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2. Maps


About Geiger Bot's Mapping

By default, Geiger Bot's map display is optimized for speed.  It uses the fastest base map possible (satellite) which is not the ideal base map for finding a location or data visualization.

Geiger Bot's mapping is somewhat unique in that it is not a static display of pre-rendered data, but rather, displayed according to the parameters you choose.  By setting the colors (LUT), base map, radiological data layer, alpha blending, etc you can fully control how you want the map to look.  In this way, it is a small, self-contained GIS server -- though a very specialized and limited one.

Manually controlling the min/max of the map scale, and changing the LUT allows you to fine-tune the contrast to better visualize the differences in a specific set of data.

Configuring the base map, alpha blending, and level of detail can optimize between showing where the data is, and showing what the data is.

Mapping is designed primarily to be interactive.  Almost all mapping options are on the map interface itself.  The intent of all of this is to give you options for exploring the data and best visualizing it.

A Japan Times writer called it "strangely addictive".

Mapping - Scale Control:

Changing the Map Scale
You can change or reset the map scale using swipe gestures.

These commands are also available at the bottom of the "LUT" menu directly.

Much like the dynamic range of a digital camera, this is always a tradeoff between contrast and range.  The default settings are sort of analogous to metering for indoor lighting; anything beyond that will be a blown highlight.

 Position Direction Fingers Effect
 Top Half
 ↑ Up
 1 Max+
 Top Half
 ↓ Down
 1 Max-
 Bottom Half
 ↑ Up
 1 Min+
 Bottom Half
 ↓ Down
 1 Min-
 Any ← Left
 1 Reset Scale
 Any ← Left
 2 Toggle Scale Mode

Increasing or decreasing the max/min is accomplished by swiping up or down.  Whether you swipe on the top or bottom half of the bar determines whether you affect the maximum or minimum.

While holding your finger down, you can move it up or down freely to change the scale value to a precise amount.  Only when you lift your finger will the scale will be applied.  This allows for much finer control than mere flicking.

Swiping left with a single finger will reset the scale to default values.

Swiping left with two fingers will toggle between natural logarithm or linear scaling.  Using a natural logarithm allows for a greater range of values to be displayed while still maintaining contrast for lower ranges. 

(NOTE: Safecast LUTs have fixed scales and cannot be changed.)

  • NOTE: The mapping module can be entirely deactivated as a failsafe if you experience any issues.
    • Settings -> Log File -> Disable Map
    • After changing this setting, you must force quit and restart the app (or restart your device).  (you can also change the setting in Apple's main on the home screen)
    • To force quit: 
      • Press home.
      • Double-tap home so that the multitasking bar appears at the bottom of the screen.
      • Hold down on the Geiger Bot icon until a red "-" appears in the corner.
      • Tap the "-".
    • Notes about Disabling Mapping
      • When mapping is disabled, data will not be logged to the mapping database
      • To re-enable mapping, you must restart the app as described above

  • Custom Map Layers (1.6.3+)
    • All preconfigured map layers are actually combinations of multiple individual data sources, with a few exceptions.
    • You can create custom map layers with the same flexibility and same options.  The combinations aren't infinite, but probably multiply out to a relatively large number.
      • Example: The "Safecast" layer is a combination of:
        • Primary Layer: Safecast data uSv/h
          • Preprocessing effects: Smart Resize 3x3
          • Postprocessing effects: Halo
        • Sublayer 1: Safecast EBK interpolation uSv/h
          • Raster math: Overlay
          • Alpha: 50%
        • Sublayer 2: USGS/GSC NURE uSv/h
          • Raster math: Overlay
          • Alpha: 50%
        • Sublayer 3: Geoscience Australia uSv/h
          • Raster math: Overlay
          • Alpha: 50%
    • A custom map layer allows you to define your own combinations of any data source or combination of data sources.  This is currently limited to a primary layer and 3 sublayers.
    • You must enable this in Settings -> Map before it will be displayed on the "Layers" list

