
You can access the EVA tool any time at
MRLC together.
By the end of this section, you'll see how quickly you can analyze
land cover change over time, interpret the results, and create a shareable report.
While the NLCD viewer is designed primarily for data access and spatial
exploration, the tools focused on analysis and interpretation
even allows you to summarize land cover change compared to a specific year
and conduct county level analysis, making it ideal
for quick, easy to understand results without GIS software.
When you first open either, the selection controls are located
in the center of the page.
This is where you will choose your state County.
In two years, you wish to compare.
For today's example,
I will be choosing Texas as my state,
Dallas as my county.
In 1985 through 2024, as my two years,
I wish to compare.
Once those selections are made, I select Get Started
and the tool automatically generates the first set of results.
After the results
are generated, the layout of the page updates.
The map appears on the right hand side of the screen, showing where
land cover changes occurred within the selected county.
All the supporting information, including summary tables,
charts and statistics appear on the left hand side of my screen.
You'll notice that the selection controls
moved to the top left of the screen.
This allows you to easily change the state, county,
or comparison years without returning to the initial start.
Page.
As soon as you make a new selection,
the tool automatically refreshes the table,
maps and charts.
The charts on the left summarize gain losses
and net change for different land cover categories.
Gains represent areas where land cover type increased between
the two selected years, whereas loss shows where classes decreased.
The net change reflects the overall difference between those two years.
These summaries are provided for overall land cover,
as well as specific categories
such as urban development,
forests,
wetlands, and agriculture.
In addition to the charts and tables, even includes
detailed legends which are accessed through the separate legends tab.
Selecting this tab provides context and explains
exactly what the gain and loss categories mean.
For example, when viewing forest gain and forest
loss, the legend clarifies how forest is defined in NLCD.
Forest refers to the presence of trees
on the landscape based on ground cover, not land use.
Only areas mapped as tree cover are considered
forest, including tree cover outside of traditionally designated forest areas.
The legend also highlights why forest cover is important,
including its role in water quality,
stormwater management, and overall watershed health.
It also outlines.
How forest gain is represented.
Forest gain represents areas that changed from non forest
class to forest between the two years.
While forest loss represents areas that changed from forest
to non forest class, these definitions help ensure that the charts and maps
are interpreted consistently and accurately.
As you review these results, you can also adjust
the base maps on the top right hand corner of your screen.
Switching between
imagery and reference based maps can provide additional context
and help you better interpret land cover patterns
and change.
In addition to exploring results on screen,
Evo also includes the ability to generate a report.
You can download a summary report that captures the maps,
statistics, and charts from your analysis.
These reports are useful for documentation, sharing results,
and incorporating findings into presentations or
planning documents.
Together, these features make EVA a powerful tool
for analyzing land cover change and communicating results clearly
all without the need for specialized GIS software.
That brings us to the end of our overview
of the annual MRLC viewer and NLCD Eva tool.
If you have any questions after today's webinar
or need assistance using the MRLC tools, here's how you can reach us.