Comments for Gothos

Comment on Transform Projections with GDAL / OGR by Frank

Frank — Fri, 26 Jun 2009 21:31:53 +0000

Hello jagdishb – if you have a file that is undefined, but you know that its projection or coordinate system is part of the EPSG library (based on metadata for your file), you can go to spatial reference to look up the EPSG code and then reference that code in the ogr command: ogr2ogr -a_srs EPSG:code output.shp input.shp. The input file is your undefined file, and the output is your new file with the definition.

In the examples I used, I didn’t create the wkt from an esri shape file – I generated it from the spatial reference site. You can use it to look up EPSG codes (first example) or to create WKT for projections or coordinate systems that aren’t in the EPSG library (subsequent example) that ogr can reference (either as a text file that I downloaded, or as hobu pointed out a url).

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Comment on Transform Projections with GDAL / OGR by jagdishb

jagdishb — Fri, 19 Jun 2009 07:36:56 +0000

Thank you Frank for valuable blog. In this you have explained about reprojecting a dataset to an epsg undefined CRS by creating a wkt.txt file from the esri shape file. But I need a solution just opposite this..i.e. I have data in epsg undefined projection , and want to convert to epsg defined CRS. Thanks

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Comment on Image Formats for Exporting Maps by lucideer

lucideer — Sun, 07 Jun 2009 09:52:56 +0000

Hey Frank, I came to your site from a google search about svg in web development (an interest of mine) and happily found an entire site on cartography (another interest – though something I admittedly know considerable less about).

Anyway, though this article is now almost a year old, and I’m not usually one to be overly pedantic, I thought I may as well comment. Where you say “you can embed them into html using an object or embed tag (can’t use the standard img tag)” – this is not entirely accurate. I see you’re a Firefox user (from your handy little icon on the right) which is probably the source of the misconception. It’s a popular browser, so many people believe “if Firefox can’t do it it can’t be done”. However relatively speaking Firefox’s support of web standards is quite poor, it’s support of SVG in particular, and all good browsers will support the standard img tag. This Firefox bug is due to be fixed soon too apparently.

As for using Wikipedia’s rsvg solution server-side for IE, that is only used in Wikipedia as it is a large site with millions of users uploading millions of SVGs, so the operation must be done “on-the-fly”. If you’re handling all the SVGs yourself personally, you can rasterise them manually on your computer at home before sending it up to the server. No need for complicated server-side nonsense.

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Comment on Transform Projections with GDAL / OGR by leegee

leegee — Mon, 04 May 2009 11:25:15 +0000

Thank you very much for this invaluable information, my first steps in this field — explained all I needed to know to get going.
Cheers
Lee

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Comment on Transform Projections with GDAL / OGR by Frank

Frank — Sat, 25 Apr 2009 15:52:46 +0000

That’s great! Many thanks for pointing that out.

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Comment on Transform Projections with GDAL / OGR by hobu

hobu — Wed, 15 Apr 2009 17:06:57 +0000

For the sr.org URLs, you can use them directly with ogr2ogr instead of manually downloading them if your OGR has cUrl support (needed for WMS and a number of other drivers).

ogr2ogr -a_srs http://spatialreference.org/ref/esri/54030 states_nad83.shp states_unknown.shp

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Comment on Comments Disabled by Frank

Frank — Sat, 07 Mar 2009 17:00:04 +0000

As of March 7, 2009 comments are now enabled for registered users. I’ve got the email situation sorted out. If you’ve registered and never received a reply, try registering again and you should receive an automated response

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Comment on Adding Long / Lat XY Data to ArcMap by Frank

Frank — Sat, 07 Mar 2009 16:41:45 +0000

Unfortunately, as of 3/7/2009, it looks like the SAHIMS page where I downloaded the boundary file for Botswana is kaput – there’s a generic place-holding page in its place that says that the domain has expired. You can find comparable shapefiles for countries from many sources – gData at Berkeley is a good example.

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Comment on GIS Data for Africa by Frank

Frank — Sat, 07 Mar 2009 16:36:37 +0000

Unfortunately, as of 3/7/2009, it looks like the SAHIMS site is kaput. You get a generic place-holding page that says that the domain has expired.

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Comment on Adding Long / Lat XY Data to ArcMap by Bookmarks about Longitude

Bookmarks about Longitude — Sat, 03 Jan 2009 14:00:15 +0000

[...] http://www.lpod.org/ots/?p=2508 – bookmarked by 5 members originally found by aii on 2008-12-24 Adding Long / Lat XY Data to ArcMap http://gothos.info/2008/07/07/adding-long-lat-xy-data-to-arcmap/ – bookmarked by 3 members [...]

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