SAMP Mapper Tutorial  |
| Provplan > Metro Bay SAMP Mapper > Tutorial |
| Table
of Contents: Key
Mapper Concepts
We map the location of each parcel and identify which attributes belong to which. This is the foundation of GIS. A GIS tells us where something is and what it is. Computers are synonymous with GIS, and using a computer we can have hundreds of fields (different attributes) for thousands of records (parcels). You will be able to examine the attributes of features as you navigate Geographic Data Viewer maps. Concept #
2: Information is separated into layers. A map represents
the landscape in an artificial way. Vector layers represent
features in one of several ways:
You might hear people talk about coverages, themes, or shapefiles. All these terms are other names for layers of information. With individual
layers we can conduct analysis between layers and only display
layers of interest. As you are work
with Geographic Data Viewer maps you will be able to turn different
layers on and off as you desire. We suggest using this link to open an actual Mapper window. This way, as you go through the tutorial you can practice what is being explained.
-------------------------------------------------------------------------------- Navigating Around Maps
First, select one of them, go somewhere on the map and press the left mouse button. If it is the Zoom In tool the map zooms in. The center of the new map is wherever on the map you clicked the mouse button. The Zoom Out tool zooms out the same way. Second, you can zoom in more precisely by pressing the mouse button somewhere on the map, holding it down, and dragging a box. When you let go of the mouse button the new map extent will be the area defined by the box. When zooming out, the area defined by the box becomes the new map extent. Note: On The Mapper, a maximum and minimum scale may be set. A maximum scale is set so you can't zoom in further than the data is designed to be used at. A minimum scale is so that people don't zoom out beyond where there is information. As well, some layers or labels for layers may only appear at certain scales. This is to improve the speed of the maps and to prevent them from getting cluttered at different scales. There are a few other handy buttons that will make life easier:
-------------------------------------------------------------------------------- Turning Layers On and Off and Making a Layer Active Hopefully you've had a chance to take a look at the introduction to GIS Concepts section where we discussed layers.
After you
turn a layer on or off, the map will automatically refresh. If
you want to turn off this function, uncheck the By default, some layers may be turned on and others may be turned off when you initially open the map. In our example
above, you can see that only the "SLOSH Storm Surge" layer is turned on
(checked box). You can also see that it is 'Active' (radio button
selected This means that
the spotlight is on this layer. In other words, this is our way
of telling the computer that this is the layer we are interested
in. You can only perform an action on the active layer. The different actions are described below. Querying Attribute Information for the Active Layer The introduction to GIS Concepts section discussed layers and how features have attributes in a GIS. Suppose you are interested in who owns properties in a particular area. First, you ensure that the layer with property attributes is the active layer (see the above lesson to do this). In this case, 'Parcels' is made active. The
Identify Tool
-------------------------------------------------------------------------------- Display or Remove an Inset Map
If it isn't
useful, you can easily switch it off. Just press the Overview
On/Off button -------------------------------------------------------------------------------- Press the Create
URL button -------------------------------------------------------------------------------- To print a map,
press the Print button
Simply print it as you would any other page on your computer, but make sure you set it to print landscape (sideways). The required steps depend on your printer, but they should be fairly straightforward. Once you have printed the map, close the window and you'll be back to the Geographic Data Viewer interactive map. -------------------------------------------------------------------------------- Perhaps you
are looking at the Narragansett Landing Redevelopment Plan, and
want to measure the length of Public Street west of Eddy Street
that will recieve street tree plantings. This is just one example
of many possible applications for the Measure Distance tool. -------------------------------------------------------------------------------- Selecting Features with Attribute Queries You can select
records using a logical expression called a query
which selects records based on certain attribute criteria. The
Query button -------------------------------------------------------------------------------- You can also select specific spatial features and look at their attributes. This is essentially asking, What are the attributes of these specific features? To do this, you select the layer of interest and then pick how you want to select the features. First, you can
draw a selection rectangle using the Select
by Rectangle tool -------------------------------------------------------------------------------- Highlighting features within a specified distance using the buffer The buffer enables you to highlight features from a particular layer (i.e. schools, libraries, hospitals, parcels) within a specified distance from a selected feature . The resulting buffer zone is displayed on the map and attributes of all highlighted features are listed in the table below the map. Here's how to create a buffer zone. First, select a point of interest. If a specific parcel address is not known, manually zoom in on a specific area of the map. Zooming in may have to be repeated if the area selected is too large and individual parcels are not visible. For this example, make the "Parcels" and "Land Use" layers visible. Make "Land Use" the active layer. Select a parcel
using the select by rectangle tool
Click on the
Buffer tool
That's it for the tutorial. Have fun mapping! |
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You can move around the map using the Pan
Tool. The Pan tool lets you slide around to different
parts of the map. Suppose you want to go north (up the map). Grab
the Pan tool and grab (press and hold down the mouse button) onto
the map and pull it down. Whatever part of the map you grab with
the little hand will end up where you let go of the mouse button.This
works for moving any direction on the map.
The
Zoom Tools are unique to digital
maps. They are very much like using an actual magnifying glass,
as the icons imply. The
tool with the little plus sign lets you 'zoom in', while the one
with the little minus sign lets you 'zoom out'. There
are a couple of ways to use these tools. 
Another button is the Zoom to Full Extent
Tool. It zooms you out
to the maximum extent of the information.
The Zoom to Layer Extent Tool
zooms to the maximum extent of the active layer. Next, you will
find out how to make a layer active.
The first is the Previous Extent Tool.
This button jumps back to the previous map extent you were at.
If you want to go back to where you were three zooms or pans ago,
press it three times. 
box. When the auto refresh function is turned off, you'll have
to press the
button every time
you update the map. 
). 
allows you to get attribute information about a feature by clicking
on it. You select the Identify tool to click on the feature whose
attributes you want to examine. 
.
on the toolbar to create a URL that can be pasted in a browser
address bar to recreate the current map. This URL will preserve
the viewscale of the map as well as the layers displayed, so be
sure your map is the way you would like it before creating or
sharing a URL. Clicking the tool will open the yellow URL panel
seen below. Then, simply copy the link and paste into an email
or browser. 
on the toolbar.
.
Select the tool, click on the start location (A) and then click
on the end location (B). As you move the cursor, you can see how
far the pointer is from the start location in the Segment length
box. The distance between the two points is given: 944.2 feet.
to reset the units of measurement.
!
The Clear Selection tool clears/unselects
any selected features, distance measurement lines, etc. This tool
is the equivalent of a few good shakes of an etch-a-sketch. Unless
you want to print a map with features selected (they usually appear
shaded yellow) it is a good idea to hit this button before you
create a print page.
opens the query panel seen below. This is essentially asking,
Where are the features that have these specific attributes?
.
Every feature touched by the rectangle is selected and the associated
attributes display as a table.
.
Fill in the buffer field with the features
that you would like to be highlighted (i.e. 'Parcels') and the
distance of the radius of
the desired buffer zone (i.e. 900 ft). Your
features field cannot be the same as your
active layer; this is why in this example we selected our schools
from the 'Land Use' layer.
