Samana Cay BF - Columbus' First New World Landfall?

    Samana Cay - Landsat ETM+ Image N-18-20_2000(1:85,000)     Samana Cay - EVS Precision Map (1-85,000)   My interest in Samana Cay was the result of a serendipitous moment.  A few evenings ago while editing my Islands of the World point file, I became curious about the Turks and Caicos Islands.  Using my GSHHS World Shoreline map, I located the Turks and Caicos Islands.  Not an area I have done much mapping in, but interesting.  To the northwest was a small island off by itself, Samana Cay.  Nothing particularly outstanding, just a nice little island facing the Atlantic Ocean.  Curious soul that I am, I checked out the Wikipedia article and Wow!  Some scholars think this might be the site of Christopher Columbus' first landfall in the New World.  Pretty cool.

I identified the Landsat ETM+ mosaic, loaded it into Global Mapper and began mapping.  The completed map is nice.  The Landsat image is pretty cloudy.  More research and my next Wow!  Samana Cay is the largest uninhabited island in the Bahamas.  An uninhabited island close to home (USA).  How cool.

All of you Florida readers hunting for your Crusoe Getaway, Samana Cay could be your island.  People from Acklins Island visit periodically to collect cascarilla bark.  Other than the occasional Acklins Island visitors, you could be all alone contemplating whatever it is you want to contemplate.

Enjoy!

Thoughts - Quantum GIS, Africa and 6th Graders, A Recipe for Mapping Success.

If you have followed my posts you know that I do most of my mapping work in Global Mapper, a solid mapping program that is easy to use and handles very large format image files with ease (Landsat, SRTM, GeoTIFF). However, it costs real dollars. Big bucks for me and unaffordable bucks to outfit each student workstation with a mapping package.  I have spent the last year learning how to make maps using Quantum GIS (QGIS), a well-maintained and powerful open-source mapping package.

I teach middle school students between the ages of 11 to 14, social studies which includes world history, US history and geography. We spend a good deal of time working with open-source software (OpenOffice, Irfanview, Audacity, etc.) to learn about our world and how to make effective use of technology in the classroom. I have always wanted to bring mapping into the classroom. This year I decided to give QGIS a try with my students. I was determined to teach my students how to identify and display spatial data on a map. That brings me to the West Africa map and QGIS..

This year all of my students are learning to make maps. They have learned the difference between vector files and raster images. They are becoming adept at labeling countries, cities, empires and city-states. They love to use all the wrong colors and fonts, but I let them because they are having fun making maps.  So far the projects have been relatively simple, but challenging in a mapping sort of way.

Today, my 6th graders (11-years old) were identifying and labeling countries in Africa using QGIS and a variety of vector files and a large format raster image of Africa taken from the Natural Earth website. They finished the country identification phase of the mapping project and wondered what to do next. I said, "Make a capital city point file and identify and label African country's capital cities."  In the past, I would have labored long and hard to teach them how to make and use a point file. We would have spent a great deal of time setting up the symbology and label parameters.  However, today within minutes all of the students created their capital city point file, defined parameters and were busy plotting capital cities. How cool is that!

Enjoy! I know I sure am!

Thoughts - They Aren't as Good as EVS Precision and That's the Fact , Jack!

Olimarao Atoll Locator Map

You all remember my last post, Olimarao Atoll? I spent a few days prior to posting it doing research into available online mapping. I checked out the standard mapping packages for Olimarao Atoll vicinity maps. Check out my results below...

Olimarao Atoll - Vicinity Map from Google Maps - Some land polygons, no labels.

Olimarao Atoll - Vicinity Map from Yahoo Local Maps - Nothing here.

Olimarao Atoll - Vicinity Map from Bing Maps - And nothing here.

Olimarao Atoll - Vicinity Map from OpenStreetMap - Land polygons and labels.

Google, Yahoo and Bing Maps rely on satellite imagery. The underlying maps of these oceanic island areas are largely neglected in map coverage. Google Maps provides land polygons from a mapping file similar to WVS 1:250,000. OpenStreetMap uses NGA PGS polygons along with NGA Country name files. Clearly the superior map product for oceanic islands is found on OpenStreetMap. But wait! What about a vicinity map using what I call EVS rough precision digitizing. Using Landsat ETM+ imagery, I could quickly digitize island polygons and reefs giving a much clearer map of the island.