  • Mapping currently displays data from:
    • A local database of your recorded data
      • Similarities to log file
        • Recorded at the same time
        • Use the same log time interval
      • Differences from log file
        • Requires GPS coordinates -- you must first enable GPS on the settings screen
        • Not cleared out by a "reset"
      • Your data is always displayed on top of all read-only databases listed below
    • Safecast Dose Rates 
      • A large collection of frequently updated ground vehicle surveys
      • Global coverage, but most data is focused on Japan due to Fukushima
      • The Safecast layer can now be updated on demand in-app!
      • (updatable) (data global; Japan primary)
    • Safecast Historical Dose Rates
      • For historical perspective, both the data and interpolation layers for Safecast generated on 2013-04-15 are included.
      • These can be used in custom layers to see differences over time, and new areas surveyed.
      • (read only) (data global; Japan primary)
    • US DOE / NNSA AMS Fukushima Response Surveys
      • Aerial and ground vehicle surveys of Japan from 2011 of fission product release from Fukushima
      • Including Cs-134 and Cs-137 activity, corrected for decay to date of you viewing the map
        • A simple decay rate calculation alone does not account for environmental dispersion.  In reality measured levels of these isotopes will be lower as they have not remained in a fixed position since the surveys in 2011.
      • (read-only) (data Japan only)
    • US EPA Uranium Mines
      • A database assembled by the US EPA from federal, state and local sources of uranium mines and claims in the US
      • (read-only) (data US only)
    • USGS/GSC NURE Dose Rates
      • Aerial gamma radiation surveys of North America from the 1970s and 1980s, showing natural background radiation.
      • NURE was actually a program begun in the 1970s under the US AEC (Atomic Energy Commission).  It was later transfered to the DOE which assumed the AEC's functions, and then later maintained and processed by the USGS. (the original records were on tape and microfilm)
      • This data is a further update of the original NURE data and contains a number of Canadian studies from the Geological Survey of Canada
      • This dose rate is a combination of both the terrestrial and cosmic ray dose rates.  It is an approximation, as natural background rates will vary over time.  Note the cosmic ray dose rate does not include neutron radiation.
        • While the original data was not intended to show manmade activity, examples can be found.  Consider Gunnar Mine in Saskatchewan, Canada.  If you zoom in you will see a statistically significant elevation in the dose rate, presumably from mining tailings.  While there is no singular hotspot, due to the natural high grade of the ore once mined there, it remains elevated over a large area.  The mine itself was closed down in the 1960s, before the surveys were performed. (The ore was sold to the US.  Nearby Uranium City lasted into the 1980s, holding out hope for another boom due to the oil crisis, but by then the demand and price for uranium had dropped sharply, and the world had moved on.)
      • (read-only) (data US/Canada only)
    • AIST Japan Natural Background
      • Similar to the NURE dose rate dataset, this is an approximation of natural background radiation, as a combination of terrestrial and cosmic dose rates
      • The terrestrial data was derived from AIST mineral sample data (~3k points) using Empirical Bayesian Kriging in ArcGIS 10.1 and clipped to Japan's administrative boundaries.
      • The cosmic dose rate was derived from a NGA DTED0 DEM product and added to the terrestrial dose rate.
      • (read-only) (data Japan only)
    • USGS Uranium Concentrations
      • This is a somewhat less complete (Canada omitted) and lower resolution version of the above NURE data, for uranium concentrations, in ppm.
      • Naturally, there is quite a bit of correlation between uranium mines and uranium concentrations.
      • This is the only layer that the default LUT scale does not work well for.  I recommend changing it to linear scaling, range 0.03 - 10.0.
      • (read-only) (data US only)
    • NOAA Global Radiance
      • This is the "Earth at Night" or "Night Lights" dataset.
      • It is *not* radiological data.  It shows human-created light sources captured with satellite imagery.
      • In industrialized nations, it correlates with population density.
      • Data has been rescaled to 0 - 10 (arbitrary).
      • (read-only) (global)

