Thoughts - What If EVS Precision Maps Were Included in OpenStreetMap?

OpenStreetMap - Arutua Atoll - NGA PGS Shoreline Map

I've been making EVS Precision island maps for well over three years. Using Landsat ETM+ imagery as my base image from which I have created most of my 10,000 plus island polygons. All of my island maps currently reside on my E-Drive and on my I-Drive. Lots of islands doing few people any good. About three weeks ago a person from Google contacted me and wanted to discuss EVS Islands. I continue to hold out hope that my EVS Precision island maps will be licensed by one of the big three map folks. So far, I still have the 10,000 islands on my computer.

A number of readers have suggested I upload my island map files into OpenStreetMap. I have resisted the suggestion. I keep thinking that someone will want to pay me a fee to use my island maps.

The question I pose to my knowledgeable readers, "Who owns my map files if they are posted to OpenStreetMap? Do I continue to own them? Could I sell them to another user, yet still keep them on OpenStreetMap?

OpenStreetMap - Arutua Atoll - EVS Precision Map

If EVS Precision island maps were posted to OpenStreetMap this is what the user could view. That is if all four to five layers of information were included. I would suggest an ocean color change. My ocean blue looks a lot better than OSM's puke green color.

Depending on the answers to my previously posed questions will help me to determine whether I should post my EVS Precision island maps. Any answers?

Enjoy!

How To Digitize EPIP's Four Atoll Layers

What is EPIP?

Enhanced Vector Precision Island Polygons - Using Landsat ETM+ ortorectified image mosaics as my base images, I digitize various layers of information, most typically from islands. I use Landsat ETM+ because: 1) It is free. 2) It is typically cloud-free. 3) It is consistent in quality. 4) It covers the earth. 5) It is virtually copyright free. This is the degree of precision over 8,000 South Pacific island polygons have been digitized to. This level of digitizing precision over such a broad expanse (South Pacific) is quite an accomplishment. What does this level of digitizing precision entail? What are the layers of information being captured?

Atoll Digitizing - First Layer Vegetation (Hi-Lo)

The first layer I digitize is vegetation. Working at a scale of between 1:25,000 to 1:15,000, I carefully digitize layer outlines. Working with the vegetation layer, I have been known to make a number of vegetation classifications. For the purposes of EPIP, I make one classification - Vegetation (Hi-Lo). This broad classification focuses primarily on land vegetation. I am reasonably certain I digitize some patches of reef vegetation as well.

Atoll Digitizing - Second Layer Island Polygon

My second layer of information is the island polygon. As the name implies, this should be any above-water land feature. When digitizing an atoll made up of many small motus located on a complex reef that is often awash the difference between above-water, reef awash and below-water can get fuzzy. It is within this layer that I am certain I include reef features that are either awash or just below water. In this layer, I prefer to digitize too much as opposed to too little. Perhaps the next generation of Landsat imagery will allow for a clearer land vs reef determination. Until then, I'll digitize in as consistent a manner as possible.

Atoll Digitizing - Third Layer Reef Shallow

This is another layer that I have used a number of classification. For the purposes of EPIP, whatever is visible (shade of blue) that I have not classified as a island polygon, makes up my Reef Shallow layer. This layer on the outer reef edge is typically defined by waves and/or a faint blue area along the shore. The inner reef shore also contains this blue area in varying shades and thicknesses. All of these blue areas are classified as Reef Shallow for the puposes of EPIP.

Atoll Digitizing - Fourth Layer Reef Deep

The final layer is Reef Deep or the central lagoon. It is basically everything within the atoll that isn't an island polygon or reef shallow. A crude classification, but it works well for EPIP.

I do all of my digitizing using Global Mapper. It is: 1) dependable 2) fairly inexpensive 3) simple to use 4) produces consistent product and 5) is serviced by Mike, absolutely the best customer service/owner of a product.

Atoll Digitizing - EPIP's Four Atoll Layers

And there you have it, EPIP's four atoll layers in all their glory. I'll share a few of my recently completed atolls with you. North is up and I realize they are unfinished maps without lat/lon, titles, north arrow and such, but they make the point, EPIP is a quality product.

Tahanea Atoll - EPIP (1:200,000)

Motutunga Atoll - EPIP (1:100,000)

Tunake Atoll - EPIP (1:50,000)

Tepoto Atoll - EPIP (1:25,000)

Enjoy!

Arutua Atoll FP - Beautiful Atoll and Long Mapping Hours

Arutua Atoll FP - Base Image From Landsat S-06-15_2000 (1:170,000)

Arutua Atoll FP - EVS Precision Map From Landsat S-06-15_2000 (1:170,000)

According to a Wikipedia entry, Arutua Atoll has a population of 500 with the majority living in Rautini Village. These hearty souls earn their living off of copra, fishing and pearling.They do have a small airfield located on their island.