Elato, Lomolior and Olimarao Atolls - Landsat N55-05_2000 Coverage

Landsat N55-05_2000 is the imagery I initially tried to work with. As you can see, The vicinity is not covered. It is a blank. So I did what any good mapper would do, improvised. Using Google Earth, I found the blank area and DigitalGlobe had hi-res imagery of the islands located within the blank area.

Elato and Lomolior Atolls - DG Preview Image from GE

Elato and Lomolior Atolls - DG Preview Image from GE Cropped

I decided to use the DG Image Preview from GE. I copied it, cropped it and georectified it. From there, I was able to complete the digitizing within a few minutes. I did this for all islands within the Landsat blank area. Atolls should have reefs digitized as they make up a critically important aspect of this feature. My finished map uses five layers - 1) land polygon 2) reef shallow 3) reef deep 4) ocean and 5) name labels. My island name layer is an extract from NGA's country files.

Olimarao Atoll - Vicinity Map from EVS Rough Precision (1-500,000)

This was all done using Global Mapper. The scale for the above map is 1:500,000. Now that is what I call a real oceanic island vicinity map.

Enjoy!

Thoughts - Continuing Yesterday's "Wow"!

Arutua Atoll - Four EVS Precison Layers Loaded into Google Earth

A reader of EVS Islands suggested that I load my island maps into Google Earth. He had taken the Flickr image of Arutua Atoll and created a Google Earth overlay. He did all of this work by manually matching the EVS image to the GE base image. After viewing his work I had another Wow! moment. It turns out Global Mapper creates KML/KMZ files. I have generated GE KML/KMZ overlays previously, but I thought I would try something different. Using the Arutua Atoll vectors, I created a separate overlay for each vector layer using PNG image format's transparency function. I began with my Reef Shallow and the ocean as my first layer without any color transparency.

Arutua Atoll - Base Layer Reef Shallow with Ocean (1:75,000)

The other three layers would rest atop this base layer. The next three layers were EVS Island Polygons, Vegetation and Inland Water. I made the blue ocean the transparent color for these layers. This resulted in overlays consists of 12 georectified tiles per layer neatly positioning an EVS precision island map into GE.

Arutua Atoll - Four Layers Loaded into Google Earth (1:75,000)

Loading these four layers in proper order (Reef Shallow, EVS Island Polygons, Vegetation and Inland Water) one is able to switch layers on and off to view this atoll from a number of unique perspectives. Pretty cool!

Arutua Atoll - Four Layers in KMZ Files

I have posted the four layers and you are welcome to download them and try them out. They are at the following links: Reef Shallow, EVS Island Polygons, Vegetation and Inland Water. Remember to load Reef Shallow first, EVS Island Polygons second, Vegetation third and Inland Water last. The map is at a scale of 1:75,000. That allows you to view the map at the 4.00 kilometer center read using GE's scale bar. If you take the map below that scale it begins to get ugly fast (blurred lines and colors). Hope you find it interesting. Comments are appreciated, especially KML/KMZ types. I am certain there must be a way to load all layers within one KML/KMZ packet and still be able to retain the ability to pile layers on top of each other and exercise control over whether a layer is on or off. Thanks in advance.

Enjoy

Thoughts - Wow! I Didn't Know Global Mapper Could Do That or Discoveries at 4:00AM

Arutua Atoll FP - EVS Precision Map (1:170,000) - Upper Image

Arutua Atoll FP - EVS Precision map (1:75,000) - Lower Image

At first glance, except for a simple coordinate grid, use of a slightly different map scale and the addition of other necessary cartographic trappings, my original image of Arutua Atoll (upper) looks like the Arutua Atoll (lower). Although the images are both sized at 500 x 347 pixels, to fit into this web page, the two images are quite different. The upper image is JPG, whereas the lower image is PNG. I have been using PNG format images for my last few posts. Supposedly, they give one a better, sharper image at a much smaller size compared to JPG. Frankly, for what I am doing (posting an image of a vector map) the JPG format seemed to work fine. That is until I discovered my Global Mapper "Wow!".

I love my finished maps and enjoy sharing them with readers that appreciate my work. I believe most readers are often content to view an island image, read the brief article, ponder it and then go their merry way. As it should be. However, for the intrepid few that really want to check out the island map, that take the time to select the island image and view the original sized image in Flickr, have I got a treat for you!

If you select the lower Arutua Atoll image and follow it to Flickr, you will be able to view my original sized image of Arutua Atoll at a scale of 1:75,000. Global Mapper, my primary mapping software, allows me to capture a screen's contents to an image.

