Projections: Square Mileage of Florida Counties

-

 

Projections Map


This map layout is a perfect example as to why understanding projections in GIS and coordinate systems is extremely important. Depending on the coordinate system your map is defined at, and the projection used for your data, it can determine major differences in mensuration. This map shows an example of calculating square miles per county with different projections for the state of Florida. The table displayed shows varying square mileage per county depending on the projection the data is in. Data can also look rotated or shifted as it is drawn if the data has a source spatial reference of a certain projection, and the map is not displaying that projection. It is a good idea to have your data mapped to the same projection that your map is referencing. This will also allow you to share the map as a web map to your Arc GIS Online account. The 4 selected counties are depicted in color, and the three projections used are displayed in the 3 different views above. 

Comments

Post a Comment

Popular posts from this blog

TIN's vs. DEM's: 3D Elevation Models In Arc GIS Pro

-
Image
 Elevation Models For GIS Today we are going to run through some analysis of comparing Digital Elevation Models (DEM's) to Triangular Irregular Networks (TIN's) using Arc GIS Pro.   One of the main differences between TIN's and DEM's, is that a DEM file is raster based, whereas a TIN elevation model is vector based. In GIS, we can use TIN's and DEM's to analyze elevation of local areas or global even to conduct slope analysis, aspect ratio, terrain mapping, and solve complex problems.  Using a DEM to Develop a Ski Run Suitability Map In the example below, we are identifying where an engineering firm would place a ski run for a resort in an area based on elevation, slope, and aspect parameters. We used the weighted overlay tool to combine 3 reclassified rasters of elevation at a high altitude, slope at a high pitch, and aspect for a SW positioning with given percentages of weight.   25% aspect  40% elevation  35% slope This was our result: As you can see, we c...
Read more

Isarithmic Mapping: Annual Rainfall in Washington

-
Image
  Isarithmic Mapping Today we are going to talk about Isarithmic Mapping! This type of mapping is a way to explain smooth or continuous phenomenon such as a heat map, weather, temperature or rainfall.  There are two types of these kind of maps, Isopleth and Isometric . .. Isopleth Maps : These are made from perceptual poi nt data such as the population of an area or the rate of crime in an area. These maps should be normalized if using raw data and should come from averages, densities, and ways to standardize the data. Such as the number of Covid cases per every 10,000 people, rather than coloring polygons of counties based on the number of covid cases.  Isometric Maps : These come from true point data, such as crime locations as points at a certain address or X and Y coordinate The two rainfall maps of Washington below are Isopleth maps as they are using perceptual data of areas regarding their average rainfall in the state of Washington. This data is already standardi...
Read more

Ward 7 Public Schools in Washington D.C.

-
Image
  Hello everyone! Today I decided to experiment with a completely new color scheme for my mapping lab assignment.   I went with purple!   I am not sure why, but it just seemed right at the time... The map above is unique as today we are going to focus on our main talking points staying within the realm of Cartography. In particular, we are going to talk about Visual Hierarchy, and the map making process following Gestalt's Principles. As a GIS analyst, we must look at making maps and visuals as a graphic design process as well as a scientific process. This means that maps need to have a theme, a feel, and most importantly provide context to the map reader in a way that makes sense.  Before we dive into the map above, lets explain what visual hierarchy is and the Gestalt Principles! Gestalt's Theory is as humans, we see or perceive the whole of something before we actually make out the individual parts. When you see a landscape, you see the landscape first, then the ...
Read more