Mapping Controls - Bottom Toolbar
  • [LUT]
    • Change LUT
      • Changes the false-color palette lookup table (LUT) that is coloring the data points
      • These are used to enhance contrast to the human eye, as it is usually easier for the human visual system to discriminate between color and brightness, than brightness alone.
      • The color is *NOT* an indication of frequency (energy / wavelength) of radiation.  Merely the intensity (dose rate / count rate).
    • LUT Options
      • Scale type: (Linear | LN | LOG10)
        • LN and LOG10 scaling use logarithms to emphasize differences in the lower range of values more.  This is similar to gamma correction.
        • Like gamma correction, the cost is decreased contrast in the upper range.
        • Changing the scale type also sets the corresponding default range
        • It is a faster alternative to the rather imperfect 3-finger swipe gesture
      • Range: (0.03 - 1.0  |  0.0 - 1.72  |  0.03 - 65.54)
        • This is selected when changing the scale type, but can also be selected manually directly
        • For precise control over the range, swipe on the LUT control directly
      • Invert:  (ON | OFF)
        • This reverses the order of the LUT
      • Discretize:  (4 | 8 | 16 | 32 | OFF)
        • Discretize significantly reduces the color depth of a LUT
        • This is usually done to provide more distinct classification "steps" on a map and be simpler to look at
  • [Layer]
    • Change Layer
      • This allows you to select a collection of data layers
      • User points and EPA Uranium mine point features can be turned on/off independantly of data layers at the bottom
      • This also includes the "Update Safecast Data" command

  • [Menu Icon]
    • Show Top Toolbar
      • Show/hide the top toolbar and on-screen controls
      • This also shows or hides the "HUD", a reticle (crosshair) in the center of the screen that will display the data value of a pixel from any of the data tile layers
      • These provide additional settings that are changed less frequently
  • [Window Resize Arrows]
    • Zoom To Fullscreen View
      • Toggle full-screen or windowed view
      • Windowed mode tracks your position.  Full-screen mode does not.
        • When you switch back to windowed mode, the map will "snap" back to your current position.

Mapping Controls - Top Toolbar

  • [-] [SD] [HD] [+] [++]
    • Level of Detail
      • Resolution
        • This controls the resolution of the data displayed
        • For data tiles, "++" is native 1:1 resolution.
        • Each LOD displays roughly 4x the data of the previous LOD
        • Data/map tiles are 256x256 pixels.
      • Apple Maps notes: 
        • Using a lower LOD for data tiles generally will not increase performance.
        • The purpose of the LOD control with Apple Maps is to make the data easier to see.
      • Google Maps notes: (1.7.0+)
        • "Points"
          • Annotation point features are not supported in Google Maps at this time
          • The data can be rendered via a tile interface, however.
          • Thus the "User point size" and types listed below do not apply to Google Maps.
        • Performance
          • Google Maps uses more CPU resources than Apple Maps
          • It also provides a free 2x tile resize on the GPU
          • All LOD settings other than native 1:1 resolution (++) exploit this free 2x resize with Google Maps
          • It is therefore recommended to use the LOD setting of "+" with Google Maps
            • Performance: 4x faster
            • Visual difference:  Very little on a retina display
      •  NameUser Point
        Size (px) *
        Database Tile Size
        User Point
        Type *
         16x16 GridFastest for displaying user points (Apple Maps only)
         SD16x16 32x32 Grid
         64x64 GridFastest for displaying data tiles (Google Maps)
         128x128 GridRecommended setting for Google Maps
         256x256 CircleFastest for displaying data tiles (Apple Maps)
        *1.7.0+ User point size only affects Apple Maps at this time.
  • []
    • Point Mode
      • Default display mode.  Points are drawn as false-colored circles.
      • This provides a higher resolution of "user points" than showing the full label
  • [1.23]
    • Numeric Mode (Apple Maps Only)
      • Numeric Mode only works with user points and EPA uranium mines
      • It display of the dose equivalent rate and date of measurement (or a mine name, and the number of mines in that rectangle)
      • It has a fixed level of detail such that the labels do not overlap.
      • If the dose equivalent rate displayed is an average, the number of points included in the average is shown in parenthesis after the dose rate.
      • The date of the point, or for an average, the most recent point in the group is shown on the 2nd line.
      • Format:
        • x.xx uSv/h (n)
        • yyyy-mm-dd
  • [Map] 
    • This selects from a number of alternate base map tiles
    • Note these will all load slower than the standard map types, to varying degrees
    • These tiles are displayed on top of the standard Apple base map.  It cannot be disabled.  Thus, your bandwidth use can potentially double.
      • Standard (Apple) Map Types
        • Road
        • Satellite
        • Hybrid
        • Comments:
          • In iOS 6, the road/hybrid overlays and labels currently have a speed penalty, both in loading speed and while panning the map around.  I believe this is because the "label" layer is no longer a raster but vector-based.
          • For the absolute best performance, the Apple "satellite" layer is recommended.
      • Stamen
        • Toner
        • Toner Background
        • Toner Lite
        • Watercolor
        • Terrain (US only)
        • Comments:
          • Stamen "toner" tiles add exceptional contrast for data visualization, but can load slowly
          • Were it not for the speed they would be the default in Geiger Bot
          • The Stamen Terrain map is US only, and will not display if you are zoomed out all the way
          • The inverted variants are produced from inverting the colors of the image tile being displayed, and are not standard Stamen imagery products.
          • Suggested types:
            • Toner lite (inverted) at 100% map alpha
            • Toner background (inverted) at 20% map alpha
      • OpenCycleMap
        • OpenCycleMap
          • This primarily highlights bicycling routes
        • Transport
          • This shows mass transit routes such as subways
        • Terrain
      • MapQuest
        • MapQuest
      • OpenStreetMap