Global Mapper Image Capture

This is not a new discovery, as I have been using this option for years. But this morning I decided to changed the image size from a default of 1264 x 875 pixels to 2578 x 1750 pixels. This change transformed my 1:150,000 scaled island image into a 1:75,000 scaled island image. My original 1:150,000 scaled image will print on a standard 8.5" x 11" sheet of paper. To print my 1:75,000 scaled image would require a 21" x 14" paper. Within Flickr, the reader can view an image that more nearly displays the island at it's EVS precision viewing limits (between 1:75,000 to 1:50,000). Using Global Mapper to create my images, I am able to generate two additional files that allows one to view the island image with appropriate lat/lons (.pngw and .prj files).

My bottom line discovery - by varying Global Mapper's screen image capture size, I am able to quickly generate EVS precision island maps at meaningful viewing scales. And that's my 4:00 AM "Wow!"

Enjoy!

Por-Bajin - Republic of Tuva's "House of Clay" Island Fortress

Por-Bajin (The square is supposed to be red. Go figure.

Por-Bajin - DigitalGlobe Image from Google Earth (1:2,500)

Por-Bajin - EEVS Map (1-3,500)

A map of an island fortress. Talk about romance, adventure and battles always won!

I read a brief article about Por-Banjin on World Island Info's website. This "House of Clay", the translation of Por-Bajin, is a hot spot for archeological research. Between 2007 to today, researchers and hundreds of students from Russia and a few other countries have made there way to this small island located on Lake Tere-Hole to attempt to understand and reconstruct this mysterious mandala like fortress. Follow this link to Ladybond's blog for an interesting series of photos of this small island.

My map of the island is based on DigitalGlobe imagery taken from Google Earth. I worked at a very large scale to digitize the various layers that make up the map. I show much more vegetation than the photos in Ladybond's blog shows.

This map is a preliminary cartographic sketch of the island, but one that clearly shows the curious Uighur fortress.

Enjoy!

Thoughts - Bennet Island and Mi Vida Loca

Bennet Island - Landsat Image N-54-75_2000 - A Partial View (1:44,260)

Bennet Island - EVS Precision Map - A Partial View (1:44,260)

It has been one very busy school year. As most of your know, I am a middle school teacher. Unless you are a teacher, you probably don't know how wild and crazy that life can be depending on the students, parents and staff. Well, this has been one of those crazy years. Not crazy bad, just crazy busy.

Computers in the Classroom

I am in the process of installing 30 Dell computers in my classroom. The goal is to have a computer with appropriate and consistent software for each student. The software the students will ultimately master consists of Open Office Writer and Impress. They will frequently use MS Paint, ImageForge, Inkscape, Google Earth, Marplot and QGIS or a similar mapping package. Each computer has a high-speed Internet connection, allowing the students opportunities to research projects using on-line resources. Using the suite of software I've installed, the students are able to accomplish almost all classroom tasks, submit completed assignments and receive graded assignments all without resorting to paper copy. My ultimate aim is to ensure each student masters word-processing and presentation software. I want them to prepare high school and college assignments and submit them with confidence derived from extensive experience.

Back to Bennet Island

I like what I've done with this ice covered island so far. At first I traced a shoreline that was an educated guess. The more I've mapped this island, the more I've decided that an ice covered island with rock outcroppings is best mapped as shown above. Map the land that is visible and leave the ice as ice. My busy life, mi vida loca, makes the completion of this map a distant dream. But, finish it I will. Yes, just as soon as I finish teaching my students, installing a room full of computers, cleaning my weed chocked backyard, paying my bills, etcetera, etcetera, etceteera...

Enjoy!

Nisos Aegina GR - An Athen's Island Getaway.

Nisos Aegina - Locator Map

Nisos Aegina - Landsat N-35-34_2000 (1:85,000)

Nisos Aegina - EVS Precision Map (1-85,000)

Nisos Aegina is located only 17.5 kilometers from Athens. The island serves as both a "bedroom" community for Athenians and as a summer getaway for city dwellers. Many of the homes located on this island are second homes of Athenians. Wikipedia has an in-depth article about the island.

