Module 10 - Cartography - Flow Line Mapping

Flow Line Map:  Immigration into the United States
Percentage of Total Immigrants per State

This week we got a lot of valuable practice in Adobe Illustrator as we constructed flow lines using the pen tool.  We also learned the principles of constructing proportionally-sized lines based on the values they represent.  In order for the lines to be reasonably similar in width (rather than gigantic vs. almost invisible), we can base their proportional widths on the square roots of the actual values, because the immigration values themselves cover a very large range.

It is important for this type of map a to have a strong figure-ground relationship so that the flow lines are emphasized.

Week 11 -GIS - Vector Analysis II

A map created using buffering and overlay tools in ArcGIS

This week in Intro to GIS, we learned about using various tools for vector analysis.  The goal of the exercise was to identify the zones in which campsites might be built in the area of interest in the De Soto National Forest, Mississippi.  The criteria are that the campsites must lie within certain distances of both roads and water bodies, and must not overlap the conservation areas, in which plants and animals are protected.

To identify the zones that are a certain distance from the roads and water bodies, we use the Buffering tool in ArcMap.  Buffering involves drawing a line a specific distance from a point, line or another polygon. The area inside the line forms a new polygonal feature which is the buffer. In the case of this map, the buffers surround lakes, rivers and roads at a distance of 150, 500 and 300 meters respectively.  We want the campsites to lie within the buffers:  they should be close to both roads and water bodies.

Use of the union tool combines all of the features of two or more layers, while the intersect tool combines only those features that are common to both layers: that is, their intersection.
In this case, we used the intersect tool to identify the areas on the map that are within the buffers of both the roads and water layers: in other words, the areas that are within minimum specified distances of both roads and water features, as given by the buffer operations described above.

Once this intersection layer was isolated, we performed one more operation with the Erase tool:  it excludes the features (or area covered) of a third layer, namely the Conservation Area layer, from the layer created by the intersection of the water and road buffer.  We do not want the campsites to lie within these areas (shown in light green above).

The final result gives us possible sites for campsites, and shown in pink above.

Module 9 - Cartography - Isarithmic Mapping

Isarithmic Map:  Continuous Tones

This week's exercise in Introduction to Cartography involved generating maps with Isarithmic data symbolization.  This precipitation data for the State of Washington is of smooth and continuous nature over the whole area.  Measurements are taken at control points, then the data is interpolated to form contours, or lines of equal value.  A color scheme can be used to further clarify the data.







In the first map, the values in inches of participation are continuous, or non-classed. This method is precise because it represents very fine divisions by many slightly different hues.
 In the second map, ranges of precipitation have been divided into classes, and the representative colors are more distinct from one another.  It is not as precise, but it is easier to evaluate in a general way.
Contouring is yet another isarithmic method to represent changes in values over an area, and it has the advantage of being easily replicated in black ink only.

Isarithmic Map: Hypsometric Tints and Contours

Isarithmic maps are useful in many natural resources applications such as petroleum exploration, hydrology and mining because they are ideal for depicting elevation, depth, thickness, chemistry, and many other physical properties typically examined in the evaluation of natural resources.

Module 8 - Cartography - Proportional Symbol Mapping

In this week's lesson, we made maps using proportionally-sized symbols to represent different values.  The first map displays wine consumption in thousands of liters for European countries (obtained from The Wine Institute).  We imported a simple image of a wine bottle in .png format, and used it in the symbology instead of different sizes of circles or squares.  This adds some interest to the map and immediately tells the viewer what it's about.
This map was done entirely in ArcMap.



The second may was started in ArcMap, and most of the work was done in Adobe Illustrator.  It concentrates on wine consumption in western European countries, using the same data that was used in the first map. We imported the same wine bottle image, and combined it with a circle into a single symbol using Illustrator.  In this case, the symbols are still proportional to wine consumption in each country, but we've shown the values next to the symbols, since there are only seven.  Again, using the proportinally-sized symbols, and the wine bottle symbology, is a very effective way to convey the data to the map viewer.

Weeks 7-8 -GIS - Data Search

This map is a combination of elevation data (DEMs) and surface water
data and also shows a DOQQ centered on Saint Petersburg, the largest
city in Pinellas County.

During Weeks 7 and 8 we had lots of practice in searching for data, reprojecting the data and assembling into our own map designs for a particular county, in this case, Pinellas County.  To this set of maps I added vector data for county boundaries (for Florida and for Pinellas County), cities and towns, major roads, public lands, hydrography, land cover, and invasive plant occurrences, as well as Digital Elevation Model and Digital Orthgraphic quarter-quad raster images.  My sources were the USGS National Map website, and the Florida Geographic Data Library website.

This last two weeks was a lot of work, but I am impressed with the fact that I'm gaining the tools that will make it possible to go out and find the data I need and put it onto a map (for anywhere in the United States at least).

This map displays land cover data from a USGS raster file.
For reference, cities and towns and major roads are also shown.

This map compares sites of invasive plant species occurrences
with locations of public parks and recreational areas,
major roads, and public and private lands identified
by the Florida Natural Areas Inventory  as
Florida Conservation Lands for Pinellas County, Florida.