A Map Series
This is a technical article that shows you step by step how to create a raster dataset in SDE from multiple georeferenced image files. Todd Zagurski from Regional Planning and Mark Greninger from the CIO’s office created this document.
Problem: You have a map series that has been scanned and georeferenced, but exists as many individual images which makes access cumbersome.
Solution: Use these instructions to create a single seamless raster dataset.
Additional Benefit: By creating a single seamless image, you will able to see any errors in your referencing at a glance – holes show up extremely quickly.
LA County’s Regional Planning Department had scanned 3 historic map series (House Numbering Maps, Index Maps, and Township, Range Section Maps). Each series of maps included between 50 and 100 maps that were part of a map grid (see an example snapshot to the right).
The goal was to create a single, seamless raster dataset in our Enterprise GIS database that would enable Regional Planning to view the entire series as a single image. There were a number of issues, including the fact that each scanned image had a slightly different pixel size (meaning the sderaster mosaic command wouldn’t work). As well, most of the images were single-band (gray scale), but a couple were color, causing issues too.
A fair amount of effort was expended getting the data right, but now it’s a single seamless raster dataset available through a single dataset.
The documents below include detailed instructions on how to flatten your data, create a raster dataset, and load the data into your database using the Workspace to Raster Dataset command.
WS 2 Raster
Raster Dataset (seamed)
The GNIS viewer
No – not literally (although an earthquake could make that happen). What is happening is that someone has made a suggestion to extend the definition of the San Gabriel Mountains further to the northwest than they currently are. This happens in LA County once in a while, so I thought I’d pass things along as a little instruction on how things get named the way they are. It turns out there’s a process for that, and after a while these things come to me.
“The U. S. Board on Geographic Names (GNIS) is responsible by law for adjudicating decisions regarding geographic names for use by the departments and agencies of the Federal government. The Board has received a proposal to change the extend the application of the name San Gabriel Mountains to encompass a larger area extending to the northwest to include Liebre Mountain, Sierra Pelona and Sawmill Mountain. Because local opinion is very important to the Board, we would like the County’s opinion concerning the proposed application change.”
Continue reading San Gabriel Mountains may be growing in size
Open Data License
This has been in the back of my mind for a while, so I thought I’d get opinions on what we should do with the GIS data that we create and share. What I am trying to avoid is a reseller packaging and re-selling our GIS data without:
- Adding value, and
- Giving credit back (attribution).
At the recent Geocoding conference, I had a discussion with an expert, who pointed me to the Open Data Commons licenses.
I just took a look, and they have three flavors:
So – we’ll get there soon enough, but if you have an opinion as to how we should license our data, let me know!
I was looking at Google Maps this morning and noticed something odd – a street one block from my office was renamed! Now the way the City of LA works, I figured there would have been a big hullabaloo about this, but I hadn’t seen anything.
Well, it’s probably just an error – so I checked a couple of sources (Bing, Yahoo Maps, Open Street Map, Esri)…you know, the usual suspects. They all have it as N Hill St – so I’m pretty sure I’m right. But Google has it as ‘W 1st St Road’. So there are about seven (7) blocks mislabeled (from 1st Street in the Civic Center to Ord St. in Chinatown). Doing an address search in that range just kicks you back to S Hill St., but that’s not right either.
So I fired up Google Map Maker, so I could let them know. I made the proposed change relatively smoothly, so we’ll see. Now the last time I did an edit using Google Map Maker I was basically fighting with the Google Team about a label that was off about a half a mile. They fixed it eventually – but every e-mail kept saying they denied my update.
So keep your fingers crossed that this gets updated before someone makes a wrong turn somewhere!
by jh, December 20th, 2011
From their website, the “OSGeo was created to support the collaborative development of open source geospatial software, and promote its widespread use.” A presentation at slideshare.net offers a useful summary.
OSGEO also sponsors the annual FOSS4G (Free Open Source Software for Geospatial) conferences, with FOSS4G 2012 being held in Beijing, China next September. No plans to go to China? No Worries! There is plenty of talk on open source GIS software at CalGIS 2012 in Sacramento in April.
Sorry for the late notice, but I look forward to seeing everyone tomorrow (Tuesday the 20th of December) at our normally scheduled eGIS Committee Meeting.
Here is the agenda: December 2011 – eGIS meeting notice and Agenda (pdf file)
We’ll recap and go over GIS Day, which was (once again) a great success! I have copies of the “GIS Day Proclamation” scrolls for GIS Day committee members – here’s a link to the image, and I have also have signed copies of the pictures from the group that received them!
We’ll also give an update on the Thomas to TIGER conversion project, and I’ll focus a bit of time on the Location Management System, since that is becoming more and more used.
See you there!
A Google Maps mashup shows up to date road closures in LA County. You can also view a list of closures.
I was the keynote for the 2nd day of the recent 1st International Geocoding Conference which was a great conference hosted by USC and ESRI this week. I thought I would pass along the discussion about our address program as well as a method to find false matches in geocoding:
Using GIS to improve Addressing – Geospatial Address Summit 2011_12 (.pdf)
Bill A’Hearn from Glendale passed this along – now advertisements will be embedded in the physical world? Don’t know what a QR code is? You will recognize it immediately!
My question after reading the article is: how will this company guarantee that the code will be loaded into Google or Bing or Yahoo maps? What is the accuracy of the imagery that they will be taking – it would be pretty bad if the new image was shifted over by 10 feet, causing some serious confusion. And what about consistency – we could have little images all over the place that don’t have the same date as the imagery next to them …
Passing this along:
Dear Maps API Premier customers,
Do not use a Google Maps API V2 key when loading the Maps API V3
key parameter, no action is required.
key parameter to provide their API key (e.g.
key=ABQI...) in the requests to the API, whereas Maps API Premier applications need to use the
client parameter to provide a Maps API Premier Client Id, e.g.
client=gme-yourclientid in the requests. If you migrated your application over from the the v2 JS API to the v3 JS API, it’s possible you also migrated over your v2 style key to your v3 JS API application
We have notified those Maps API Premier customers that are sending a Client Id either in the key parameter (e.g.
key=gme-yourclientid) or in conjunction with the key parameter(e.g.
client=gme-yourclientid&key=ABQI... in V3 JS API requests. Sites that continue to send such requests will be rejected in the near future and will not receive the benefits entitled by their Maps API Premier license.
If you continue using applications using the
key in the request for the Maps API, please change this into
client=gme-yourclientid and make sure to remove the
Please see details about how to provide your Client Id to the API services in our Premier documentation:
Google Maps API Premier Developer’s Guide