Let's talk about the map. I have spent in excess of 6-hours on this map. The challenge was in determining the layers and finding a good color scheme that is pleasant to look at, yet imparts accurate and meaningful information. I used my entire suite of mapping software to complete this project - 1) Global Mapper to create vector layers and identify lat/lon grids. 2) MS Paint to draw the lat/lon grid lines and finally 3) ImageForge to complete the labels and their placement on the map. I realize most decent mapping packages come with these features all included. I am a creature of habit and like my end products. So if it isn't broken, why fix it!

Enjoy!

Thoughts - Bigger is Good, Smaller is Better

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Nisos Aegina - Landsat Island Image Mosaic N-34-35_2000 (1-125,000)

I am currently reworking my map of Nisos Aegina. It is a bedroom island outside of Athens, Greece. A nice little getaway when life becomes too hectic in the big city. But this isn't the reason for this post.

You know that I construct island maps using Landsat ETM+ mosaics as my base imagery. I have a Landsat ETM+ digital library of all of the world's shorelines. I use Global Mapper software to digitize, creating vectors from which i construct my island maps. This software handles the Landsat ETM+ mosaics with ease. I have invested over $500 in Global Mapper and do not regret a cent of it. The software does exactly what I want it to do and Mike, the boss and software guru, keeps making improvements. But this isn't the reason for this post either.

This post poses the age-old question "Is Bigger Better?" as it applies to the world of imagery.

In the world of Landsat derived island specific orthorectified imagery, bigger is not necessarily better. This is the world of imagery anywhere from multi-GB files to a few hundred MB files. These very large image files test the limits of most software packages. Often their formats, (i.e., MrSID) require special handling to open and work with. Since I primarily work with island imagery, I figured that if I were to cut out the ocean and save the island and it's surrounding reefs at a scale allowing me to work at increasing zoom ranges, I could create the same high quality maps from much smaller sized imagery.

First I fashioned a series of Greek island mosaics (see above image). These were followed by a series of Tuamotu Atoll images. I call my creations Landsat Island Image Mosaics (LIIM). Here are a couple of examples showing the zoom capabilities using the Nisos Aegina LIIM as base imagery.

NIsos Aegina - Detail Western Shore LIIM N-34-35_2000 (1-25,000)

Nisos Aegina - Detail Aegina Harbor LIIM N-34-35_2000 (1-12,500)

I typically digitize shorelines and certain land use features at scales between 1:25,000 to 1:12,500. I know that this pushes far beyond the intended limits of Landsat-7, 14.5 meter resolution imagery. I have digitized at these limits for over four years. The resulting maps have a level of quality and precision that exceeds most widely available island mapping. My island maps have been used by a number of universities to further research and as a platform for spatial analysis by insurance companies.

The size advantage with these considerably smaller island images is significant. My LIIMs range in size from 2 MBs up to 45 MBs for very large islands. All of my LIIMs are saved as georectified JPGs. Nisos Aegina LIIM is 3.47 MBs and is a 15.8 MB Tif file. The Landsat image containing this LIIM, on the other hand, is 106 MBs. The image degradation is slight and barely noticeable. So, I will keep using my LIIM of a specific island from which to create my island maps. If you would like to use one of my LIIMs, drop me a line. I'll fix you up.

Enjoy!

Eiao Island FP - Still Revising My Maps

Eiao Island - Google Earth Image (1-60,000) as of March 2007

Eiao Island - Digital Globe Mosaic (1-60,000)

Google Earth and all of us end users have sure benefited from their relationship with DigitalGlobe. From the first blurry image in GE to the exquisite DG mosaic, Eiao Island has never looked better.

Eiao - Map (1:60,000) as of May 2006

Eiao Island - EEVS Precision Map (1-65,000)

My first map of Eiao Island constructed from WVS vector files. In May 2006, I had yet to discover the full extent of resources available to all of us neo-cartographers. I routinely use Global Mapper as my mapping platform. My imagery comes from my Landsat ETM+ library of all the world's shorelines or from DigitalGlobe imagery found in Google Earth. My final island map products are getting better and better. And that's good.

Enjoy!

Bikar Atoll FM - Another Uninhabited Tropical Isle

Bikar Atoll RM (ARB-127)

Bikar Atoll (H.0. 6024) ARB-127

This is the second atoll within the Radak Group that I have mapped in EVS precision. The first atoll was Taongi and now Bikar. Using the maps contained in ARB-127 as inspiration, I have decided to busy myself with maps in this group of atolls. Bikar, like Taongi, is small with only 0.9 sq km of land area. The atoll does contain vegetation, a small forest dominated by pisionia grandis trees. Other than that, the vegetation is scrub size and lower. The atoll is a great nesting place for seabirds.

