Chociaż co mi szkodzi: Zerknijcie sobie: Odechciewa się pracować…
Hi Ben,
especially Nepal has a new satellite images of good resolution. Especially Digital Globe premium imagery is new and avaiable for all Nepal. In such areas one can recognize singular trees, so I can not agree with the thesis about green pixels.
Having local knowledge one can recognize a lot of information from aerial images and make cathegorization. Even if something get a wrong tag: for instance forest instead of scrub or orchard, this can be modified, when the map is used by local mappers, geographs and/or authorities. We can develop physical boundary map based on existing information. We collect often information without knowing the administrative status, for instance for area=residential.
Having existing GIS system greatly increases the economic development of one country. Or you disagree? Discussion here is superfluous, that´s fact.
I absolutlely agree with steps: first ways, then settlements, buildings, then landuse covering.
Best regards,
Marek
On 2017-06-28 04:07:38 UTC bdiscoe wrote:
please take a look there:
http://www.openstreetmap.org/#map=15/51.1571/18.7358
About 95% of admin_boundary in this district (Wielun) is covered with landuse.
Yes, this is possible in some places (like most of Europe) because of a highly developed set of property markers, physical survey, geodetic control, DEM resolution sufficient for tight rectification, laws which enforce boundaries and landuse, and many other factors.
NONE of those exist in Nepal. It is physically and practically impossible to do anything similar in places like Nepal by simply tracing imagery.
It is foolish and misleading to draw a polygon and tag it “landuse=forest” just because it happened to have some density of green pixels at the time a satellite passed overhead sometime up to 10 years ago.
What we CAN do, is trace roads and buildings, and (for a very loose approximation) some rough woods extent, which is highly approximate. If you place landuse nodes closer than 3m, you are just adding noise to the OSM database. There is not 3m certainly on what is, or is not, being used for forestry, or any other landuse.
I have been working on Nepal (and Lesotho, and Somaliland, etc. etc.) for many years, and will continue to do so. If we could get to a complete roadmap for Nepal, even 2-10 years out of date as most of the imagery is, that would be a HUGE accomplishment.
Best wishes,
Ben