Let's talk about what went into the construction of this map. I worked in excess of 12-hours on this map over a period of 4-days. The excessive amount of time devoted to this project had to do with the size of the atoll (31-km by 24-km). This map consists of 812 unique features. The majority of these unique features are motus (small island polygons) and coral heads within the lagoon. The trick to digitizing this atoll is determination, patience and cloud-free imagery. I initially worked off of the Landsat ETM+ mosaic, digitizing at scales between 1:25,000 to 1:12,5000. The digitizing process was tedious and tiring, but the final map looks great.

Arutua Atoll FP - Rautini Village From DigitalGlobe Image (1:6,800)

Arutua Atoll FP - Rautini Village in Other Precision Map From DigitalGlobe Image (1:6800)

Just for the fun of it, I digitized Rautini village using a DigitalGlobe image from Google Earth as my base image. The village took about 2-hours to complete. I added the road layer as a bonus feature.

All in all, I am pleased with this series of maps and I hope you find them interesting.

Enjoy!

Spinalonga Island Crete - Site of One of Europe's Last Leper Colonies

Spinalonga Island - Locator Map

Spinalonga Island Crete - DigitalGlobe Image from Google Earth (1:3,500)

Spinalonga Island Crete - Other Precision Map - DigitalGlobe Image from Google Earth (1:3,500)

Once the site of a Venetian fortress built to protect the harbor to the southwest. For decades this fortress turned away invading forces, pirates and unwelcomed visitors. As happens to all fortresses, this one was ultimately overrun and then abandoned. For years this small island was home to no one. At the turn of the last century the island was reinhabited. From 1903 to 1957 the island's guests were lepers. Where other inhabitants had abandoned Spinalonga for new homes, these poor souls were abandoned to the island, outcasts from society. Those of you interested can find an article about Spinalonga Island on Wikipedia. Now days the island is a popular tourist destination. I'm not sure it would be high up on my list of "sites to see" as I travel about the Greek islands. But, everyone to their own desires.

Spinalonga Island - Looking at it from west to east.

I worked off of the DigitalGlobe image taken from Google Earth to create my Other Precision map of Sinalonga Island. As the island is quite small, the 1-meter resolution imagery allowed for a detailed study of the island to include remains of the fortress and the leper colony. The mapping took about 3-hours from start to finish.

Enjoy!

Comparison - 14.5-meter vs 1-meter and Monoplotted Shorelines

Landsat ETM+ and DigitalGlobe from Google Earth (1:18,000)

I have heard from many readers that maps derived from 14.5-meter resolution are useable between 1:125,000 to 1:62,500. To push them down to scales below 1:62,500 would render the map virtually useless.

Palmerston Atoll - Bird Islands (1:15,000)

That was before I discovered a LINZ produced map of Palmerston Atoll at a scale of 1:25,000. My EVS precision shoreline was a very close approximation of the LINZ product. It was so similar that it was as if LINZ might have used the 14.5-meter resolution imagery to produce their island map. I asked them and never got a satisfactory answer. My guess is that they did make use of the 14.5-meter imagery to produce their 1:25,000 scale map. Just a guess, but a good one.

EVS Precision and EEVS Precision Shorelines with Reefs (1:18,000)

Using the first image in Global Mapper, I digitized both shorelines at 14.5-meter resolution and 1-meter resolution. The left map (less vegetation layers) was created from 14.5-meter imagery. The map on the right was created from 1-meter imagery. I am certain DigitalGlobe's 1-meter imagery is the best hi-res imagery currently available, thanks to Google Earth. I confidently acknowledge that shorelines, reefs, vegetations layers and other layers of information derived from 14.5-meter resolution imagery is good mapping information. As with any imagery, one needs to make mapping compromises. Perfection at tracing a dynamically shifting shoreline is impossible. Tha shoreline's ultimate delineation can be approximated, at best. My EVS precision work allows me to create and use mapping products at scales far below 1:62,500 - like 1:25,000.

Enjoy!

Comparison - LINZ 1:25,000 Map to EVS Map

I have been told by more photogrammetrist and cartographic professionals that Landsat ETM+ imagery is only reliable, for map production, between 1:125,000 and 1:62,500. Anything larger would not be cartographically sound. Good soul that I am, I believe them.

I understand that this imagery has pixel resolution reputed to be 14.5-meters at best. The way it has been explained is that each pixel resolves 14.5-meters of the earth, rendering Landsat ETM+ imagery as a satisfactory base from which to create maps at scales between 1:125,000 to 1:62,500.

It seems that Land Information New Zealand (LINZ) did not get the memo. Their Palmerston Atoll map, which I use throuhout this comparson, shows the same shoreline twists and turns my EVS Landsat ETM+ derived map does. They claim their map scale is 1:25,000 and without hesitation offer it to the world.

Close comparison of my EVS precision map and the LINZ Palmerston Atoll map are strikingly similar. Our shorelines are nearly identical. Our depiction of vegetation and reef layers are near mirror images.