Bikar Atoll - Landsat Image from N-59-10_2000 (1-75,000)

Bikar Atoll - EVS Precision Map (1-75,000)

The Landsat image used as my base is cloud free and excellent in detail. I did my digitizing at 1:12500 scale, one not practical for viewing, but good for map making. The map took about 2-hours to complete.

Enjoy!

Taongi Atoll - Uninhabited, H-Bombs and My EVS Precision Map

ARB-127 Ornithology of the Marshall and Gilbert Islands

Taongi Atoll (H.O. 6024) ARB-127

Marshall and Gilbert Islands ARB-127

I enjoy reading the Smithsonian Atoll Research Bulletin available at the above link as PDF documents. First encountering them at Scripps Institute of Oceanography's library, I most especially enjoyed the detailed discussion of specific atolls. The articles are scholarly in content, yet accessible to the interested public.

A few years ago I took a class on how to work with enamel. It was instant gratification. Coat the copper plate with different colors of enamel, cook for about 1-minute at 1500°, let cool for 5-minutes and you have your finished work of art. You'll never guess what I made, my very first project was a map of an atoll, Taongi Atoll. I used the ARB-127 map based on chart H.O. 6024. It turned out nice. Why Taongi, why not!

Last week I was browsing my collection of ARB's and was looking at the collection of maps of all of the Marshall and Gilbert Islands which make up a significant portion of ARB-127. I studied the Taongi Atoll map and decided that I would make an EVS precision map of the island. Using Landsat N-59-10_2000 as my base image I constructed my map in about 4-hours. The bulk of the time was spent digitizing the coral heads scattered throughout the lagoon. But more on that later.

Operation Hardtack - Proposal to include Taongi Atoll as H-bomb test site

While researching the atoll, I came across a once classified document proposing that Taongi Atoll be used as a site to explode atomic bombs. This atoll would have been the third atoll besides Bikini and Enewetak, to be catastrophically damaged by slowly desolving nuclear radiation. Cooler heads prevailed and Taongi Atoll was spared. The ordinances intended for Taongi Atoll were exploded at the Nevada test site.

Taongi Atoll - Landsat Image from N-59-10_2000 Standard Landsat ETM+ Colors (1:110,000)

Taongi Atoll - Landsat Image from N-59-10_2000 Modified Colors for Reef Digitizing (1:110,000)

Now for my map. I was convinced I could create a map that would be far superior to the H.O. 6034 version in ARB-127. Looking at the standard Landsat image, I could see that the mapping would be uncomplicated. Curious soul that I am, I decided to play around with colors. After a number of color tweaks, I discovered the puke green image. The shallow reef was a lighter puke green and the deep reef a different shade of green. As a bonus this color tweak turned the island vegetation into a reddish pink. In addition, this color scheme allowed for a greater number of coral head to be digitized.

Taongi Atoll - EVS Precision Map (1:110,000)

And here is my finished map. The scale is 1:110,000 (1 cm = 1.1 km). My finished EVS precision map of Taongi Atoll contain my normal vector layers; island polygon, vegetation, shallow reef and deep reef. I tried something different when labeling. I used a feature in Global Mapper to assign text to a specific point and in this way I assigned lat/lons. The island names and other text were also assigned using Global Mapper. I used MS Draw to construct the lat/lon lines. I think this is a good mapping effort.

Today, the atoll is a nature preserve and remains uninhabited. Thanks to some unknown beaurecrat, the island remains nuclear radiation free!

Enjoy!

Coronado Islands MX - For The Birds and Fishermen

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Coronado Islands - Spot Image from Google Earth (1-35,000)

Coronado Islands - Other Precision Map Using Spot Image From Google Earth (1:35,000)

Located about 25 kilometers south of the entrance to San Diego bay, these Mexican islands are often mistaken as US possessions. Most San Diegans know of these islands and a few of the stories associated with them. For instance, we know that there was a gambling establishment on South Island that was a going concern well into the Depression. We know that the islands were used as a haven for Prohibition smugglers. Today there is a small Mexican military detachment stationed on South Island to keep an eye out for human smugglers and fishing poachers. The islands are visited daily by fishermen, divers and numerous sea birds, especially brown pelicans.

I first saw the islands as a young boy back in 1954. From that perspective they appeared to be two buffaloes. To others they look like coffins. To me they are always a welcome site.

