MICRODEM GIS Course Lab 1
With no data open in MICRODEM, go to File, Annapolis GIS data sampler.
If the 900 MB zipped data set is not present, it will be downloaded. It will
set a number of defaults to directories with this data, which will go into
c:\mapdata\annapolis_data
We will not use all this data, but it is easily available for anyone who
wants local data.
Data Layer |
GIS data types |
Directory |
Source |
Importance |
DEM:
3DEP/NED--National Elevation Data |
Raster |
NED |
USGS Seamless Server, July 2014.
This way of getting the data no longer works; we will cover the
replacement method later, from the
National
Map. |
DEM--topographpy has many uses. Better details means either
bigger files or smaller coverage area. |
CONED |
Raster |
land_water_merge_coned |
https://coast.noaa.gov/dataviewer/#/ |
The USGS CoNED Project integrates disparate light detection and ranging
(LiDAR) and bathymetric data sources into a common database aligned both
vertically and horizontally to a common reference system. The
resolution on land is much better than in the water. |
Land Cover: NLCD
2011 |
Raster |
nlcd_2011 |
USGS |
Land Cover. This has a significantly different map projection,
which is part of the reason we will look at it. |
USTopo GeoPDF |
Raster |
UStopo_geopdf |
USGS |
Digital version of the topographic quadrangle maps |
OpenStreetMap |
Vector |
osm_july_2015
osm_dec_2016 |
http://download.bbbike.org/osm/ |
Crowd sourced; amount of detail varies spatially. You could
look at the change in coverage between the two dates. |
TIGER
Edges |
Vector |
tiger_edges |
Census Bureau |
Roads and coastlines. |
Gazetteer |
Vector |
usgs_gazetteer |
USGS NAMES server |
Locations of named features in multiple categories |
Lidar point cloud |
Point cloud |
usgs_las_point_cloud
las_2011_Anne_Arundel |
USGS Earth Explorer |
Both of these are relatively low resolution, from 2004 and 2011.
The 2011 data covers a larger area, and includes point classification
and an intensity image. The 2004 data set shows the temporary
buildings after hurricane Isabel. |
Basics of running
MICRODEM and how to perform common operations.
In this lab we will look at the different types of data manipulated in
GIS software,
combine several layers on a single map, and export maps to Google Earth. The goals of the lab
are:
- Understand the basic map operations in the GIS program
- Introduce the different types of data available in a GIS.
The options available in the GIS program depend on the type of
data.
- Understand how the
KISS
principle used in the design of Google Earth affects its
operations.
We will come back to many of the concepts touched on in this lab, in much
more detail, but want to
see an overview of what GIS can do before we get down in the details.
Deliverables in Blackboard.
In a singleWord document and a single KMZ file. You will correctly label the figures
(caption below) and tables (caption above). The figures will come after
the first reference to them in the text. Make this a discussion (well
written); do not make it a question/answer. The cut and pasted
questions should not be in the deliverable Word file.
- How can you differentiate the UTM grid and the lat/long graticule
from their geometric properties? How are they different on the maps
with the DEM, the CONED, and the NLCD?
- Overlay the TIGER edges on the three NED DEMs. Explain how the road
network differs in the three maps, and why you think this is the case.
You might also consider what happens when you zoom in, or blow up the maps.
This could be a table.
- Get a map with all the OSM layers showing point, line, and area vector
overlays. Comment on what the different layer geometries
mean.
- Get a map showing the locations of all the "schools" from the gazetteer in Anne Arundel
County. Show it on the DEM, use the standard school icon, and perform
an export to Google Earth. Comment on what is counted as a "school" in
this database.
- Comment on the distribution of buildings in the OSM data for this
region, looking especially the regions around Chesapeake High School and
Severna Park High School.
- Discuss how the point cloud helps to visualize the terrain.
In a single KMZ file. This will be organized and labeled so your
audience can turn the layers on and off. The labels should mean something
to a real user, and not just to a GIS geek.
- Anne Arundel County schools, with school symbol icons.
- Anne Arundel County churches, with appropriate symbols.
In a GIS program, there are almost always multiple ways to perform an action.
These instructions will generally give you one way, the links will show you
others.
MICRODEM allows you to open multiple map windows at the same time, which some
other other GIS programs will not. Both MICRODEM and other programs allow you to
stack data sets in layers to build up a complex map, and rapidly change the
display. Plotting order is important; the top layer may obscure layers
under it.
New DEM to open a raster data set
called a Digital Elevation Model (DEM). Open all three of the NED files
which cover Annapolis. Note they are all approximately the size file
size (9-17 MB), but cover regions of very different sizes which you can see
from the scalebars. The data sets have missing data, in the water, but
the effect is not uniform.
- Change display parameter.
Change the display settings when you make this change, or
right click
on the map and select the choice for the current
display option such as Elevation,
Slope, or Reflectance
Grid: put up both a
UTM grid and a
lat/long graticule. You probably want to adjust the color/line
width so you understand them; normally you would only show one, and use
thin black lines. Note:
- Shapes of polygons (are they square or rectangular)?
- Are they parallel to the edges of the map?
- Are they parallel to each other?
Information on the map to see if the
map data had to be blown up, or reduced to fit on screen, and the data
resolution. You need to keep track of the real resolution of the data,
and how much of it you are seeing on screen, before you make hasty
decisions about quality. Many data sets have many times more data
than will fit on screen.
-
Copy to
clipboard to export a map. If this is not on the toolbar, use the
right click
popup menu, or the File menu. You have
the choice of a quick export, or a cartographically pretty map with a
Grid/graticule.
You want just the map in your reports,
and not the window.