I asked a representative of the LINZ cartographic group if Landsat ETM+ imagery was used in the production of their Palmerston Atoll map. He promised to get back to me with an answer. He never did. I suspect that LINZ cartographers used Landsat ETM+ imagery as an important foundational layer in the production of their Palmerston Atoll map. I, on the other hand, used Landsat ETM+ as my ONLY foundational layer.

So, all of you photogrammetrist and cartographers that are convinced Landsat ETM+ should only be used to produce maps at scales of 1:62,500 and smaller should explain to the LINZ cartographers that their 1:25,000 scale maps are not sound or, perhaps, give more credibility to Landsat ETM+ imagery. It seems that Landsat ETM+ base imagery can be made to work at 1:25,000 and EVS precison mapped shorelines are damn good!

Enjoy!

Pulau Sematan ID - Kidney Bean Shaped Island

Pulau Sematan ID - Offshore Island Near Pulau Sulawesi

Pulau Sematan ID - Image From Landsat ETM+ N-50-00_2000 (1:62,380)

Located off of the northern coast of Pulau Sulawesi, is Pulau Sematan. After much research I have learned it is a dive destination and home to a few hardy fishermen. It is covered with lush vegetation and based on it's proximity along the equator, it is most likely, hot, humid and wet.

Pulau Sematan ID - EVS Precision Map With 50-Meter Contour Intervals (1:62,380)

The map itself was fast to do. From start to finish it took about 3-hours. Nothing particularly challenging, just a nice EVS precision map of a small island.

Enjoy!

Dao Bach Long Vi VN - Another Look at a Past Project

Dao Bach Long Vi - Landsat Image N-48-20_2000 (1-17,500)

Dao Bach Long Vi - Marplot Map (1-17,500)

I haven't posted one of these in a long time. It is an Enhanced Vector Shoreline of a Vietnamese island. It seems that I posted this before, but I'll be darned if I can find it on my site. Oh, well.

Dao Bach Long Vi is a potential Marine Protected Area. For now, it is home to a lighthouse and a small population of fishermen. There are a series of photos posted in Google Earth that show interesting views of places about this island. It is home to military, fishermen and an occasional tourist.

Dao Bach Long Vi - Marplot Map (1:17,500) - A Fancy Map

Yes siree, this is a fancy map. I took my original map, less lat/lon and scale box, and worked it over in my free paint program, ImageForge. I am still experimenting with fonts and text (credits and such), but the overall composition looks good. It took an extra two-hours to complete this project, but it is well worth it.

View Dao Bach Long Vi on Google Maps

Enjoy!

Thoughts - 125,000 Named Islands

125,000 Named Islands

Prior to beginning my island mapping blog, I downloaded country name files and extracted all names that applied to an island. I ended up with 125,000 island names.

I have mapped 10,000 plus or minus at EVS precision over the last 5-years. I only have another 115,000 named islands left to map. I should finish in about 60 years at my current rate. I think I might need some help. Any takers?

Enjoy!

Musandam Peninsula OM - 50-Meters Contours Using Plans One Through Four

Musandam Peninsula - EVS Precision Map (1-175,000)

I posted the above map of the Musandam Peninsula a few weeks ago. The geography is fascinating. However, I knew more work had to be done to complete my map. Specifically, I wanted to create contours to overlay onto the area.

My first attempt, Plan One, was straightforward - download the SRTM HGT file, load it into Global Mapper, generate contours and I would be finished . . . Whoops! Not so. It turns out that the SRTM HGT file for this area is full of voids, those nasty little holes of nothing. With voids my generated contours were grossly inaccurate.

I've been at this mapping business long enough to know that if one source doesn't work, there is most probably another, like Plan Two - the CGIAR-CSI SRTMs. These are void filled versions of the HGTs. I downloaded the appropriate SRTM tile, loaded it, generated contours and . . . Whoops! Not quite right.

Still not to be deterred, I went to Plan Three - using a void-filling piece of software called Void Killer 2 I tacked the contour generating problem once more. I am aware of a number of freeware SRTM void fillers, but I wanted to try the trial version of VK. I downloaded the trial copy, unzipped it and loaded the requisite SRTMs . . . Whoops! Won't let me make a copy and I didn't want to spend $43 to test it's claim as the best void filling software.

Musandam Peninsula - EVS Precision Map with 50-Meter Contour Intervals (1-175,000)

Plan Four to the rescue. In order to use Void Killer 2, it was necessary to convert the CGIAR-CIS SRTM tile from TIFF into DEM format. I loaded this DEM tile on top of the void peppered HGT file and generated contours . . . voila! It worked. Somehow the combination of the two sandwiched together allowed GM to generate contours without voids. Some of the 50-meter contours spill across water versus land, but that can be cleaned up. The HGT voids were filled with reasonable contours. The combination of SRTM HGT and SRTM DEM did the trick.

I would caution the state of Oman - Gentlemen, don't embark upon a multi-million petro-dollar project based upon these contours. However, I am confident that GM's contour generating algorithm is sound for the intrepid Omani backpacker, who could rely on these contours with a fair level of confidence.

Enjoy!