The map was constructed from an image mosaic I created using the Spot image found in Google Earth. From this georeferenced mosaic I was able to work at a scale of 1:5,000. As a result, the shoreline details are excellent. I tried using SRTM 30-meter to generate contours and the results were not satisfactory. I knew of a series of geologic maps of the islands containing 20-meter contours on a San Diego Geology website. I georeferenced the contour containing images and copied the 20-meter contour intervals. When necessary, the contours were adjusted to align with the underlying Spot image.

Because my digitizing work was done at a scale of 1:5,000, the zoom factor for these islands gives one excellent details. I would suggest using Google Earth imagery to take a detailed tour of the islands. To enjoy an excellent map of the islands, this is the place.

Enjoy!

Thoughts - Generating Reliable Contours from SRTM Data

Isla la Plata - Other Precision Map (1-20,000)

Here is a comment and question concerning my use of SRTM data...

I am working on a similar project, in some aspects, about generating contours, and was wondering when the contours do not line up with your coastline (having 25 m intersect the shoreline of your polygon) do you alter the polygon or the raster data before generating the contours? Anyways, I think you work is beautiful, keep it up.

Here is my response...

Thank you for your kind words. I love making maps of islands and to be able to add meaningful contours is a great benefit. However, my experience with the SRTM 30-meter and 90-meter data is as follows. After loading both a georectified image and an SRTM file into Global Mapper, I am able to quickly generate contours at an interval I deem appropriate for the scale I am working with. In nearly every instance the lower level contours do not conform to the actual imaged shorelines. I end up manually realigning the contours to best match the imaged shoreline. As a result my lower level contours are reasonable, but suspect.

When I am dealing with a very large void that cannot be handled by combining SRTM 30-meter with SRTM 90-meter data or be filled with existing void-filling software (I use SRTMFill), I end up guesstimating alignments of contours. Consequently, all of my maps containing contours are as good as the underlying SRTM data - sometimes excellent (upper elevations of Isla la Plata map) and less reliable (10-meter to 30-meter contours and northern contours due to a void).

I am not practiced enough to correct the underlying SRTM ASCII data, so I rely upon working with software (SRTMFill), imagery to contour reconciliation, or when cloud-obscured, an educated guess using secondary imagery.

Hopefully, this answers your questions. Perhaps you have techniques or know of SRTM void-filling software that might correct many of my issues concerning misaligned or voided elevation data. I do believe that SRTM 30-meter and Landsat ETM+ at 14.5-meter resolution can work reasonably well together. However, combining SRTM 30-meter with 1-meter resolution imagery most often creates many slight, but consistent contour misalignments.

SRTM elevation data, as stated above, gives us a reasonable idea of the topography of the underlying land. I would use it to go hiking, but I sure would not bid a construction job based on it.

Enjoy!

Isla la Plata - Ecuador's Bird Island

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Isla la Plata - Landsat Image S-17-00_2000 (1:20,000)

Isla la Plata - DigitalGlobe Island Mosaic from Google Earth (1:20,000)

A group that removes feral animals from islands asked if I could help them with a map of Isla la Plata located off the coast of Ecuador. I said sure and began to search for a map or image of the island. The only map was something that was painted on a sign posted on this island. Not very accurate, but colorful. I tried the Landsat ETM+ image and found it to be obscured by clouds at a number of points on the island. I finally looked into Google Earth and found the DigitalGlobe image that covers the island. Except for clouds over the northern tip of the island, the image is exquisite. To create the above mosaic which is 12.4MBs and 4500 x 4120 lines, I copied 24 images (1280 x 911) and pieced them together. This image was georectified using Global Mapper, Landsat ETM+ and Google Earth coordinates.

Isla la Plata - Other Precision Map (1-20,000)

This is the resulting map. The parties wanting to use the map did not require a vegetation layer so all that I had to map was the island shoreline. That took about 4-hours to map, not just the shoreline, but all of the offshore rocks as well. Finally, using SRTM 90-meter and 30-meter data, I generated 10-meter contour intervals. As so often happens, the 10-meter to 30-meter contours ended up in the ocean. I spent another 4-hours adjusting contours so that they resided on the island and not in the deep blue sea.

This map is done. I hope the party using it will find it helpful. I reminded them that they could not publish this map without permission from DigitalGlobe. It is my experience that DigitalGlobe is very open to allowing maps derived from their data to be used for educational research and perhaps for the removal of feral animals from fragile islands.

Enjoy!