Mapping Controls - On-Screen

  • Map alpha
    • Changes the brightness of the map.  Different map types have different perceived brightness.
    • Default is 100%
    • Setting map alpha to 0% renders the tiles without a basemap (1.7.0+, iOS 7+)
    • Using a map alpha other than 100% or 0% will use somewhat more memory as the "blank" tiles used to create the effect still occupy memory (iOS7+)
  • Point alpha
    • Changes the transparency and brightness of the points
    • Default is 100% (ie, not transparent at all).
    • Individual layers can have transparency set differently in a layer collection.  This is a "master switch".

Map Reference: Performance

  • Generally, mapping is now quite fast and efficient.
  • The main factors which have a negative impact on performance are:
    • 1.  Using a "vector" basemap with geometry features.  (Standard/Hybrid for Apple and Google Maps)
    • 2.  I/O read speed from disk
    • 3.  Apple Maps: Showing user data points and/or EPA uranium mines
Map Reference: Data Caching and Offline Use
  • 3rd Party Base Map Tile Caching
    • 3rd party tiles can be cached to work offline, with a persistent cache of any limit you set. (1.7.0+)
  • Apple Map Tile Caching
    • Apple Map tiles are cached by the system automatically using an entirely different method I do not control or know the details of
    • The Apple map tiles DO work offline -- especially in iOS6
      • iOS6 also uses vector (polygon) map data with Apple tiles.
      • This vector data is downloaded fairly aggressively and enables extended use relative to iOS5 when losing connectivity
      • However, this is designed to continue working during brief service interruptions, and is not a true offline mode
  • Geiger Bot Data Layers
    • All data layers are stored locally.  They will work online, or offline.
    • Up to 2MB of RAM will be allocated to cache data tiles, depending upon free memory.  This will significant improve speed when the map is zoomed.
      • However, in low memory conditions, it is possible no cache can be allocated at all.
      • Thus, if you notice loading tiles while zoomed in is taking an usually long time, try quitting some background apps and reloading the layer (by changing the layer or LUT) which will attempt to re-allocate the caches

For more information on mapping, including a comparison of available LUTs, please see the reference information towards the bottom of this document.