-
Map zooming. For large maps,
consider
Subset
(graphical) & zoom instead of blowing up so you do
not wind up with unusable large maps.
- To open the
OpenStreetMap (OSM) data, use the menu choice Database,
Load OSM overlay, and select the directory. This will open a series of
databases, and use intelligent display options in terms of symbolization
and what shows on the map. If you open as regular databases, you
may have to play with the display options, and it might be slow to draw
and then completely cover the map.
-
Database to overlay the TIGER, and
gazetteer. The program will recognize the TIGER as an important
standard data set, and use appropriate symbolization (which you can
modify if desired). This is different than the
Open database without map DB button on the main
toolbar, which just opens a database for analysis without map
interactions. Table display
options, in particular:
- Filter: restrict display
to only records that meet specified criteria. You will need to
use the wildcard symbol ("*" for MICRODEM's database,
but can be different in other programs).
- Plot: plot
selected records on the map. You can control the
symbolization. The best choices will be: Color code by
database field, or Icons
- Stats:
perform statistical operations (not map based) on the database.
- ID: identify records on associated
map by double clicking. Same function as ID button on
map
toolbar.
- Map query:
Geographically filters data; restriction will remain in effect until removed.
You will most often use a rectangular box.
- Frequency table which you can sort from most to least common.
- To get gazetteer schools and churches:
- This will require a three part filter: for the type of structure,
for the state, and the county. (Even though this database is for
Maryland, it has some records listed for other states, since each
feature, even the Potomac River which passes through multiple states and
DC, is listed for a single point in one of the states).
- If you export this database subset,
Report button for the
database
table form, then DBF file, it will give you the greatest flexibility and
require minimal disk space. GIS work usually involves creating a
numbe of new data sets, and you have to balance creating them on the fly
as needed, or saving them after first creation, and being able to find
them (GIS Project
Management).
- To find Eastport Elementary School (or another feature):
Table of contents to control display of databases on
the map, to change the plot order, and to plot/hide layers.
New Landcover map (NLCD). You want the TIF file; if
you do not see the extensions, tell Windows to
show file extensions. This is an image, which is
fundamentally different from a DEM and has different display options and
characteristics, and different choices in the menus.
Grid: How is this map's grid and
graticule different
from the DEMs?
LIDAR Point clouds on the map toolbar for
the one-ninth second NED DEM.
- Turn the NED display to a grayscale reflectance map.
- Pick the directory with the LAS files. The 2011 data set
covers a larger area and should be your choice.
- Insure the display is set to elevation, and adjust the range to 0-30
m. Then display the points on the map.
-
Subset
(graphical) & zoom to an interesting building or
group of buildings.
- Look at that small subset
OpenLG view controls.
Bancroft Hall, the swing bridge over Weems Creek, or the State House are
good examples.
You will need to use the following additional techniques:
Legends:
- For the DEM map, you can put a legend on with the
Legends/marginalia option by
right clicking. You
can pick where to put it, which should not be in the same
location as the scalebar.
- All of these maps should have a scalebar with the
Legends/marginalia option by
right clicking.
- For the database, there are several options:
- Legends/marginalia
option by right clicking
will work if the plot is of a numeric field.
- For Color code by DB field,
you can get a legend, which will frequently
appear in a separate window because it can be
very large. You can copy that to the
clipboard, and either put it beside your map
inside Paint or
paste it onto the map (right click,
paste from clipboard lets you drag to whatever
region of the map does not have any important
content) . This will always be the case for a
string field.
These icons should be extracted and stored in
c:\mapadata\icons, as a GIF or PNG file.
GIF format will probably be better to make the white
background transparent. If the "Right click" and save as option does not work, try to copy to
clipboard and paste in Paint and then copy, use the snip tool, or
make your own version in Paint.


KML and Google Earth
- KML
database export for Google earth. For this lab you can make a quick export (or
multiple exports with different filters) from the
Report button for the
database
table form. This provides some of the functionality of the database.
To get the icons you might need to use the deliberate export. The
deliberate output provides a lot of flexibility to customize the export.
- KML export map image. This
creates a "dumb picture", but it will be in the correct location.
- Clean up KML exports and save KML/KMZ within Google Earth.
This will make the results much more usable, which is your job when
you make a map.
Verify what is at a location:
- WMS Maps. This must be a fairly
small area in the US, but you can get color aerial imagery. You must
pick the state you want.
- Right click,
Export,
- KML export, which will place the map on Google Earth, and let you see
the Google imagery.
- Location to Google Maps
- USGS data, TNM viewer: gets USGS color imagery
Suggestions added 8/26:
You are not expected to make your first maps perfect; the goals of this lab
are given above, and we are learning by doing. Hopefully with each lab the
process will get easier, and your maps will get better. If you would like
to improve your maps, try the following:
- The missing data, holes, or voids in the NED are very annoying.
You could try the following:
- Edit, DEM Holes, Missing data to sea level.
This will not work in every case (when you are not near sea level), but does here. After you do
this, you can File,
Save DEM, "Entire DEM, MD DEM".
Then open the new DEM in the future.
- Go to Options,
Import/Export, and pick
Missing Values to sea level. This will not work in every case, but
does here.You do not need to save the DEM, since this will happen every
time you load the DEM.
- TIGER. There is an option on the
Manage Overlays choice to add the
TIGER data. This requires that you place the data in the correct
location, and index it. For now, unless you want to deal with a number
of details, just open with the database button.
Load project (after you have
saved it with File,
Save Project) will let you restore most of your work. There are a
number of caveats to making this work, and it will generally not save you
much work.
Last revision
8/20/2018